HomeMy WebLinkAboutGalveston County HMP_Volume 1_APA2022 Multi-Jurisdictional2022 Multi-Jurisdictional
Hazard Mitigation PlanHazard Mitigation Plan
Galveston County
Volume I
May 2022
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Galveston County, TX | Hazard Mitigation Plan i
2022 Update
Table of Contents
Table of Contents ................................................................................................................................................... i
SECTION 1. INTRODUCTION ...................................................................................................................... iv
1.1 Purpose ................................................................................................................................................. 1-1
1.2 Background .......................................................................................................................................... 1-1
1.3 Plan Organization ................................................................................................................................. 1-1
1.4 The Updated Plan – What is Different? ............................................................................................... 1-4
SECTION 2. PLANNING PROCESS ............................................................................................................ 2-1
2.1 Introduction .......................................................................................................................................... 2-1
2.2 Organization of the Planning Process .................................................................................................. 2-2
2.2.1 Organization of Planning Partnership ........................................................................................... 2-2
2.2.2 Planning Activities ........................................................................................................................ 2-5
2.3 Stakeholder Outreach and Involvement ............................................................................................... 2-7
2.3.1 Federal, State, and County Agencies ............................................................................................ 2-7
2.3.2 Regional and Local Stakeholders .................................................................................................. 2-8
2.3.3 Stakeholder Survey Summary ..................................................................................................... 2-10
2.4 Public Participation – Resident Involvement ..................................................................................... 2-12
2.5 Incorporation of Existing Plans, Studies, Reports, and Technical Information ................................. 2-13
2.6 Integration with Existing Planning Mechanisms and Programs ......................................................... 2-14
2.7 Continued Public Involvement ........................................................................................................... 2-14
SECTION 3. GALVESTON COUNTY PROFILE ........................................................................................ 3-1
3.1 General Information ............................................................................................................................. 3-1
3.2 Major Past Hazard Events .................................................................................................................... 3-1
3.3 Physical Setting .................................................................................................................................... 3-2
3.3.1 Location ........................................................................................................................................ 3-2
3.3.2 Topography and Geology .............................................................................................................. 3-2
3.3.3 Hydrography and Hydrology ........................................................................................................ 3-3
3.3.4 Climate .......................................................................................................................................... 3-3
3.3.5 Land Use and Land Cover ............................................................................................................ 3-3
3.4 Population And Demographics ............................................................................................................ 3-5
3.4.1 Vulnerable Populations ................................................................................................................. 3-6
3.4.2 General Building Stock ................................................................................................................. 3-7
3.4.3 Land Use Trends ........................................................................................................................... 3-8
3.4.4 Population Trends ....................................................................................................................... 3-10
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3.4.5 Future Growth and Development ................................................................................................ 3-10
3.5 Lifelines and Critical Facilities .......................................................................................................... 3-10
3.5.1 Safety and Security ..................................................................................................................... 3-11
3.5.2 Food, Water, and Shelter Lifelines ............................................................................................. 3-13
3.5.3 Health and Medical Lifelines ...................................................................................................... 3-13
3.5.4 Energy (Power and Fuel) Lifelines ............................................................................................. 3-16
3.5.5 Communication Lifelines ............................................................................................................ 3-16
3.5.6 Transportation Lifelines .............................................................................................................. 3-16
3.5.7 Hazardous Materials Lifelines .................................................................................................... 3-20
SECTION 4. RISK ASSESSMENT ............................................................................................................... 4-1
4.1 METHODOLOGY AND TOOLS ....................................................................................................... 4-1
4.1.1 Risk Assessment Tools ................................................................................................................. 4-1
4.1.2 Risk Assessment Approach ........................................................................................................... 4-2
4.1.3 Sources of Data Used in Hazus Modeling and Exposure Analyses .............................................. 4-5
4.1.4 Limitations .................................................................................................................................... 4-7
4.2 IDENTIFICATION OF HAZARDS OF CONCERN .......................................................................... 4-8
4.2.1 Changes from the 2017 Hazard Mitigation Plan ........................................................................... 4-8
4.2.2 Hazard Groupings ......................................................................................................................... 4-8
4.3 Hazard Profiles ................................................................................................................................... 4-12
4.3.1 Erosion ........................................................................................................................................ 4-12
4.3.2 Dam and Levee Failure ............................................................................................................... 4-25
4.3.3 Drought ....................................................................................................................................... 4-37
4.3.4 Expansive Soils ........................................................................................................................... 4-45
4.3.5 Extreme Temperature .................................................................................................................. 4-52
4.3.6 Flood ........................................................................................................................................... 4-60
4.3.7 Hail .............................................................................................................................................. 4-81
4.3.8 Hurricane and Tropical Storm ..................................................................................................... 4-87
4.3.9 Land Subsidence ....................................................................................................................... 4-103
4.3.10 Lightning ............................................................................................................................... 4-107
4.3.11 Pandemic ............................................................................................................................... 4-114
4.3.12 Severe Winter Storm ............................................................................................................. 4-121
4.3.13 Thunderstorm Wind .............................................................................................................. 4-129
4.3.14 Tornadoes ............................................................................................................................. 4-142
4.3.15 Tsunami ................................................................................................................................ 4-151
4.3.16 Utility Failure ........................................................................................................................ 4-157
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4.3.17 Wildfire ................................................................................................................................. 4-163
4.4 Risk Ranking .................................................................................................................................... 4-173
4.4.1 Hazard Ranking Methodology .................................................................................................. 4-173
4.4.2 Hazard Ranking Results ............................................................................................................ 4-179
SECTION 5. CAPABILITY ASSESSMENT ................................................................................................ 5-1
5.1 Update Process Summary..................................................................................................................... 5-1
5.2 Planning and Regulatory Capability .................................................................................................... 5-2
5.2.1 Planning and Regulatory Capabilities – County and Local .......................................................... 5-2
5.2.2 Planning and Regulatory Capabilities – Federal and State ........................................................... 5-4
5.3 Administrative and Technical Capabilities ........................................................................................ 5-11
5.4 Fiscal Capabilities .............................................................................................................................. 5-12
5.5 Plan Integration .................................................................................................................................. 5-21
5.5.1 Integration Process ...................................................................................................................... 5-21
SECTION 6. MITIGATION STRATEGY ..................................................................................................... 6-1
6.1 Introduction .......................................................................................................................................... 6-1
6.2 Background and Past Mitigation Accomplishments ............................................................................ 6-1
6.3 General Mitigation Planning Approach ............................................................................................... 6-2
6.4 Strengths, Weaknesses, Obstacles, and Opportunities Exercise .......................................................... 6-3
6.5 Review and Update of Mitigation Goals and Objectives ..................................................................... 6-3
6.5.1 Goals and Objectives .................................................................................................................... 6-3
6.6 Mitigation Strategy Development and Update ..................................................................................... 6-4
6.6.1 Review of the 2017 HMP Mitigation Action Plan ........................................................................ 6-4
6.6.2 Identification and Analysis of Mitigation Techniques .................................................................. 6-5
6.6.3 2022 HMP Mitigation Action Plan ............................................................................................... 6-5
6.6.4 Mitigation Best Practices .............................................................................................................. 6-6
6.6.5 Mitigation Strategy Evaluation and Prioritization ........................................................................ 6-7
6.6.6 Benefit/Cost Review ..................................................................................................................... 6-8
SECTION 7. PLAN MAINTENANCE ........................................................................................................ 7-10
7.1 Monitoring, Evaluating and Updating the Plan .................................................................................. 7-10
7.1.1 Monitoring .................................................................................................................................. 7-11
7.1.2 Integration Process of the HMP into Municipal Planning Mechanisms ..................................... 7-12
7.1.3 Evaluating ................................................................................................................................... 7-14
7.1.4 Updating ...................................................................................................................................... 7-16
7.1.5 Grant Monitoring and Coordination............................................................................................ 7-16
7.2 Implementation of Mitigation Plan Through Existing Programs ....................................................... 7-17
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7.3 Continued Public Involvement ........................................................................................................... 7-22
SECTION 8. PLANNING PARTNERSHIP ................................................................................................ 8-24
8.1 Plan Maintenance Procedures ............................................................................................................ 8-24
8.2 Initial Solicitation and Letters of intent .............................................................................................. 8-24
8.3 Planning Partner Expectations ........................................................................................................... 8-24
8.4 Jurisdictional Annex Preparation Process .......................................................................................... 8-25
8.4.1 Data Collection ........................................................................................................................... 8-25
8.4.2 Hazard Ranking Exercise ............................................................................................................ 8-25
8.4.3 Strengths Weaknesses Obstacles and Opportunities (SWOO) Exercise ..................................... 8-26
8.4.4 Mitigation Strategy Workshop .................................................................................................... 8-26
8.4.5 Municipal Support Conference Calls .......................................................................................... 8-26
8.4.6 Jurisdictional Annexes ................................................................................................................ 8-26
8.4.7 Annex Review ............................................................................................................................. 8-28
8.5 Coverage Under the Plan.................................................................................................................... 8-28
References ............................................................................................................................................................. 1
SECTION 1: INTRODUCTION
Galveston County, TX | Hazard Mitigation Plan 1-1
2022 Update
SECTION 1. INTRODUCTION
1.1 PURPOSE
Galveston County and 11 of its jurisdictions have prepared this hazard mitigation action plan update to better
protect the residents and property throughout the County from the effects of hazard events. This plan
demonstrates the County’s and each jurisdiction’s commitment to reducing risk from hazards, increasing
resilience overall, and provide a tool to help decision makers integrate mitigation in their day -to-day processes.
This plan was also developed to position Galveston County and its participating jurisdictions for eligibility of
pre- and post-disaster Federal Emergency Management Agency (FEMA) grants, including Hazard Mitigation
Assistance grant programs (HMA), which include Hazard Mitigation Grant Program (HMGP), Building
Resilient Infrastructure and Communities (BRIC), and Flood Mitigation Assistance (FMA). This plan also aligns
with the planning elements of the National Flood Insurance Program’s Community Rating System (CRS) which
provides for lower flood insurance premiums in CRS communities.
1.2 BACKGROUND
A Hazard Mitigation Plan (HMP) is a living document that
communities use to reduce their vulnerability to hazards. It forms the
foundation for a community's long-term strategy to reduce disaster
losses and creates a framework for decision making to reduce damages
to lives, property, and the economy from future disasters. Examples of
mitigation projects include home acquisitions or elevations to remove
structures from high-risk areas, upgrades to critical public facilities,
and infrastructure improvements. Ultimately, these actions reduce
vulnerability, and communities are able to recover more quickly from
disasters. Galveston County has demonstrated its commitment to
reducing disaster losses by initially developing its multi-jurisdictional HMP in 2006 and updating information
upon which to base a successful mitigation strategy to reduce the impacts of natural disasters and to increase the
resiliency of its communities.
In response to the requirements of the Disaster Mitigation Act of 2000 (DMA 2000), which requires local
governmental agencies to develop and update their HMP every five years, this plan serves as the 2022 update to
the 2017 Galveston County HMP. During the course of the planning process, the entire plan was updated with
a focus on examining changes in vulnerability due to hazard events, reviewing local and county capabilities and
how they implement hazard mitigation, and reviewing the mitigation strategy and identifying new initiatives to
increase overall resiliency in the County.
1.3 PLAN ORGANIZATION
The Galveston County Hazard Mitigation Action Plan 2022 Update is organized as a two-volume plan and is in
alignment with the DMA planning requirements, the 2013 FEMA Local Mitigation Planning Handbook, and the
FEMA Local Mitigation Plan Review Tool.
Hazard Mitigation is any sustained
action taken to reduce or eliminate
the long-term risk and effects that can
result from specific hazards.
FEMA defines a Hazard Mitigation
Plan as the documentation of a state
or local government evaluation of
natural hazards and the strategies to
mitigate such hazards.
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2022 Update
Volume I provides information on the overall planning process and hazard profiling and vulnerability
assessments, which serves as a basis for understanding risk and identifying mitigation actions. As such, Volume
I is intended for use as a resource for on-going mitigation analysis.
Volume II provides an annex dedicated to each participating jurisdiction. Each annex summarizes the
jurisdiction’s legal, regulatory, and fiscal capabilities; identifies vulnerabilities to hazards; documents mitigation
plan integration with other planning efforts; records status of past mitigation actions; and presents an
individualized mitigation strategy. The annexes are intended to provide a useful resource for each jurisdiction
for implementation of mitigation projects and future grant opportunities, as well as a place for each jurisdiction
to record and maintain their local aspect of the countywide plan.
Figure 1-1. Galveston County Hazard Mitigation Planning Process
Volume I of this HMP includes the following sections:
Section 1: Introduction: Overview of the planning process and layout of the plan.
Section 2: Planning Process: Description of the HMP methodology and development process; Steering
Committee, Planning Committee, Planning Partnership, and stakeholder involvement efforts;
and a description of how this HMP will be incorporated into existing programs.
Section 3: County Profile: Overview of Galveston County, including: (1) physical setting, (2) land use,
(3) land use trends, (4) population and demographics, (5) general building stock and (6) critical
facilities and lifelines.
Section 4: Risk Assessment: Documentation of the hazard identification and hazard risk ranking process,
hazard profiles, and findings of the vulnerability assessment (estimates of the impact of hazard
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2022 Update
events on life, safety, health, general building stock, critical facilities, the economy);
description of the status of local data; and planned steps to improve local data to support
mitigation planning.
Section 5: Capability Assessment: A summary and description of the existing plans, programs, and
regulatory mechanisms at all levels of government (federal, state, county, local) that support
hazard mitigation within the County.
Section 6: Mitigation Strategy: Provides information regarding the mitigation goals and objectives in
response to priority hazards of concern and the process by which Galveston County and local
mitigation strategies have been developed or updated.
Section 7: Plan Maintenance Procedures: System established to continue to monitor, evaluate, maintain,
and update the HMP.
Volume II of this plan includes the following sections:
Section 8: Planning Partnership: Description of the planning partnership, their responsibilities, and
description of jurisdictional annexes.
Section 9: Jurisdictional Annexes: Jurisdiction-specific annex for Galveston County and each
participating jurisdiction containing their hazards of concern, hazard ranking, capability
assessment, mitigation actions, action prioritization specific only to Galveston County or that
jurisdiction, progress on prior mitigation activities (as applicable), and a discussion of prior
local hazard mitigation plan integration into local planning processes.
Appendices include the following:
Appendix A: Plan Adoption: Resolutions from the County and each jurisdiction included as each formally
adopts the HMP update.
Appendix B: Participation Documentation: Matrix to give a broad overview of who attended meetings and
when input was provided to the HMP update, as well as Letters of Intent to Participate described
in Section 2 (Planning Process), annex sign-off sheets discussed in Section 6 (Mitigation
Strategy) and additional worksheets submitted during workshops conducted throughout the
planning process.
Appendix C: Meeting Documentation: Agendas, attendance sheets, minutes, and other documentation (as
available and applicable) of planning meetings convened during the development of the plan.
Appendix D: Public and Stakeholder Outreach Documentation: Documentation of the public and stakeholder
outreach effort including webpages, informational materials, public and stakeholder meetings
and presentations, surveys, and other methods used to receive and incorporate public and
stakeholder comment and input to the plan process.
Appendix E: Mitigation Strategy Supplementary Data: Documentation of the broad range of actions
identified during the mitigation process; types of mitigation actions; the mitigation catalog
developed using jurisdiction input and potential mitigation funding sources.
Appendix F: Plan Maintenance Tools: Examples of plan review tools and templates available to support
annual plan review.
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Appendix G: Linkage Procedures: Procedures for non-participating local governments to "link" to the plan
within the period of performance to gain eligibility for programs under the DMA 2000.
Appendix H: Critical Facilities: Includes a full list of critical facilities identified for the update of the HMP.
Due to the sensitive nature of the information, critical facility details have been redacted.
1.4 THE UPDATED PLAN – WHAT IS DIFFERENT?
Galveston County’s initial HMP was approved by FEMA and adopted in 2006. Since then, it’s been updated in
2011 and 2016. The 2022 update builds on the previous plans and includes the following changes or
enhancements:
• Updated data and tools provided for a more detailed and accurate risk assessment. The risk assessment
was prepared to better support future grant applications by providing risk and vulnerability information
that would directly support the measurement of “cost-effectiveness” required under FEMA mitigation
grant programs.
• The plan identified implementable actions, with enough information to serve as the basis for policy and
funding decisions and represent measurable impacts on resiliency and mitigation progress. Strategies
provide direction, but actions are fundable under grant programs.
• Each participating jurisdiction has their own jurisdictional annex in the plan, found in Volume II,
Section 9.
Table 1-1. Plan Changes Crosswalk
44 CFR Requirement 2017 Plan 2022 Updated Plan
Requirement §201.6(b): In order to
develop a more comprehensive approach
to reducing the effects of natural disasters,
the planning process shall include:
(1) An opportunity for the public to
comment on the plan during the
drafting stage and prior to plan
approval.
(2) An opportunity for neighboring
communities, local and regional
agencies involved in hazard
mitigation activities, and agencies
that have the authority to regulate
development, as well as businesses,
academia, and other private and non-
profit interests to be involved in the
planning process; and
(3) Review and incorporation, if
appropriate, of existing plans,
studies, reports, and technical
information.
The 2017 plan followed an outreach
strategy utilizing multiple media
developed and approved by the
Steering Committee. This strategy
involved the following:
• Public participation on an
oversight Steering Committee.
• All Planning Partnership
meetings were open to the
public.
• Advertisements, social media
posts, and flyers were distributed
to gain public input.
• Use of a public mitigation
survey.
• Stakeholders were identified and
coordinated with throughout the
process.
Building upon the success of the 2017
plan, the 2022 planning effort
deployed the same public engagement
methodology. The plan included the
following enhancements:
• Using social media.
• Web-deployed survey.
As with the 2017 plan, the 2022
planning process identified key
stakeholders and coordinated with
them throughout the process. A
comprehensive review of relevant
plans and programs was performed
by the planning team.
§201.6(c)(2): The plan shall include a risk
assessment that provides the factual basis
for activities proposed in the strategy to
reduce losses from identified hazards.
Local risk assessments must provide
sufficient information to enable the
jurisdiction to identify and prioritize
appropriate mitigation actions to reduce
losses from identified hazards.
The 2017 plan included a risk
assessment of hazards of concern. It
looked at assets exposed to the hazard,
vulnerability, frequency of occurrence,
warning time, geographic extent,
potential impact, and hazard summary.
The 2022 plan update includes a
comprehensive update to the risk
assessment. The flood hazard was
expanded to include urban flooding
(or flooding outside of the
floodplain). New and updated hazards
of concern were included. The hazard
ranking methodology was adjusted
and includes adaptive capacity and
climate change. Jurisdiction-specific
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44 CFR Requirement 2017 Plan 2022 Updated Plan
risk assessment results are
summarized in Section 4 (Risk
Assessment) and in each
jurisdictional annex (Section 9).
§201.6(c)(2)(i): [The risk assessment]
shall include a] description of the …
location and extent of all-natural hazards
that can affect the jurisdiction. The plan
shall include information on previous
occurrences of hazard events and on the
probability of future hazard events.
The 2017 plan presented a risk
assessment of each hazard of concern.
Each section included the following:
• Hazard description
• Location
• Extent
• Historical occurrences
• Probability of future events
• Vulnerability assessment and
impact
A similar format, using new and
updated data, was used for the 2022
plan update. Each section of the risk
assessment includes the following:
• Hazard profile, including maps
of extent and location, previous
occurrences, and probability of
future events.
• Climate change impacts on
future probability.
• Vulnerability assessment
including impact on life, safety,
and health, general building
stock, critical facilities, and the
economy, as well as future
changes that could impact
vulnerability.
• The vulnerability assessment
also includes changes in
vulnerability since the 2017 plan.
§201.6(c)(2)(ii): [The risk assessment]
shall include a] description of the
jurisdiction’s vulnerability to the hazards
described in paragraph (c)(2)(i). This
description shall include an overall
summary of each hazard and its impact on
the community.
Vulnerability was assessed for all
hazards of concern. Each hazard of
concern included a summary of assets
exposed to the hazard (people/parcels
annualized losses and expected
damage to critical facilities).
A robust vulnerability assessment
was conducted for the 2022 plan
update, using new and updated asset
and hazard data. Volume 1, Section
4.3 summarizes countywide and
municipal-specific vulnerability for
each hazard of concern. The
jurisdictional annexes (Section 9)
include a summary table of impacts
on each community.
§201.6(c)(2)(ii): [The risk assessment]
must also address National Flood
Insurance Program insured structures that
have been repetitively damaged floods.
A summary of NFIP insured properties
including an analysis of repetitive loss
property locations was included in the
plan.
The resolution of the RL data
accessible by the County to support
this planning effort was limited by
FEMA’s Privacy Act Policies and the
time associated with processing the
requisite Information Sharing Access
Agreement (ISAA).
Requirement §201.6(c)(2)(ii)(A): The plan
should describe vulnerability in terms of
the types and numbers of existing and
future buildings, infrastructure and
critical facilities located in the identified
hazard area.
A complete inventory of the numbers
and types of buildings exposed was
generated for each hazard of concern.
The Steering Committee defined
“critical facilities” for the planning
area, and these were inventoried by
exposure.
Quantitative and qualitative analyses
were conducted using the updated
hazard and inventory data as
presented in Section 4 (Risk
Assessment). In addition, critical
facilities considered lifelines in
accordance with FEMA’s definition
were identified.
Requirement §201.6(c)(2)(ii)(B): [The
plan should describe vulnerability in terms
of an] estimate of the potential dollar
losses to vulnerable structures identified in
paragraph (c)(2)(i)(A) and a description
of the methodology used to prepare the
estimate.
Loss estimates were generated for all
hazards of concern by using readily
available information.
Quantitative and qualitative analyses
were conducted using the updated
hazard and inventory data as
presented in Section 4 (Risk
Assessment). Estimated potential
losses are reported in both Volume 1,
Section 4.3, and Volume II Section 9
for each jurisdiction.
Requirement §201.6(c)(2)(ii)(C): [The
plan should describe vulnerability in terms
of] providing a general description of land
There is a summary of anticipated
development in the Community
profile.
A spatial analysis using identified
growth areas, and potential new
development identified by
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uses and development trends within the
community so that mitigation options can
be considered in future land use decisions.
municipalities was conducted to
determine if located in hazard areas.
These results were reported to all
participants and summarized in their
annexes to discuss mitigation
measures. In Volume I, Section 4.3,
projected changes in population and
development are discussed in each
hazard section and how these
projected changes may lead to
increased vulnerability, or
plans/regulations/ordinances in place
to implement mitigation to protect the
development.
§201.6(c)(3):[ The plan shall include a
mitigation strategy that provides the
jurisdiction’s blueprint for reducing the
potential losses identified in the risk
assessment, based on existing authorities,
policies, programs and resources, and its
ability to expand on and improve these
existing tools.]
The 2017 plan contained goals,
objectives, and actions. The identified
actions covered multiple hazards,
goals, and objectives.
The Steering Committee reviewed
and updated the goals and objectives,
and they were approved by the
Planning Committee. A mitigation
strategy workshop with associated
tools and guidance on problem
statement development was deployed
to inform the identification of
mitigation actions. Actions that were
completed or no longer considered to
be feasible were removed; and
actions considered general or
capabilities were moved to the
capability and integration sections.
The balance of the actions was
carried over to the 2022 plan, and in
some cases, new actions were added
to the action plan.
Requirement §201.6(c)(3)(i): [The hazard
mitigation strategy shall include a]
description of mitigation goals to reduce
or avoid long-term vulnerabilities to the
identified hazards.
The Steering Committee identified
goals and objectives targeted
specifically for this hazard mitigation
plan. These planning components
supported the actions identified in the
plan.
The Steering Committee reviewed
and updated the goals and objectives
and they were approved by the
Planning Committee. Several new
objectives were identified to align
with updated County and municipal
priorities.
Requirement §201.6(c)(3)(ii): [The
mitigation strategy shall include a] section
that identifies and analyzes a
comprehensive range of specific mitigation
actions and projects being considered to
reduce the effects of each hazard, with
particular emphasis on new and existing
buildings and infrastructure.
For each identified hazard, goals and
objectives were provided as part of the
mitigation strategy. The strategies
were compiled into categories
depending on the hazard they are
related to. The strategies were then
prioritized.
For the 2022 update, a mitigation
catalog was developed to provide a
comprehensive range of specific
mitigation actions to be considered. A
table with the analysis of mitigation
actions by type and hazard was used
in jurisdictional annexes to the plan.
Mitigation action worksheets with an
alternative project evaluation were
prepared for FEMA-eligible projects.
Requirement: §201.6(c)(3)(ii): [The
mitigation strategy] must also address the
jurisdiction’s participation in the National
Flood Insurance Program, and continued
compliance with the program’s
requirements, as appropriate.
Each municipality identified an action
stating their commitment to maintain
compliance and good standing under
the program.
Each municipality identified an action
stating their commitment to maintain
compliance and good standing under
the program.
Requirement: §201.6(c)(3)(iii): [The
mitigation strategy shall describe] how the
actions identified in section (c)(3)(ii) will
be prioritized, implemented, and
administered by the local jurisdiction.
Prioritization shall include a special
Each recommended action was
prioritized using a qualitative
methodology based on the objectives
the project will meet, the timeline for
completion, how the project will be
funded, the impact of the project, the
A revised methodology based on the
STAPLEE criteria and using new and
updated data was used for the 2022
plan update. The 14 criteria were
used to evaluate each potential
mitigation action. The evaluation
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44 CFR Requirement 2017 Plan 2022 Updated Plan
emphasis on the extent to which benefits
are maximized according to a cost benefit
review of the proposed projects and their
associated costs.
benefits of the project, and the costs of
the project.
included a qualitative benefits and
cost review. The results of the
evaluation were used to identify the
actions to include in the plan and
assist with the prioritization.
Requirement §201.6(c)(4)(i): [The plan
maintenance process shall include a]
section describing the method and
schedule of monitoring, evaluating, and
updating the mitigation plan within a five-
year cycle.
The 2017 plan details a plan
maintenance strategy stating that the
plan will be revised and maintained as
required.
The 2022 plan details a plan
maintenance strategy similar to that
of the initial plan.
Requirement §201.6(c)(4)(ii): [The plan
shall include a] process by which local
governments incorporate the requirements
of the mitigation plan into other planning
mechanisms such as comprehensive or
capital improvement plans, when
appropriate.
The 2017 plan details
recommendations for incorporating the
plan into other planning mechanisms.
The 2022 plan details
recommendations for incorporating
the plan into other planning
mechanisms such as the following:
• Comprehensive/Master Plan.
• Emergency Response Plan/
Emergency Operations Plan.
• Capital Improvement Programs.
• Municipal Code.
Requirement §201.6(c)(4)(iii): [The plan
maintenance process shall include a]
discussion on how the community will
continue public participation in the plan
maintenance process.
The 2017 plan details a strategy for
continuing public involvement.
The 2017 plan maintenance strategy
was carried over to the 2022 plan.
Requirement §201.6(c)(5): [The local
hazard mitigation plan shall include]
documentation that the plan has been
formally adopted by the governing body of
the jurisdiction requesting approval of the
plan (e.g., City Council, County
Commissioner, Tribal Council).
The County and participating
jurisdictions adopted the 2017 HMP.
The 2022 plan achieves DMA
compliance for Galveston County and
all participating jurisdictions.
Resolutions for each partner adopting
the plan can be found in Appendix A
of this volume.
SECTION 2: PLANNING PROCESS
Galveston County, TX | Hazard Mitigation Plan 2-1
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SECTION 2. PLANNING PROCESS
2.1 INTRODUCTION
This section includes a description of the planning process used to update the 2022 Galveston County, Texas
Hazard Mitigation Plan (HMP, also referred herein as the Hazard Mitigation Plan or the plan), including how
it was prepared, who was involved in the process, and how the public was involved. To ensure that the plan
meets requirements of the DMA 2000 and that the planning process would have the broad and effective support
of the County, regional and local stakeholders, and the public, an approach to the planning process and plan
documentation was developed to achieve the following:
• The HMP is multi-jurisdictional and considers natural and human-caused hazards facing Galveston
County, thereby satisfying the natural hazards mitigation planning requirements specified in the DMA
2000.
• Galveston County invited all municipalities in the County to join with them in the preparation of the
Galveston County HMP. The County and all municipalities are participating in the HMP as indicated
in Table 2-1 below.
• The HMP was developed following the process outlined by the DMA 2000, FEMA regulations, and
prevailing FEMA and TDEM guidance. Following this process ensures all the requirements are met
and support HMP review
Table 2-1. Participating Galveston County Jurisdictions
Jurisdictions
Galveston County
Bayou Vista (C) Kemah (C)
Clear Lake Shores (C) La Marque (C)
Dickinson (C) League City (C)
Friendswood (C) Santa Fe (C)
Hitchcock (C) Tiki Island (V)
Jamaica Beach (C)
The Galveston County HMP update was written using the best available information obtained from a wide
variety of sources. Throughout the HMP update process, a concerted effort was made to gather information from
municipal and regional agencies and staff, as well as stakeholders, federal and state agencies, and the residents
of the County. The Steering Committee solicited information from local agencies and individuals with specific
knowledge of certain hazards and past historical events. In addition, the Steering Committee took into
consideration planning and zoning codes, ordinances, and recent land use planning decisions. The hazard
mitigation strategies identified in this HMP update were developed through an extensive planning process
involving local, county, and regional agencies, residents, and stakeholders.
This section of the plan describes the mitigation planning process, including (1) Organization of the Planning
Process; (2) Stakeholder Outreach and Involvement; (3) Integration of Existing Data, Plans, and Technical
Information; (4) Integration with Existing Planning Mechanisms and Programs; and (5) Continued Public
Involvement.
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2.2 ORGANIZATION OF THE PLANNING PROCESS
Many parties supported the preparation of this HMP update: County officials, municipal officials, the Ste ering
Committee, Planning Partnership, stakeholders, and planning consultant. This planning process does not
represent the start of hazard risk management in the County; rather it is part of an ongoing process that various
State, County and local agencies and individuals have continued to embrace. A summary of the past and ongoing
mitigation efforts is provided in Section 6 (Mitigation Strategy), as well as in Volume II Section 9 (Jurisdictional
Annexes), to give an historical perspective of the County and local activities implemented to reduce vulnerability
to hazards in the planning area.
This section of the plan identifies how the planning process was organized with the many planning partners
involved and outlines the major activities that were conducted in the development of this HMP update.
2.2.1 Organization of Planning Partnership
Recognizing the need to manage risk within the County, and to meet the requirements of the DMA 2000, the
Galveston County Office of Emergency Management led the update to the 201 7 Galveston County HMP. On
March 18, 2020, Galveston County Office of Emergency Management signed the Grantee-Subgrantee
Agreement (PDMC-PL-06-TX-2019-010) between the State of Texas and Galveston County for funds to update
the Galveston County HMP. The period of performance for this grant is from October 1, 2018 and ending April
1, 2022.
Project management and grant administration has been the responsibility of the Galveston County Office of
Emergency Management. The County has been proactive in supporting natural hazard mitigation. This update
supported implementation of projects, provided the basis of the initial mitigation strategy update, and formed
problem statements to focus efforts on identifying high priority mitigation projects to reduce vulnerability to
hazards of concern for the planning area.
The County selected a contract planning consultant (Tetra Tech Inc. – Parsippany, NJ) to guide the County and
participating jurisdictions through the HMP update process. A contract between Tetra Tech Inc. (Tetra Tech)
and the County was executed in August 2021. Specifically, Tetra Tech, the “contract consultant”, was tasked
with:
• Assisting with the organization of a Steering Committee and Planning Partnership.
• Assisting with the development and implementation of a public and stakeholder outreach program.
• Data collection.
• Facilitation and attendance at meetings (Steering Committee, Planning Partnership, stakeholder, public
and other).
• Review and update of the hazards of concern, and hazard profiling and risk assessment.
• Assistance with the review and update of mitigation planning goals and objectives.
• Assistance with the review of progress of past mitigation strategies.
• Assistance with the screening of mitigation actions and the identification of appropriate actions.
• Assistance with the prioritization of mitigation actions.
• Authoring of the draft and final HMP documents.
On September 20, 2021, Galveston County Office of Emergency Management notified all municipalities within
the County of the pending planning process and invited them to formally participate. Municipalities were
provided with a copy of the Planning Partner Expectations and asked to formally notify the County of their intent
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to participate. Section 9 (Jurisdictional Annexes) and Appendix B (Participation Documentation) detail
contributions provided by the municipality.
To facilitate HMP development, with support from their contract planning consultant, Galveston County
developed a Steering Committee to provide guidance and direction to the planning effort, and to ensure the
resulting document will be embraced both politically and by the constituency within the planning area. The
Steering Committee consisted of county and local officials (refer to Table 2-2 for a list of Steering Committee
members). Specifically, the Steering Committee was charged with: Providing guidance and overseeing the
planning process on behalf of the general planning partnership.
• Attending and participating in Steering Committee meetings.
• Establish a timeline for completion of the plan.
• Assisting with the development and completion of certain planning elements, including:
• Reviewing and updating the hazards of concern,
• Developing a public and stakeholder outreach program,
• Assuring that the data and information used in the plan update process is the best available
• Reviewing and updating the hazard mitigation goals and objectives,
• Identification and screening of appropriate mitigation strategies and activities; and
• Reviewing and commenting on plan documents prior to submission to TDEM and FEMA.
• Ensure that the plan meets the requirements of DMA 2000, FEMA, and TDEM guidance.
• The organizational structure was successfully implemented for the 2022 HMP updated consistent with
the development of the initial 2017 planning process.
The Steering Committee provided guidance and leadership, oversight of the planning process, and acted as the
point of contact for all participating jurisdictions and the various interest groups in the planning area. The
members of the Steering Committee worked to maintain continuity of the process throughout the process, to
overcome the issues created by the COVID-19 pandemic.
Table 2-2. Steering Committee Members
Name Title Organization
Laura Norman Deputy Emergency Management Coordinator;
HMP Coordinator for Planning Process
Galveston County Office of Emergency
Management
James Gentile Director of Contract Services Galveston County Contract Services
Julie Diaz Director Galveston County Parks and Cultural Services
Lee Crowder Road Administrator Galveston County Roads and Bridges
Martha Lee Assistant Director Galveston County Parks and Cultural Services
Michael Shannon County Engineer Galveston County Engineering & Right of Way
Randy Valcin Director of Public Health Surveillance Galveston County Health District
William Riordan Facilities Director Galveston County Facilities
As part of the initial outreach to each municipality, the County outlined the planning partner expectations that
outlined the responsibilities of the participants and asked each municipality to respond to Galveston County
OEM if they wish to participate. By agreeing to Galveston County, each municipality authorized the Steering
Committee to represent the municipality in the completion of certain portions of the planning elements. All
municipalities in the County agreed to participate. Table 2-3 lists the current members of the Steering
Committee, at the time of this HMP’s publication. Please note that Steering Committee members are also part
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of the overall project Planning Partnership, fulfilling these responsibilities on behalf of Galveston County. This
planning partnership (Steering and Planning Committees) were charged with the following:
• Represent their jurisdiction throughout the planning process and assure participation expectations are
met by their community.
• Assure participation of all department and functions within their jurisdiction that have a stake in
mitigation (e.g., planning, engineering, code enforcement, police and emergency services, public
works).
• Assist in gathering information for inclusion in the HMP update, including the use of previously
developed reports and data.
• Support and promote the public involvement process.
• Report on progress of mitigation actions identified in prior or existing HMPs, as applicable.
• Identify, develop, and prioritize appropriate mitigation initiatives.
• Report on progress of integration of prior or existing HMPs into other planning processes and municipal
operations.
• Develop and author a jurisdictional annex for their jurisdiction.
• Review, amend, and approve all sections of the plan update when requested.
• Adopt, implement, and maintain the plan update
Table 2-3. Galveston County Hazard Mitigation Planning Partnership (Steering Committee and
Municipalities)
Jurisdiction Name Title Jurisdiction Representative Steering Committee Galveston County Office of
Emergency Management Laura Norman Deputy Emergency Management Coordinator;
HMP Coordinator for Planning Process X
Galveston County Contract
Services James Gentile Director of Contract Services X
Galveston County Parks and
Cultural Services
Julie Diaz Director X
Martha Lee Assistant Director X
Galveston County Roads and
Bridges Lee Crowder Road Administrator X
Galveston County Engineering &
Right of Way Michael Shannon County Engineer X
Galveston County Health District Randy Valcin Director of Public Health Surveillance X
Galveston County Facilities William Riordan Facilities Director X
Bayou Vista (C) Jimmie Gillane Emergency Management Coordinator X
Clear Lake Shores (C) Brent Spiers City Admin/EMC X
Dickinson (C) Greg Trantham Co-Emergency Mgt Coordinator X
Derek Hunt Co-Emergency Mgt Coordinator X
Friendswood (C) Steven Simmons Deputy Fire Marshal X
Hitchcock (C) Wilmon Smith Police Chief X
Arnie Cross Director of Community Development X
Jamaica Beach (C) Brad Heiman Police Chief X
Kemah (C) Walter Gant Emergency Management Coordinator X
La Marque (C) Kyle Hunter Emergency Management X
League City (C) Ryan Edghill Emergency Management X
Santa Fe (C) Bobby Shores Police Captain X
Tiki Island (V) Graham George Emergency Management Coordinator X
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Ultimately, jurisdictional participation is evidenced by a completed annex (chapter) of the HMP (Section 9)
wherein the jurisdictions have identified their planning points of contact, evaluated their risk to the hazards of
concern, identified their capabilities to effect mitigation in their community, and identified and prioritized an
appropriate suite of mitigation initiatives, actions, and projects to mitigate their natural hazard risk; and
eventually by the adoption of the updated plan via resolution.
Appendix B (Participation Documentation) identifies those individuals who represented their jurisdictions
during this planning effort and indicates how they contributed to the planning process. This matrix is intended
to give a broad overview of who attended meetings and when input was provided. All participants were
encouraged to attend the Kick-off Meeting, Risk Assessment Meeting, and Mitigation Action Workshop. During
the planning process the planning consultant contacted each participant to offer support, explain the process,
meet individually to collect updated information and to facilitate the submittal and review of critical documents.
All municipalities actively participate in the National Flood Insurance Program (NFIP) and have designated
NFIP Floodplain Administrators (FPA). All known FPAs were informed of the planning process, were provided
the opportunity to review the plan including the jurisdictional annex and provide direct input to the plan update.
Local FPAs are identified in the Administrative and Technical portions of the jurisdictional annexes in Section
9 (Jurisdictional Annexes).
2.2.2 Planning Activities
Members of the Planning Partnership (individually and as a whole), as well as key stakeholders, convened and/or
communicated regularly to share information and participate in workshops to identify hazards; assess risks;
review existing inventories of and identify new critical facilities; assist in updating and developing new
mitigation goals and strategies; and provide continuity through the process to ensure that natural hazards
vulnerability information and appropriate mitigation strategies were incorporated. All members of the Steering
Committee and Planning Partnership had the opportunity to review the draft plan and supported interaction with
other stakeholders and assisted with public involvement efforts.
A summary of committee meetings (Steering Committee and Planning Partnership) held and key milestones met
during the development of the HMP update is included in Table 2-4 that also identifies which DMA 2000
requirements the activities satisfy. Documentation of meetings (e.g., agendas, sign-in sheets, meeting notes) are
in Appendix C (Meeting Documentation). Table 2-4 identifies only the formal meetings held during plan
development and does not reflect all planning activities conducted by individuals and groups throughout the
planning process. In addition to these meetings, there was a great deal of communication between the County,
committee members, and the contract consultant through individual local meetings, electronic mail (email), and
by phone.
Table 2-4. Summary of Mitigation Planning Activities and Efforts
Date
DMA 2000
Requirement Description of Activity Participants
September 10,
2021 2
Pre-Kick Off Meeting with County: Plan
timing and administration; Data needs and
sharing; Hazards of concern; Dates and next
steps
County OEM, Tetra Tech
September 16,
2021 2
Steering Committee Meeting #1:
Introduce Steering Committee to the HMP
update process, discuss mitigation planning,
project organization, roles and
responsibilities, data collection, hazards of
concern, and schedule of plan.
County OEM, County Engineer, County
Roads and Bridges, County Parks, County
Facilities, and Tetra Tech
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Date
DMA 2000
Requirement Description of Activity Participants
September 20,
2021 2 All municipalities invited to participate in
the planning process
Galveston County OEM, all municipal
governments
September 29,
2021 2, 1a, 1b
Municipal Kick-Off Meeting/ Planning
Partnership Meeting #1: open to the public
Introduce Planning Partnership to the HMP
update process, discuss mitigation planning,
project organization, roles and
responsibilities, data collection, hazards of
concern, HMP update process and
municipal worksheets, and schedule of plan.
Galveston County, Bayou Vista, City of
Clear Lake Shores, City of Dickinson, City
of Hitchcock, City of La Marque, League
City, Santa Fe, Tiki Island, Gulf Coast
Center, City of Texas, Port of Texas
Security Council, National Weather
Service, Bolivar Peninsula Special Utility
District, Clear Creek Independent School
District, Dallas Independent School
District, Texas City Independent School
District, Texas A&M University at
Galveston, Friendswood Medical Outreach,
Tetra Tech
November 18,
2021 2, 4a
Steering Committee Meeting #2: Review
project schedule and status, hazards of
concern, critical facilities and lifelines,
goals, and objectives, SWOO exercise and
next steps
County OEM, County Roads and Bridges,
County Parks, County Contract Services,
County Health, Tetra Tech
December 2,
2021 2, 4a, 4b
Mitigation Action Workshop: Review
project schedule and status, hazards of
concern, critical facilities and lifelines,
goals, and objectives, SWOO exercise and
next steps.
County OEM, Galveston County,
Galveston County Engineering Department,
Friendswood, Jamaica Beach, La Marque,
League City, Santa Fe, Tetra Tech
December 21,
2021
2, 3a, 3b, 3c,
3d, 3e
Risk Assessment Presentation: Review
project schedule and status, present risk
ranking, and go over how to review and
provide input
County OEM, Tetra Tech
January 25,
2022 2
Draft Plan Review Presentation: Overview
of entire plan and sections; confirmed plan
maintenance schedule
County OEM, Dickinson, Clear Lake
Shores, League City, Jamaica Beach, Santa
Fe, Friendswood, Congressman Weber’s
Office, and Tetra Tech
TBD 1b, 2
Draft HMP posted to public project website;
all plan participants were notified and asked
to assist with the public outreach including
social media. Neighboring counties and
stakeholders were notified of the posting as
well.
Public and Stakeholders
TBD 2 HMP submitted to TDEM and FEMA
Region VI TDEM, FEMA Region VI
Upon plan
approval by
FEMA
1a
Plan adoption by resolution by the
governing bodies of all participating
municipalities
All Plan Participants
Note: All activities/efforts were conducted during the National Emergency response to the COVID-19 pandemic.
TBD = to be determined.
Each number in column 2 identifies specific DMA 2000 requirements, as follows:
1a – Prerequisite – Adoption by the Local Governing Body
1b – Public Participation
2 – Planning Process – Documentation of the Planning Process
3a – Risk Assessment – Identifying Hazards
3b – Risk Assessment – Profiling Hazard Events
3c – Risk Assessment – Assessing Vulnerability: Identifying Assets
3d – Risk Assessment – Assessing Vulnerability: Estimating Potential Losses
3e – Risk Assessment – Assessing Vulnerability: Analyzing Development Trends
4a – Mitigation Strategy – Local Hazard Mitigation Goals
4b – Mitigation Strategy – Identification and Analysis of Mitigation Measures
4c – Mitigation Strategy – Implementation of Mitigation Measures
5a – Plan Maintenance Procedures – Monitoring, Evaluating, and Updating the Plan
5b – Plan Maintenance Procedures – Implementation through Existing Programs
5c – Plan Maintenance Procedures – Continued Public Involvement
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2.3 STAKEHOLDER OUTREACH AND INVOLVEMENT
Stakeholders are the individuals, agencies, and jurisdictions that have a vested interest in the recommendations
of the HMP, including all planning partners. Diligent efforts were made to assure broad regional, county, and
local representation in this planning process. To that end, a comprehensive list of stakeholders was develop ed
with the support of the Planning Partnership. Stakeholder outreach was performed early on, and continually
throughout the planning process. However, due to the limitations on participation posed by the pandemic and
the strains on time and resources for many local governments and other community organizations starting in
2020 through present, participation of stakeholders at the municipal level was limited. In accordance with FEMA
guiding principles for inclusive participation at various levels, the planning team will place a high priority on an
expanded effort on stakeholder participation with local planning committees in future plan updates.
This subsection discusses the various stakeholders that were invited to participate in the development of this
HMP update, and how these stakeholders participated and contributed. This summary listing cannot possibly
represent the total of stakeholders that were aware of and/or contributed to this HMP update, as outreach efforts
were being made, both formally and informally, throughout the process by the many planning partners involved
in the effort, and documentation of all such efforts is impossible. Instead, this summary is intended to
demonstrate the scope and breadth of the stakeholder outreach efforts made during the plan update process:
• All Planning Partnership meetings were open to the public and advertised via the Galveston County
website (https://www.galvestoncountytx.gov/).
• Municipalities were provided outreach materials to post on their websites, social media platforms, and
distribute printed materials.
• Distributed a stakeholder survey and neighboring county survey to provide input regarding
vulnerabilities, capabilities, and mitigation projects.
• Posted draft plan on the Galveston County website and advertised using social media platforms.
• Email correspondence to regional stakeholders and neighboring counties to review the draft HMP and
provide input.
2.3.1 Federal, State, and County Agencies
The following describes the various departments and agencies that were involved during the planning process.
Federal Agencies
Please see Appendix B (Participation Documentation) for further details regarding federal agency participation.
All responses to the stakeholder surveys may be found in Appendix D (Public and Stakeholder Outreach).
FEMA Region VI: Provided updated planning guidance; conducted plan review.
National Weather Service (NWS): Provided information regarding hazard identification and the risk
assessment; attended planning partnership meetings. Additionally, the NWS provides weather briefings,
forecasts, and incident support to Galveston County. They provide live webinars to the County and
municipalities ahead of floods, hurricanes, and severe weather. They also support weather-sensitive incidents
including hazardous materials releases.
Information regarding hazard identification and the risk assessment for this plan update were requested and
received or incorporated by reference from the following agencies and organizations:
• National Climatic Data Center (NCDC)
• National Hurricane Center (NHC)
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• National Oceanic and Atmospheric Administration (NOAA)
• Storm Prediction Center (SPC)
• U.S. Army Corps of Engineers (USACE)
• U.S. Census Bureau
• U.S. Department of Agriculture (USDA)
• U.S. Department of Health and Human Services
• U.S. Environmental Protection Agency (USEPA)
• U.S. Geological Survey (USGS)
State Agencies
Please see Appendix B (Participation Documentation) for further details regarding state agency participation.
All responses to the surveys may be found in Appendix D (Public and Stakeholder Outreach).
Texas Division of Emergency Management (TDEM): Administered the planning grant; provided updated
planning guidance; provided review of the draft HMP update.
Texas Department of Transportation (TX DOT): Invited to attend planning partnership meetings and provide
input through the stakeholder survey.
County Departments
Several county departments were represented on the Steering Committee and involved in the HMP update
planning process. Appendix B (Participation Matrix) provides further details regarding regional and local
stakeholder agencies. All responses to the stakeholder surveys are in Appendix D (Public and Stakeholder
Outreach). Refer to Section 5 (Capability Assessment) for details on each department and their roles during the
HMP update and their overall responsibilities in Galveston County.
• Galveston County Office of Emergency Management
• Galveston County Contract Services
• Galveston County Parks and Cultural Services
• Galveston County Roads and Bridges
• Galveston County Engineering & Right of Way
• Galveston County Health District
• Galveston County Facilities
2.3.2 Regional and Local Stakeholders
All Planning Partnership meetings were announced on the Galveston County HMP project website and posted
on social media to invite residents and stakeholders. In addition, the County and municipal representatives
emailed regional and local stakeholders requesting their participation in stakeholder sector-specific surveys to
provide input on vulnerable assets, capabilities, and current/potential future mitigation projects; and invited to
provide input on the draft HMP. Refer to Appendix C (Participation Documentation) for further details regarding
regional and local stakeholder agency attendance at meetings and Appendix D for additional details on the public
and stakeholder outreach, including responses received to the surveys.
Academia
Schools, universities, and other academia institutions were invited to attend planning process meetings and asked
to complete the stakeholder survey. The following provided input in person or virtually at Planning Partnership
meetings, as well as through the County’s online stakeholder survey:
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• Clear Creek Independent School District
• Dickinson Independent School District
• Friendswood Independent School District
• Galveston College
• Galveston Independent School District
• High Island Independent School District
• Hitchcock Independent School District
• Santa Fe Independent School District
• Texas A&M University at Galveston
• Texas City Independent School District
• University of Texas Medical Branch
Business and Commercial Interests
Businesses and commercial industries in the County were invited to take the stakeholder survey and provide
input to the planning process. The following provided input in person or virtually at Planning Partnership
meetings, as well as through the County’s online stakeholder survey:
• Port of Texas City – attended planning partnership meetings
• Port of Galveston
Emergency Services
All state, county, and local emergency service providers (police, fire, and EMS) were invited to take the
stakeholder survey and provide input to the planning process. The following provided input in person or virtually
at Planning Partnership meetings, as well as through the County’s online stakeholder survey:
• Galveston County Emergency Communications District
• Galveston County Emergency Communications District #2
• Port of Texas City Security Council
• Santa Fe Fire and Rescue
• San Leon Volunteer Fire Department
Highway and Public Works
All state, county, and local highway and public works departments were notified of the Highway and Public
Work’s stakeholder survey and invited to provide input on the draft HMP. In addition, many of the participating
municipalities had representatives from their highway and public works departments representing them on the
planning partnership. The following provided input to the planning process via the County’s online stakeholder
survey:
• Galveston County Roads and Bridges – attended meetings
• Galveston County Engineering & Right of Way
• Galveston County Facilitates & Maintenance
• Galveston County Parks & Cultural Services
• Texas Department of Transportation
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Hospitals and Healthcare
All hospitals and healthcare facilities and providers located in County were invited to take the stakeholder survey
and provide input to the planning process. The following provided input in person or virtually at Planning
Partnership meetings, as well as through the County’s online stakeholder survey:
• Galveston County Health Department
• Galveston County Health District Office of Environmental Health Programs
• Gulf Coast Center
• University of Texas Medical Branch at Galveston
Utilities
Utility providers in the County were invited to take the stakeholder survey and provide input to the planning
process. The following provided input in person or virtually at Planning Partnership meetings, as well as through
the County’s online stakeholder survey:
• Bolivar Peninsula Special Utility District
• Gulf Coast Water Authority
• Galveston County Water Control and Improvement District #1
• Galveston County Water Control and Improvement District #19
Adjacent Counties
Galveston County has made an effort to keep surrounding counties and municipalities appraised of the project
and allowed the opportunity to provide input to this planning process. Specifically, the following adjoining and
nearby county representatives were contacted in September 2021 to invite them to provide input to the planning
process. In January 2022, they were invited to complete a neighboring county survey. In February 2022, they
were informed of the posting of the draft plan and invited to review and provide feedback. The following
provided input in person or virtually at Planning Partnership meetings, as well as through the County’s online
neighboring county survey:
• Brazoria County
• Chambers County
• Harris County – completed the survey and provided feedback regarding their involvement with
Galveston County.
2.3.3 Stakeholder Survey Summary
The following provides a summary of the results and feedback received by stakeholders who completed the
survey. Feedback was reviewed by the Steering Committee and integrated where appropriate in the plan.
Stakeholder Survey
The stakeholder survey was designed to help identify general needs for hazard mitigation and resiliency within
Galveston County from its perspective, as well as to identify specific projects that may be included in the
mitigation plan. It was distributed to identified stakeholders, including the various county and municipal
departments and agencies in the county. As of January 28, 2022, 8 stakeholders completed the survey, 40% of
which in the emergency services category, 20% in academic/research, 20% in public work, and 20% in utilities.
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Hazard and Damage Identification
Half of respondents said the buildings/facilities/structures they have worked in and/or are responsible for have
been impacted by a hazard; 25% said no and 25% were unsure. Those that experienced damage stated that the
structures had wind and flood damage from hurricanes, with some reporting complete destruction of buildings.
When asked what areas are most vulnerable to hazards in the County, answers included storm surge flooding,
hazardous material releases, flooding from heavy rainfall, structures not built to withstand hurricane impacts,
exposed water lines, and road/underpass flooding. Over 60% of respondents believe the faci lities and
infrastructure for their organization are equipped to handle a disaster and/or are resilient to damages; 25% sa id
no; and 12/5% says maybe.
Community Preparedness
A majority of respondents (75%) stated that their organization has an emergency operations plan. Half of the
respondents stated they are covered by a Continuity of Operations Plan, a Continuity of Government Plan. One
respondent indicated that they have risk and vulnerability assessments and one was unsure of what plans are
available in their organization.
Figure 2-1. Plans of Stakeholders
Project Identification
Respondents identified the following projects or programs that could reduce their organization’s vulnerability to
damages, including operation of service:
• Reduce vulnerability to water systems
• Storage and emergency operations building to place equipment and materials prior to a hurricane or
other event to allow for access during the event
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• Relocating water lines to reduce risk of line being severed during a storm
• Improvements to drainage systems
The following were identified as recently implemented projects that reduced vulnerabilities to hazard events:
• Elevated operations center in Dickinson
• Elevated 1-million-gallon storage tank to provide drinking water during power outages or damages
Respondents were also asked to detail how their organization has been involved in response to the ongoing
COVID-19 pandemic. Respondents detailed the following:
• Weather briefings to support outdoor testing and vaccination operations
• Testing, vaccinations, contact tracing, and data collection
• Providing potable water throughout the pandemic
• Testing center for fire, police, EMS, and municipal employees
• Emotional support and resources
The following services and infrastructure needs were identified by respondents as needing to be built or improved
upon within their communities in order to mitigate damages experienced by the pandemic:
• Crew living quarters
• Air filtration systems
• Water and wastewater operations
Neighboring County Survey
The neighbor survey was sent to the surrounding counties of Galveston County due to the ir proximity to and
because effects of hazard events that impact Galveston County would be similar to that of their neighbors. As
of January 28, 2022, one county completed the survey. The respondent stated Galveston County is involved in
their county’s comprehensive emergency operations planning. Together, they are part of UASI, HGAC, MACC
and various hurricane and evacuation plans. During emergency operations and disaster response, the counties
communicate through conference calls, MACC, and mutual aid requests. They are also part of an evacuation
hub plan.
2.4 PUBLIC PARTICIPATION – RESIDENT INVOLVEMENT
In order to facilitate better coordination and communication between the Planning Partnership and residents and
to involve the public in the planning process, it was determined that meeting dates/locations will be made
available to the public via the Galveston County website and social media outlets. The participating partners
also feel that community input on the HMP will increase the likelihood of hazard mitigation becoming one of
the standard considerations in the evolution and growth of the County.
The Planning Partnership has made the following efforts toward public participation in the development and
review of the HMP:
• All hazard mitigation planning meetings that were open to the public were advertised on the Galveston
County website.
• An on-line natural hazards preparedness public survey was developed to gauge household preparedness
relevant to hazards in the Galveston County and to assess the level of knowledge of tools and techniques
to assist in reducing risk and loss of those hazards. The questionnaire asks quantifiable questions about
citizen perception of risk, knowledge of mitigation, and support of community programs. The
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questionnaire also asks several demographic questions to help analyze trends. The questionnaire was
advertised via social media and available for two months to facilitate public input garnering over 140
responses. The survey results were provided to the Steering Committee to use to identify vulnerabilities
and develop mitigation strategies. A summary of survey results is provided in Appendix D (Public and
Stakeholder Outreach) of this plan.
• Results from the natural hazards preparedness survey were used to inform the action plans of the
planning partners. To address the most requested types of projects that residents wanted local and county
agencies to be doing, many planning partners included actions to improve and strengthen infrastructure,
improve the damage resistance of utilities, buy out flood prone properties, improve protective structures,
and provide greater control over development in high hazard areas.
• All plan participants were requested to advertise the public survey via local homepage links, and other
available public announcement methods (e.g., Facebook, Twitter, email blasts). Refer to Appendix D
which highlights these local efforts.
• Starting in February 2022, draft sections of the plan (as available) were posted on the County’s website
for public review and comment.
• Once approved by TDEM/FEMA, the final HMP will be available on the County website.
2.5 INCORPORATION OF EXISTING PLANS, STUDIES, REPORTS, AND
TECHNICAL INFORMATION
The Galveston County HMP strives to use the best available technical information, plans, studies, and reports
throughout the plan process to support hazard profiling; risk and vulnerability assessment; review and evaluation
of mitigation capabilities; and the identification, development, and prioritization of county and local mitigation
strategies.
The asset and inventory data used for the risk and vulnerability assessments is presented in the County Profile
(Section 3). Details of the source of this data, along with technical informati on on how the data was used to
develop the risk and vulnerability assessment, is presented in the Risk Assessment, specifically in Section 4.1
Methodology and Tools, as well as throughout the hazard profiles in Section 4.3 (Hazard Profiles).
Plans, reports, and other technical information were identified and provided directly by the County, participating
jurisdictions, and numerous stakeholders involved in the planning effort, as well as through independent research
by the planning consultant. The County and participating jurisdictions were tasked with updating the inventory
of their Planning and Regulatory capabilities in Section 9 (Jurisdictional Annexes) and providing relevant
planning and regulatory documents, as applicable. Relevant documents, including plans, reports, and ordinances
were reviewed to identify the following:
• Existing County and municipal capabilities.
• Needs and opportunities to develop or enhance capabilities, which may be identified within the County
or local mitigation strategies.
• Mitigation-related goals or objectives considered in the review and update of the overall Goals and
Objectives in Section 6 (Mitigation Strategy).
• Proposed, in-progress, or potential mitigation projects, actions, and initiatives to be incorporated into
the updated County and local mitigation strategies.
The following local regulations, codes, ordinances, and plans were reviewed during this process to develop
mitigation planning goals, objectives, and strategies that are consistent across local and regional planning and
regulatory mechanisms to accomplish complementary and mutually supportive strategies:
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• Master/Comprehensive Plans
• Building Codes
• Zoning and Subdivision Ordinances
• NFIP Flood Damage Prevention Ordinances
• Site Plan Requirements
• Stormwater Management Plans
• Emergency Management and Response Plans
• Land Use and Open Space Plans
• Capital Plans
• Texas State Hazard Mitigation Plan (2018)
2.6 INTEGRATION WITH EXISTING PLANNING MECHANISMS AND
PROGRAMS
Effective mitigation is achieved when hazard awareness and risk management approaches and strategies become
an integral part of public activities and decision-making. Within the Galveston County, there are many existing
plans and programs that support hazard risk management, and thus it is critical that this hazard mitigation plan
integrate, coordinate with, and complement, those existing plans, and programs.
The Capability Assessment section of Section 5 (Capability Assessment) provides a summary and description
of the existing plans, programs, and regulatory mechanisms at all levels of government (federal, state, county,
and local) that support hazard mitigation within the County. Within each jurisdictional annex in Section 9, the
County and each participating jurisdiction identified how they integrated hazard risk management into their
existing planning, regulatory, and operational/administrative framework (integration capabilities) and how they
intend to promote this integration (integration actions).
A further summary of these continued efforts to develop and promote a comprehensive and holistic approach to
hazard risk management and mitigation is presented in Section 7 (Plan Maintenance).
2.7 CONTINUED PUBLIC INVOLVEMENT
Galveston County and participating jurisdictions are committed to the continued involvement of the public in
the hazard mitigation process. This HMP update will be posted online at https://gcoem.org/galveston-county-
multi-jurisdiction-hazard-mitigation-plan/. Each jurisdiction’s elected official shall be responsible for receiving,
tracking, and filing public comments regarding this HMP update.
A notice regarding annual updates of the plan and the location of plan copies will be publicized annually after
the Steering Committee’s annual evaluation and posted on the public website at https://gcoem.org/galveston-
county-multi-jurisdiction-hazard-mitigation-plan/
The public will have an opportunity to comment on the plan as a part of the annual mitigation planning evaluation
process and the next five-year mitigation plan update. The HMP Coordinator is responsible for coordinating the
plan evaluation portion of the meeting, soliciting feedback, collecting, and reviewing the comments, and
ensuring their incorporation in the five-year plan update as appropriate. The purpose of these meetings would be
to provide the public an opportunity to express concerns, opinions, and ideas about the plan.
Further details regarding continued public involvement are provided in Section 7 (Plan Maintenance).
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After completion of this plan, implementation and ongoing maintenance will continue to be a function of the
Steering Committee. The Steering Committee will review the plan and accept public comment as part of an
annual review and as part of five-year mitigation plan updates.
A notice regarding annual updates of the plan and the location of plan copies will be publicized annually after
the Steering Committee’s annual evaluation and posted on the public web site.
Laura Norman, Galveston Count’s Deputy Emergency Management Coordinator, is identified as the Galveston
County’s HMP Coordinator in Section 7 (Plan Maintenance), and is responsible for receiving, tracking, and
filing public comments regarding this plan. Contact information is: laura.norman@co.galveston.tx.us
SECTION 3: GALVESTON COUNTY PROFILE
Galveston County, TX | Hazard Mitigation Plan 3-1
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SECTION 3. GALVESTON COUNTY PROFILE
3.1 GENERAL INFORMATION
Prior to European settlement, indigenous peoples inhabited the mainland and island area now known as
Galveston County. The first Europeans to lay claim to the area were Spanish and named the area after Viceroy
Bernardo de Gálvez. In the early 1800’s, Americans began arriving in the area, but the County was not formally
established until 1839. When Texas joined the Union, Galveston was the largest city in Texas (Kleiner 2021).
The county commissioners court serves as the governing body in the county. This administrative body was
established by the Texas Constitution of 1876 and is comprised of a county judge and four elected
commissioners. The major duties of the commissioner’s court involve overseeing county functions in their area.
Galveston County is comprised of the cities of: Bayou Vista, Clear Lake Shores, Dickinson, Friendswood,
Galveston, Hitchcock, Jamaica Beach, Kemah, La Marque, League City, Santa Fe, Texas City, and the Village
of Tiki Island. The City of Galveston is the county seat. The jurisdictions participating in this plan update include
all of the unincorporated areas of the County and the incorporated jurisdictions of:
• Bayou Vista
• Clear Lake Shores
• Dickinson
• Friendswood
• Hitchcock
• Jamaica Beach
• Kemah
• La Marque
• League City
• Santa Fe
• Tiki Island
3.2 MAJOR PAST HAZARD EVENTS
Presidential disaster declarations are issued for hazard events that cause more damage than state and local
governments can handle without assistance from the federal government. No specific dollar loss threshold has
been established for these declarations. A presidential disaster declaration puts operationalizes federal recovery
programs to assist disaster victims, businesses, and public entities. Programs can be matched by state programs.
Review of presidential disaster declarations helps establish the probability of reoccurrence for each hazard and
identify targets for risk reduction. Table 3-1 shows FEMA disaster declarations that have included Galveston
County between 2001 and February 2021.
Table 3-1. History of Hazard Events in Galveston County, Texas
Disaster
Number Declaration Date Event Date Incident Type Title
DR-1379 June 9, 2001 June 5-20, 2001 Coastal Storm Tx-Tropical Storm Allison-06-06-
2001
DR-1434 September 26, 2002 September 6-30, 2002 Coastal Storm Tropical Storm Fay
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Disaster
Number Declaration Date Event Date Incident Type Title
DR-1479 July 17, 2003 July 15-28, 2003 Hurricane Hurricane Claudette
EM-3216 September 2, 2005 August 29-October 1, 2005 Hurricane Hurricane Katrina Evacuation
EM-3261 September 21, 2005 September 20-October 14,
2005 Hurricane Hurricane Rita
DR-1606 September 24, 2005 September 23-October 14,
2005 Hurricane Hurricane Rita
DR-1624 January 11, 2006 November 27, 2005-May 14,
2006 Fire Extreme Wildfire Threat
EM-3277 August 18, 2007 August 17-September 5, 2007 Hurricane Hurricane Dean
EM-3284 March 14, 2008 March 14-September 1, 2008 Fire Wildfires
EM-3290 August 29, 2008 August 27-September 7, 2008 Hurricane Hurricane Gustav
DR-1791 September 13, 2008 September 7-October 2, 2008 Hurricane Hurricane Ike
EM-3294 September 10, 2008 September 7-26, 2008 Hurricane Hurricane Ike
DR-4245 November 25, 2015 October 22-31, 2015 Severe
Storm(s)
Severe Storms, Tornadoes, Straight-
line Winds, and Flooding
DR-4332 August 25, 2017 August 23-September 15,
2017 Hurricane Hurricane Harvey
EM-3458 March 13, 2020 January 20, 2020 Biological COVID-19
DR-4485 March 25, 2020 January 20, 2020 Biological COVID-19 Pandemic
EM-3530 July 26, 2020 July 25-31, 2020 Hurricane Hurricane Hanna
EM-3540 August 24, 2020 August 23-27, 2020 Hurricane Tropical Storms Marco and Laura
DR-4572 December 9, 2020 August 23-27, 2020 Hurricane Hurricane Laura
EM-3554 February 19, 2021 February 11-21, 2021 Severe
Storm(s) Severe Winter Storm
DR 4586 February 19, 2021 February 11-21, 2021 Severe
Storm(s) Severe Winter Storm
3.3 PHYSICAL SETTING
This section presents the physical setting of the County, including land use/land cover, location, climate,
hydrography and hydrology, topography, and geology.
3.3.1 Location
Galveston County is located on the Gulf Coast of Texas, east of Brazoria County, west of Chambers County and
south of Harris County. According to the U. S. Census Bureau, Galveston County has 378 square miles of land
area, 495 square miles of water area, and is the 244th largest county in Texas by total area.
3.3.2 Topography and Geology
Galveston County is part of the Coastal Prairie physiographic province, underlaid by Deltaic sands and muds in
a nearly flat stratum. The topography consists of a nearly flat prairie. Galveston County is located in the Gulf
Coast Prairie and Marshes ecoregion of Texas, which is characterized by expansive rolling brushlands and
prairies that transition to estuarine marshes and dune environments. The County is a small part of this ecosystem,
which stretches from Louisiana to Mexico. The Gulf coastline is characterized by marshy plains, narrow beach
ridges, and long barrier islands that separate the mainland coast from the Gulf waters. On the coast, Galveston
Island has an elevation of approximately 7 feet, while inland Friendswood is approximately 31 feet.
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3.3.3 Hydrography and Hydrology
Galveston County is bordered to the north by Clear Creek, a small river, which forms the boundary with Harris
County and empties into Clear Lake, which in turn feeds Galveston Bay. Galveston Bay is the seventh largest
estuary in the United States and is connected to the Gulf of Mexico. Two major bayou watersheds are also located
in the County.
Dickinson Bayou Watershed
The Dickinson Bayou watershed encompasses approximately 100 square miles of land that drains water into the
bayou. In Galveston County, it encompasses the cities of Dickinson, Friendswood, Kemah, League City, Santa
Fe, and Texas City. The Dickinson Bayou Watershed Partnership developed a Bacteria Implementation Plan to
reduce the bacteria concentrations in the watershed. The plan addresses on-site sewage facilities (septic systems),
wastewater treatment facilities and collection systems, animal waste, restoration and repair of riparian zones,
and preservation and restoration of the natural wetlands (Dickinson Bayou Watershed Partnership n.d.).
Highland Bayou Coastal Basin
The Highland Bayou Coastal Basin is a 120 square mile drainage basin located on mainland Galveston County.
Bayou and stream segments consist of non-tidal, tidally influenced, and tidal waters. Fresh water in the bayous
is largely precipitation-driven overland flows. Fresh water in the bayous is largely precipitation-driven overland
flows. The freshwater bayous transition to estuarine conditions. (Texas A&M AgriLife Extension n.d.).
3.3.4 Climate
Galveston County’s temperatures range from an average low of 48.9 degrees in January to an average high of
79.8 degrees in August. The County receives approximately 47 inches of rainfall each year (NWS 2020). The
County receives moderating climatic influences due to its proximity to the Gulf of Mexico.
3.3.5 Land Use and Land Cover
The prevailing land use types in Galveston County are urban and wetland, which comprise 37.6 percent 26.9
percent, respectively, of the County. Agricultural lands (14.9 percent) and forests (10.3 percent) are smaller land
uses, while barren land and water are the minority uses. Table 3-2 summarizes the land use for Galveston County.
Figure 3-1 shows the distribution of land use throughout the County.
Table 3-2. Land Use Breakdown for Galveston County
Land Use Category
2011 Data 2016 Data 2019 Data
Acreage
Percent of
County Acreage
Percent of
County Acreage
Percent of
County
Agriculture 36,498 14.0% 36,711 14.1% 38,816 14.9%
Barren 9,468 3.6% 4,694 1.8% 4,569 1.8%
Forest 31,289 12.0% 30,875 11.9% 26,798 10.3%
Urban 91,639 35.2% 93,316 35.9% 97,795 37.6%
Water 16,072 6.2% 22,459 8.6% 22,207 8.5%
Wetland 75,136 28.9% 72,055 27.7% 69,928 26.9%
Galveston County (Total) 260,102 100.0% 260,111 100.0% 260,113 100.0%
Sources: NLCD 2014, NLCD 2019, NLCD 2021
Note: Changes in total LULC indicates areas where unclassified LULC are now classified
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Figure 3-1. 2021 Land Use in Galveston County, Texas
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3.4 POPULATION AND DEMOGRAPHICS
According to the 2020 Decennial Census, Galveston County had a population of 350,682 people which
represents a significant increase from the 2010 U.S. Census population of 291,309 people. HAZUS demographic
data will be used in the loss estimation analyses in Section 4 of this plan. All demographic data in HAZUS
corresponds to the 2010 U.S. Census data. Table 3-3 presents the population statistics for Galveston County
based on the 2000, 2010, and 2020 U.S. Census data. For the purposes of this plan, the 2020 Census was used
where the data was available and supplemented with HAZUS data (representing 2010 data).
Table 3-3. Recent Population by Jurisdiction
Population
Jurisdiction 1990 2000 2010 2020
Bayou Vista 1,320 1,644 1,537 1,631
Clear Lake Shores 1,135 1,205 1,063 1,249
Friendswood 22,809 29,214 35,805 41,213
Hitchcock 5,868 6,386 6,961 7,301
Jamaica Beach 624 1,075 983 1,081
Kemah 1,150 2,330 1,773 2,037
La Marque 14,120 13,682 14,509 18,347
League City 29,903 45,444 83,560 114,392
Santa Fe 8,628 9,548 12,222 13,599
Tiki Island 537 1,016 968 1,065
Unincorporated 131,302 138,614 131,928 148,767
Total 217,396 250,158 291,309 350,682
Source: 2017 Galveston County HMP, U. S. Census
Population and Demographic Trends
This section discusses population trends to use as a basis for estimating future changes that could result from the
seasonal character of the population and significantly change the character of the area. Population trends can
provide a basis for making decisions on the type of mitigation approaches to consider and the locations in which
these approaches should be applied. This information can also be used to support planning decisions regarding
future development in vulnerable areas.
According to the U.S. Census Bureau, the 2010 population for Galveston County was 291,309 persons, which
is a 16.5% increase from the 2000 Census population of 250,158. Over the last 50 years, from 1970 to 2020, the
County has seen notable population growth. The largest increase in absolute terms and in percentage was
between 2010 and 2020.
Table 3-4. Galveston County Population Trends, 1960 to 2020
Year Population Change in Population Percent (%) Population
Change
1970 169,812 - -
1980 195,738 25,926 15.2%
1990 217,396 21,658 11.1%
2000 250,158 32,762 15.1%
2010 291,309 41,151 16.5%
2020 350,682 59,373 20.4%
Source: 2017 Galveston County HMP, U. S. Census
Note: Change in population and percent in population change were calculated from available data.
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The Texas Demographic Center has produced population estimates for the region that were last updated in 2018
based on 2010 Census data. The estimates show projected growth between 7.54 and 9.36 percent every five years
from 2025 to 2050.
Figure 3-2. Galveston County Population Projected Change, 2025 to 2050
Source: (Texas Demographic Center Population Projections 2018)
3.4.1 Vulnerable Populations
DMA 2000 requires that HMPs consider socially vulnerable populations. These populations can be more
susceptible to hazard events, based on a number of factors including their physical and financial ability to react
or respond during a hazard and the location and construction quality of their housing. For the purposes of this
study, vulnerable populations shall include (1) the elderly (persons aged 65 and over) and (2) those living in
low-income households.
Table 3-5. Galveston Vulnerable Population Statistics
Municipality
ACS 2019
Total Population 65+
% Population
65+
Low-Income
Population
% Low-Income
Population of
Total
Galveston County 342,139 51,182 15% 36,764 10.9%
Source: 2019 American Community Survey 1-Year Estimates (2021)
* Individuals below poverty level (Census poverty threshold for a 3-person family unit is approximately $18,500)
It is noted that the Census data for household income provided in HAZUS includes two ranges ($0-10,000 and
$10,000-$20,000/year) that were totaled to provide the “low-income” data used in this study. This does not
correspond exactly with the “poverty” thresholds established by the 2019 U.S. Census Bureau, which identifies
households with three adults and no children with an annual household income below $19,998 per year, or
households with two adults and one child with an annual household income below $17,622 per year as “low
income” for this region. This difference is not believed to be significant for the purposes of this planning effort.
0%
1%
2%
3%
4%
5%
6%
7%
8%
9%
10%
2025 - 2030 2030 - 2035 2035 - 2040 2040 - 2045 2045 - 2050% 10-Year Change in PopulationGalveston County
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The 2019 American Community Survey data identified approximately 36,764 people in Galveston County living
below the poverty line. This represents nearly 11 percent of the population. Though this is an absolute increase
from 36,063 in 2010, the proportion of individuals in poverty has declined by 1.6% since 2010.
Income
The 2019 American Community Survey 5-Year Estimates provides that the median household income in
Galveston County was $74,977. The U.S. Census Bureau identifies households with two adults and one child
with an annual household income below $17,622 per year as low income (U. S. Census 2021). The 2019
American Community Survey 5-Year Estimates indicates that nearly 11 percent of persons are below the poverty
level within the County.
The spatial U.S. Census data for household income provided in HAZUS includes two ranges (less than $10,000
and $10,000-$20,000/year) that were totaled to provide the low-income data used in this study. This does not
correspond exactly with the poverty thresholds established by the 2019 U.S. Census Bureau data. This difference
is not believed to be significant for the purposes of this planning effort; therefore, for the exposure and loss
estimations in the risk assessment, the 2010 U.S. Census data in HAZUS is reported.
Physically or Mentally Disabled
According to the Centers for Disease Control, “A disability is any condition of the body or mind (impairment)
that makes it more difficult for the person with the condition to do certain activities (activity limitation) and
interact with the world around them (participation restrictions) (CDC 2020).” Cognitive impairments can
increase the level of difficulty that individuals might face during an emergency and reduce an individual’s
capacity to receive, process, and respond to emergency information or warnings. Individuals with a physical or
sensory disability can face issues of mobility, sight, hearing, or reliance on specialized medical equipment.
According to the 2019 American Community Survey, 11.1 percent of residents in Galveston County are living
with a disability.
Non-English Speakers
Individuals who are not fluent or working proficiency in English are vulnerable because they can have difficulty
with understanding information being conveyed to them. Cultural differences also can add complexity to how
information is being conveyed to populations with limited proficiency of English (CDC 2021). According to the
2019 American Community Survey, 22% of the County’s population over the age of 5 primarily speaks a
language other than English at home. Approximately, 6.6% of the population over the age of 5 speaks limited
English.
3.4.2 General Building Stock
For this Plan, the default general building stock in Hazus was updated and replaced with a custom building
inventory for Galveston both at the aggregate and structure level. The building stock update was performed
using 2021 certified assessor data from the Galveston Central Appraisal District (GCAD). The replacement cost
value was calculated using the square footage value of each building and RS Means 2021 data.
For the purposes of this plan, there are approximately 209,947 structures identified through data provided by the
GCAD. These structures account for a replacement cost value of approximately $166.3 billion (structure and
contents). Estimated content value was calculated by using 50-percent of the residential replacement cost value,
and 100-percent of the non-residential replacement values. Using this methodology, there is approximately
$70.1 billion in contents within these structures. Table 3-6 presents building and improvement values in the
County.
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Table 3-6. Number of Buildings and Improvement Value in Galveston County
Jurisdiction
All Occupancies
Count
Replacement Cost
Value (Structure
Only)
Replacement Cost Value
(Contents Only)
Total Replacement
Cost Value
(Structure + Contents)
Clear Lake Shores (C) 1,155 $519,006,216.88 $385,556,151.78 $904,562,368.66
Dickinson (C) 10,351 $3,924,480,999.53 $2,677,229,646.10 $6,601,710,645.63
Friendswood (C) 14,891 $6,532,042,745.35 $4,283,413,638.77 $10,815,456,384.12
Hitchcock (C) 5,452 $2,606,611,538.31 $1,985,425,113.55 $4,592,036,651.86
Jamaica Beach (C) 1,291 $292,462,937.69 $165,742,901.13 $458,205,838.82
Kemah (C) 1,634 $1,410,211,778.23 $1,221,490,327.37 $2,631,702,105.60
La Marque (C) 10,749 $4,518,194,733.81 $3,409,097,788.47 $7,927,292,522.28
League City (C) 46,742 $18,876,791,173.65 $12,361,183,420.45 $31,237,974,594.10
Santa Fe (C) 7,942 $2,826,459,977.04 $2,005,168,185.08 $4,831,628,162.13
Bayou Vista (C) 1,365 $287,902,599.47 $157,451,487.86 $445,354,087.33
Tiki Island (V) 868 $240,413,556.57 $124,795,588.86 $365,209,145.44
Galveston County (Total) 209,947 $96,229,561,611.86 $70,092,043,076.59 $166,321,604,688.46
Sources: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Notes: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County. RCV =
Land Use and Population Trends
This Hazard Mitigation Plan provides a general overview of population, land use, and types of development
occurring within the study area. An understanding of these development trends can assist in planning for further
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place to
protect human health and community infrastructure.
3.4.3 Land Use Trends
While the County does not have a comprehensive plan to cite land use trends, patterns emerge from the statistics
in this plan. The amount of urban land has been increasing over the past decade, while the amount of barren
land, forest land, and wetland has decreased. While the amount of agricultural land has increase slightly, the
workforce in the County is predominantly in the retail and healthcare sectors. The aging population is also a
trend that may impact land use in the County.
Economy
The U.S. Census Bureau’s Economic Census provides an annual series of sub-national economic data by industry
covering the majority of the country’s economic activity. According to the 2019 Galveston County Economic
Census, the retail sector has the largest number of employees, while the accommodation and food services sector
has the largest number of employees. The healthcare and social assistance industry comprises the highest payroll
(nearly $628 million) and the second-highest number of jobs.
Table 3-7. 2017 Economic Census for Galveston County, Texas
Sector
# of
Establishments # of employees
Annual payroll
($1,000)
Utilities 11 300 29,067
Manufacturing 162 5,481 558,130
Wholesale trade 218 1,952 107,130
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Sector
# of
Establishments # of employees
Annual payroll
($1,000)
Retail trade 944 14,163 384,500
Transportation and warehousing 156 3,132 144,796
Information 77 742 37,892
Finance and insurance 380 4,373 256,469
Real estate and rental and leasing 338 1,920 100,921
Professional, scientific, and technical services 575 4,388 241,018
Professional, scientific, and technical services (establishments
subject to federal income tax)
D 2,500 to 4,999
employees
D
Administrative and support and waste management and
remediation services
282 3,752 126,944
Educational services 65 437 9,810
Educational services (establishments subject to federal income
tax)
D 250 to 499
employees
D
Educational services (establishments exempt from federal
income tax)
D 20 to 99
employees
D
Health care and social assistance 648 15,736 627,900
Health care and social assistance (establishments subject to
federal income tax)
572 7,751 267,078
Health care and social assistance (establishments exempt from
federal income tax)
76 7,985 360,822
Arts, entertainment, and recreation 106 1,959 36,192
Arts, entertainment, and recreation (establishments subject to
federal income tax)
85 1,734 32,377
Arts, entertainment, and recreation (establishments exempt
from federal income tax)
21 225 3,815
Accommodation and food services 757 17,232 299,222
Other services (except public administration) 463 2,828 94,886
Other services (except public administration) (establishments
subject to federal income tax)
373 2,343 77,868
Other services (except public administration) (establishments
exempt from federal income tax)
90 485 17,018
Total (does not include withheld data or range of numbers) 6,399 98,918 $3,813,855
Source: U.S. Census, Economic Census 2017
D = Withheld to avoid disclosing data for individual companies; data are included in higher level totals.
Agriculture
Farmland plays a smaller role in Galveston County than in does in many other counties in Texas. The US
Department of Agriculture produces a Census of Agriculture that tracks agricultural data on the County level. In
Galveston County, the number of farms has increased by 3% since 2012 but the acreage of farms has decreased
18% during the same time to just over 73,000 acres of land for farming. Cattle, hogs, sheep, layers, and meat
chickens make up the main sales for farms in the County. Galveston County’s agriculture products generate
more than $9.2 million in sales each year, but farms operate at a net loss (USDA 2019).
Corridors and Gateways
Interstate 45, known as the Gulf Freeway, runs from Galveston Island north through the middle of the County.
It is an important corridor that ties Galveston County to the Houston metropolitan area. State Highway 3 runs
parallel to I-45 from La Marque through League City into Harris County. State Highway 6 branches off of I-45
at Bayou Vista and continues northwest through Brazoria and Harris Counties. State Highway 87 runs along
Bolivar Peninsula and Galveston Island where it empties into I-45. State Highway 146 starts at the intersection
of State Highway 6 and I-45 where it heads north along the bay side of Galveston County into Harris County.
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3.4.4 Population Trends
Galveston County has grown significantly in recent years. Between 2010 and 2020 alone, the estimated
population has increased from 291,309 residents to 350,682 residents, a 20 percent increase. The County has
grown steadily since 1970, adding between 11 and 16 percent to its population every decade until 2010. The
County’s median age increased from 32.5 years in 1990 to 38.7 years in 2020.
As the County has grown, it has also aged and change composition. In 1990, those between the ages of 25 and
44 years old represented the plurality of residents. As of 2010, those between the ages of 45 and 64 years of age
represent the plurality. Whereas the population share of those under 18 years has remained relatively constant,
the share of residents between the ages of 45 and 64 years has increased from 19.4 percent to 28.1 percent during
the same time. The County has also diversified racially and ethnically, with the share of Black residents
increasing by 5.1 percent and the share of Asian residents more than doubling (3,569 to 8,690) from 1990 to
2010.
3.4.5 Future Growth and Development
While Galveston County does not have a Comprehensive Plan that addresses the County as a whole, several
communities look at future growth and development in their city plans. By considering these city plans, future
growth and development patterns throughout the planning area can be generalized.
• City of Dickinson – Based on the Future Land Use Plan, the City of Dickinson would add 8,941
residential dwellings, or 26,824 residents and 65,259 new jobs within the city limits and 1,839
residential dwelling units or 5,518 residents and 6,013 new jobs in the extraterritorial jurisdiction (ETJ).
• City of Friendswood – Full buildout is projected with a population of 45,000 to 50,000.
• City of Hitchcock – Agricultural residential land is expected to decrease 10 percent while single family
residential, multi-family residential, and manufactured homes are expected to increase slightly. Open
space is expected to increase with a designated 3,300-acre wetland conservation area.
• City of League City – The Future Land Use Plan accounts for a population of up to 178,875 while
increasing employment opportunities. New residential activity primarily focuses on rural/estate and
suburban character development with a limited number of mixed-use centers.
3.5 LIFELINES AND CRITICAL FACILITIES
Critical infrastructure and facilities are those that are
essential to the health and welfare of the population.
These facilities are especially important after any
hazard event. Critical facilities are those that maintain
essential and emergency functions and are typically
defined to include police and fire stations, schools, and
emergency operations centers. Critical infrastructure
can include the roads and bridges that provide ingress
and egress and allow emergency vehicles access to
those in need and the utilities that provide water,
electricity, and communication services to the
community. Also included are Tier II facilities
(hazardous materials) and rail yards; rail lines hold or
carry significant amounts of hazardous materials with
Critical Facilities are those facilities considered critical to
the health and welfare of the population and that are
especially important following a hazard. As defined for
this HMP, critical facilities include transportation systems,
lifeline utility systems, high-potential loss facilities, and
hazardous material facilities, and essential facilities
Essential facilities are a subset of critical facilities that
include those facilities that are important to ensure a full
recovery following the occurrence of a hazard event. For
the county risk assessment, this category was defined to
include police, fire, EMS, schools/colleges, shelters, senior
facilities, and medical facilities.
Lifelines enable the continuous operation of critical
business and government functions and are essential to
human health and safety or economic security.
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a potential to impact public health and welfare in a hazard event.
Beginning in 2017, FEMA developed a new construct to increase effectiveness for disaster operations and
position response to catastrophic incidents. This construct, known as “community lifelines”, represents the most
fundamental services in the community that, when stabilized, enable all other aspects of society. Following a
disaster event, intervention is required to stabilize community lifelines. Lifelines are divided into seven
categories which include:
▪ Safety and Security
▪ Food, Water, Shelter
▪ Health and Medical
▪ Energy (Power and Fuel)
▪ Communications
▪ Transportation
▪ Hazardous Materials
To facilitate consistency with the National Response Framework, FEMA Strategic Plan, and guidance for the
Building Resilient Infrastructure and Communities grant program, crit ical facilities in Galveston County are
discussed in terms of lifelines.
A comprehensive inventory of critical facilities and lifelines in Galveston County was developed from various
sources including input from the Planning Committees. The inventory of critical facilities presented in this
section represents the current state of this effort at the time of publication of the HMP and was used for the risk
assessment in Section 4 (Risk Assessment).
3.5.1 Safety and Security
This section provides information on Safety and Security lifelines. Components of this lifeline category include
law enforcement/security, fire services, search and rescue services, government services, and community safety
(e.g., dams). There are 405 safety and security lifelines in Galveston County.
Emergency Facilities
There are 31 police stations, 69 fire stations, and nine emergency operations centers (EOCs) in Galveston
County.
Schools
The County contains 142 primary education facilities, 12 secondary education facilities, and 13 colleges.
Government Buildings
There are 136 government buildings located in Galveston County and includes municipal buildings, public works
departments, libraries, and prisons.
Dams and Levees
Galveston County contains one major dam and one 17-mile levee.
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Figure 3-3. Safety and Security Lifelines in Galveston County
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3.5.2 Food, Water, and Shelter Lifelines
Food, Water, and Shelter lifelines include facilities pertaining to food supply (distribution facilities, programs,
and supply chain), water supply (including both potable and wastewater systems), shelter (housing and hotels),
and agricultural facilities.
Food Supply
Food supply includes commercial food distribution, commercial food supply chains, and food distribution
programs. Numerous grocery stores, including large chain stores, and one County-operated food bank are
located in Galveston County. In addition to the County’s food bank, there are numerous locations throughout
the County that provide food and meals to residents in need.
Water Supply
Potable Water
There are four potable water systems, 25 potable water wells, and 14 storage tanks in Galveston County. Water
is provided through surface water and groundwater systems located throughout the County. Numerous utility
districts and improvement districts distribute potable water to residents throughout.
Wastewater Facilities
The County contains 82 lift stations, 30 pump stations, and 2 treatment plants. Similar to potable water, there
are numerous utility districts that provide wastewater treatment and services to the County.
Shelters
Three buildings are identified as shelters in Galveston County and hundreds of hotels are located throughout the
County.
3.5.3 Health and Medical Lifelines
Health and medical lifelines include medical care (e.g., hospitals, pharmacies, long-term care facilities), patient
movement (e.g., EMS), fatality management, public health, and medical supply chain. In Galveston County,
there are 91 facilities identified as health and medical lifelines. This includes 27 hospitals, 18 medical clinics,
40 nursing homes, 6 urgent care centers, and 8 ambulance service providers.
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Figure 3-4. Food, Water, and Shelter Lifelines in Galveston County
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Figure 3-5. Health and Medical Lifelines in Galveston County
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3.5.4 Energy (Power and Fuel) Lifelines
The energy (power and fuel) lifeline include facilities pertaining to the power grid and fuel supplies. Galveston
County has 598 energy lifelines: one gas pipeline, 535 gas wells, two petroleum ports, 7 power plans, three pump
stations, and 50 substations. Figure 3-6 shows the distribution of energy lifelines throughout Galveston County.
3.5.5 Communication Lifelines
Communication lifelines include facilities pertaining to infrastructure, alerts/warnings/messages, 911 and
dispatch, responder communications, and finance. There are 111 communication facilities in Galveston County:
73 banks and 38 communication towers. Refer Figure 3-7 to see locations of communication lifelines in the
County.
3.5.6 Transportation Lifelines
Transportation lifelines include facilities pertaining to highway/roadway, mass transit, railway, aviation, and
maritime. Major highways in the County include Interstate 45 and State Highways 3, 6, 87, and 146. Figure
3-8 shows the distribution of transportation lifelines throughout the County.
Bridges
There are 491 bridges and 35 railroad bridges in Galveston County.
Ports
There are 355 port facilities in Galveston County.
Public Transportation
There are multiple public transportation providers in Galveston County including a fixed-route bus service, ADA
paratransit service, taxi services, and a ferry.
Rail
The Galveston Railroad operates 32 miles of track.
Air
Galveston County has one international airport, two airstrips, and two heliports.
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Figure 3-6. Energy Lifelines in Galveston County
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Figure 3-7. Communication Lifelines in Galveston County
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Figure 3-8. Transportation Lifelines in Galveston County
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3.5.7 Hazardous Materials Lifelines
The hazardous material lifeline includes facilities pertaining to facilities containing hazardous materials and
HAZMAT/pollutants/containments. There are 68 hazardous material lifelines in Galveston County: 8 Superfund
sites and 60 waste stations.
HAZMAT Facilities
A Superfund site consists of land in the United States that has been contaminated by hazardous waste and
identified by the U.S. Environmental Protection Agency (EPA) as a candidate for cleanup because it poses a risk
to human health or the environment. These sites are placed on the National Priorities List (NPL), the list of
national priorities among the known releases or threatened releases of hazardous substances, pollutants, or
contaminants throughout the United States and its territories. The NPL is intended primarily to guide EPA in
determining which sites warrant further investigation.
Abandoned hazardous waste sites placed on the federal NPL include those that EPA has determined present a
significant risk to human health or the environment, with the sites being eligible for remediation under the
Superfund Trust Fund Program. As of 2021, Galveston County hosts 8 hazardous sites in the federal Superfund
Program that are listed as on the NPL (CERCLIS 2021).
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Figure 3-9 Hazardous Materials Lifelines in Galveston County
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SECTION 4. RISK ASSESSMENT
Risk assessment is the process of measuring the potential loss of life, personal injury, economic injury, and
property damage resulting from identified hazards. It allows emergency management personnel to establish early
response priorities by identifying potential hazards and vulnerable assets. The process focuses on the following
elements:
• Hazard identification—Use all available information to determine what types of hazards may affect a
jurisdiction, how often they can occur, and their potential severity.
• Exposure identification—Estimate the total number of people and properties in the jurisdiction that are
likely to experience a hazard event if it occurs.
• Vulnerability identification and loss estimation—Assess the impact of hazard events on the people,
property, environment, economy, and lands of the region, including estimates of the cost of potential
damage or cost that can be avoided by mitigation.
The risk assessment for this hazard mitigation plan update evaluates the risk of natural hazards prevalent in the
planning area and meets requirements of the Disaster Mitigation Act (44 CFR, Section 201.6(c)(2)).
To protect individual privacy and the security of critical facilities, information on properties assessed is presented
in aggregate, without details about specific individual personal or public properties.
4.1 METHODOLOGY AND TOOLS
The following describes the methodology and tools used to conduct the risk assessment for the Galveston County
HMP 2022 update.
4.1.1 Risk Assessment Tools
Mapping
National, state, and county databases were reviewed to locate available spatially based data relevant to this
planning effort. Maps were produced using geographic information system (GIS) software to show the spatial
extent and location of hazards when such datasets were available. These maps are included in the hazard profile
chapters of this document.
Hazus
In 1997, FEMA developed the standardized Hazards U.S. (Hazus) model to estimate losses caused by
earthquakes and identify areas that face the highest risk and potential for loss. Hazus was later expanded into a
multi-hazard methodology with new models for estimating potential losses from hurricanes and floods.
Hazus is a GIS-based software program used to support risk assessments, mitigation planning, and emergency
planning and response. It provides a wide range of inventory data, such as demographics, building stock, critical
facility, transportation and utility lifeline, and multiple models to estimate potential losses from natural disasters.
The program maps and displays hazard data and the results of damage and economic loss estimates for buildings
and infrastructure. Its advantages include the following:
• Provides a consistent methodology for assessing risk across geographic and political entities.
• Provides a way to save data so that they can readily be updated as population, inventory, and other
factors change and as mitigation planning efforts evolve.
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• Facilitates review of mitigation plans because it helps to ensure that FEMA methodologies are
incorporated.
• Supports grant applications by calculating benefits using FEMA definitions and terminology.
• Produces hazard data and loss estimates that can be used in communication with local stakeholders.
• Is administered by the local government and can be used to manage and update a hazard mitigation plan
throughout its implementation.
Level of Detail for Evaluation
Hazus provides default data for inventory, vulnerability, and hazards; these default data can be supplemented
with local data to provide a more refined analysis. The model can carry out three levels of analysis, depending
on the format and level of detail of information about the planning area:
• Level 1—All of the information needed to produce an estimate of losses is included in the software’s
default data. These data are derived from national databases and describe in general terms the
characteristic parameters of the planning area.
• Level 2—More accurate estimates of losses require more detailed information about the planning area.
To produce Level 2 estimates of losses, detailed information is required about local geology, hydrology,
hydraulics, and building inventory, as well as data about utilities and critical facilities. This information
is needed in a GIS format.
• Level 3—This level of analysis generates the most accurate estimate of losses. It requires detailed
engineering and geotechnical information to customize it for the planning area.
4.1.2 Risk Assessment Approach
The risk assessments in this plan describe the risks associated with each hazard of concern identified. The
following steps were used to define the risk of each hazard:
• Identify and profile each hazard—The following information is given for each hazard:
o Geographic areas most affected by the hazard
o Event frequency estimates
o Severity estimates
o Warning time likely to be available for response.
• Determine exposure to each hazard—Exposure was assessed by overlaying hazard maps with an
inventory of structures, facilities, and systems to decide which of them would be exposed to each hazard.
• Assess the vulnerability of exposed facilities—Vulnerability of exposed structures and infrastructure
was evaluated by interpreting the probability of occurrence of each event and assessing structures,
facilities, and systems that are exposed to each hazard. Tools such as GIS and FEMA’s hazard-modeling
program Hazus were used for this assessment for the earthquake, flood, and hurricane hazards. Outputs
similar to those from Hazus were generated for other hazards, using data generated through GIS.
Flood and Hurricane
The following hazards were evaluated using Hazus.
Flood
The 1-percent and 0.2-percent chance flood events were examined to evaluate Galveston County’s risk and
vulnerability to the flood hazard.
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The effective Galveston County FEMA Digital Flood Insurance Rate Map (DFIRM) dated February 16, 2018
was used to evaluate potential future losses caused by the 1-percent and 0.2-percent annual chance flood events.
These flood events are generally those considered by planners and evaluated under federal programs such as the
NFIP.
The coastal flood risk areas for the 1-percent and 0.2-percent annual chance flood events were published on the
FEMA map service center December 2014. The 2014 coastal flood risk area was used to divide the AE zones in
the 2019 effective DFIRMs into coastal and riverine AE zones. The coastal AE zones were merged with 2019
VE zones to create the coastal flood hazard boundary, which was used to create the coastal depth grids for the
1-percent and 0.2-percent annual chance flood events. The riverine AE zones were merged with the AO and A
zones to create the 1-percent annual chance flood event riverine depth grid. The 0.2-percent annual chance flood
event riverine depth grid was created by merging the riverine AE, A, and AO zones with the 0.2-percent annual
chance X zones. The final coastal and riverine depth grids were processed using a 2018 USGS 1-meter resolution
Digital Elevation Model (DEM). These depth grids were integrated into the Hazus v5.0 riverine and coastal flood
models used to estimate potential losses for the 1-percent and 0.2-percent annual chance flood events.
A Level 2 Hazus riverine and coastal flood analysis was performed. Both the critical facility and building
inventories were formatted to be compatible with Hazus and its Comprehensive Data Management System
(CDMS). Once updated with the inventories, the Hazus riverine and coastal flood model was run to estimate
potential losses in Galveston County for the 1-percent and 0.2-percent annual chance flood events. A user-
defined analysis was also performed for the building stock. Buildings located within the floodplain were
imported as user-defined facilities to estimate potential losses to the building stock at the structural level. Hazus
calculated the estimated potential losses to the population (default 2010 U.S. Census data), potential damages to
the general building stock, and potential damages to critical facility inventories based on the depth grids
generated and the default Hazus damage functions in the flood model. Furthermore, social impacts and debris
were estimated by Hazus at the census block level. These results were presented at the municipal level. Since
there are multiple census blocks that contain more than one jurisdiction, a density analysis was used to extract
the percent of building structures that fall within each block and jurisdiction. The percentage was multiplied
against the results calculated for each block and summed for each municipality.
Hurricane
A Hazus probabilistic analysis was performed to analyze the wind hazard losses for Galveston County for the
100- and 500-year mean return period events. The probabilistic Hazus hurricane model activates a database of
thousands of potential storms that have tracks and intensities reflecting the full spectrum of Atlantic hurricanes
observed since 1886 and identifies those with tracks associated with the County. Hazus contains data on historic
hurricane events and wind speeds. It also includes surface roughness and vegetation (tree coverage) maps for
the area. Surface roughness and vegetation data support the modeling of wind force across various types of land
surfaces. Default demographic and updated building and critical facility inventories in Hazus were used for the
analysis. Although damages are estimated at the census tract level, results were presented at the municipal level.
Since there are multiple census tracts that contain more than one jurisdiction, a density analysis was used to
extract the percent of building structures that fall within each tract and jurisdiction. The percentage was
multiplied against the results calculated for each tract and summed for each municipality.
Coastal and Inland Erosion
Best available data was used to assess Galveston County’s vulnerability to coastal and inland erosion. To help
understand the geographic distribution of the County’s risk to coastal erosion, a 100-foot buffer was created
from NOAA’s 2011 shoreline. The inland erosion hazard area was determined using USDA’s Natural Resources
Conservation Service’s 2020 soil data for Galveston County. Soils with an erodibility factor (k) of 0.49 or greater
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were extracted to assess the County’s risk to inland erosion. Asset data (population, building stock, critical
facilities, and new development) were used to support an evaluation of assets exposed and potential impacts and
losses. To determine what assets are at risk to coastal and inland erosion, the County’s assets were overlaid with
the hazard area. Assets with their centroid located in the hazard area were totaled to estimate the number of
persons, buildings, and facilities at risk to impacts from coastal and inland erosion.
Expansive Soils
Best available data was used to assess Galveston County’s vulnerability to expansive soils. To help understand
the geographic distribution of expansive soils, USDA’s Natural Resources Conservation Service’s 2020 soil data
for Galveston County was referenced. Soils with linear extensibility greater than or equal to 6-percent were
selected as expansive soils. Asset data (population, building stock, critical facilities, and new development) were
used to support an evaluation of assets exposed and potential impacts and losses. To determine what assets are
at risk to impacts from expansive soils, the County’s assets were overlaid with the hazard area. Assets with their
centroid located in the hazard area were totaled to estimate the number of persons, buildings, and facilities at
risk to impacts from expansive soils.
Sea Level Rise: 1-foot Increments
Projected sea-level rise data (in one-foot increments) available from the NOAA Office of Coastal Management
(https://coast.noaa.gov/slrdata/) was considered and used for this analysis to understand the assets within
communities projected to be impacted by sea level rise (refer to Section 4.3.6 – Flood). Please note these levels
do not include additional storm surge due to a hurricane or Nor’easter. The current Flood Insurance Rate Maps
(FIRMs) also do not include the effects of sea-level rise. To assess the County’s risk to sea level rise, the 2017
NOAA 1-foot, 2-feet, 3-feet, and 4-feet sea level rise hazard areas were referenced.
Asset data (population, building stock, critical facilities and lifelines, and new development) were used to support
an evaluation of assets exposed and potential impacts and losses. To determine what assets are vulnerable to
sea-level rise, the County’s assets were overlaid with the hazard area. Assets with their centroid located in the
hazard area were totaled to estimate the number of persons, buildings, and facilities at risk to impacts from sea-
level rise.
Severe Winter Weather
All of Galveston County (population, buildings, and environment) is exposed and vulnerable to the winter storm
hazard. In general, structural impacts include damage to roofs and building frames, rather than building content.
Current modeling tools are not available to estimate specific losses for this hazard. A percentage of the custom-
building stock structural replacement cost value was utilized to estimate damages that could result from winter
storm conditions (i.e., 1-percent, 5-percent, and 10-percent of total replacement cost value). Given professional
knowledge and currently available information, the potential losses for this hazard are considered to be
overestimated; hence, providing a conservative estimate for losses associated with winter storm events.
Storm Surge: Categories 1-4
Storm surge hazard data available from the NOAA was considered and used for this analysis to understand the
assets within communities projected to be impacted by hurricane storm surge (refer to Section 4.3.8 –
Hurricane). This risk assessment used NOAA’s 2014 Sea Lake Overland Surge from Hurricanes (SLOSH) data
to analyze the assets at risk to impacts from hurricane storm surge. SLOSH represents potential flooding from
worst-case combinations of hurricane direction, forward speed, landfall point, and high astronomical tide were
used to estimate exposure. Please note these inundation zones do not include riverine flooding caused by
hurricane surge or inland freshwater flooding. The model, developed by the NOAA National Hurricane Center
to forecast surges that occur from wind and pressure forces of hurricanes, considers only storm surge height, and
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does not consider the effects of waves. The SLOSH spatial data includes boundaries for Category 1 through
Category 4 hurricane events.
To estimate exposure to the SLOSH Category 1 through Category 4 flood hazard areas, the spatial flood hazard
boundaries were overlaid on centroids of updated assets (population, building stock, critical facilities and
lifelines, and new development). Centroids that intersected the hazard areas were totaled to estimate the building
replacement cost value and population vulnerable to the storm surge inundation areas.
Tsunami
Best available data was used to assess Galveston County’s vulnerability to impacts from tsunamis. At this time,
the Hazus model does not assess tsunami risk to areas in the State of Texas. Therefore, a hazard area was
developed based upon the number of assets within 322 feet of a tsunami evacuation route. This area represents
the locations within the County that will experience the greatest amount of congestion to evacuate out of the
County due to a tsunami event. Asset data (population, building stock, critical facilities, and new development)
were used to support an evaluation of assets exposed and potential impacts and losses. To determine what assets
are at risk to impacts from tsunamis, the County’s assets were overlaid with the hazard area. Assets with their
centroid located within 322 feet of a tsunami evacuation route were totaled to estimate the number of persons,
buildings, and facilities at risk to impacts from tsunamis.
Wildfire
The Wildfire-Urban Interface (Interface and Intermix) obtained through the SILVIS Laboratory, Department of
Forest Ecology and Management, University of Wisconsin – Madison, was referenced to delineate wildfire
hazard areas. The University of Wisconsin – Madison wildland fire hazard areas are based on the 2010 Census
and 2006 National Land Cover Dataset and the Protected Areas Database. For this risk assessment, the high-,
medium-, and low-density interface areas were combined and used as the “Interface” hazard area, and the high-,
medium-, and low-density intermix areas were combined and used as the “Intermix” hazard areas.
Asset data (population, building stock, critical facilities, and new development) were used to support an
evaluation of assets exposed and potential impacts and losses. To determine what assets are at risk to impacts
from wildfires, the County’s assets were overlaid with the hazard area. Assets with their centroid located within
the wildfire hazard areas were totaled to estimate the number of persons, buildings, and facilities at risk to
impacts from wildfire events.
All Other Assessed Hazards
No GIS format datasets appropriate for an exposure analysis were identified for the following hazards: dam and
levee failure, drought, extreme temperature, hail, land subsidence, lightning, pandemic, thunderstorm wind,
tornadoes, and utility failure.
4.1.3 Sources of Data Used in Hazus Modeling and Exposure Analyses
Galveston County assets were identified to assess potential exposure and loss associated with the hazards of
concern. For the HMP update, Galveston County assessed exposure vulnerability of the following types of
assets: population, buildings, and critical facilities/infrastructure. Some assets may be more vulnerable because
of their physical characteristics or socioeconomic uses. To protect individual privacy and the security of critical
facilities, information on properties assessed is presented in aggregate, without details about specific individual
personal or public properties.
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Building and Cost Data
Replacement cost values and detailed structure information derived from parcel and tax assessor data provided
by the Galveston County Appraisal District were loaded into Hazus. An updated inventory was used in place of
the Hazus defaults for critical facilities and infrastructure.
Replacement cost is the cost to replace the entire structure with one of equal quality and utility. Replacement
cost is based on industry-standard cost-estimation models published in RS Means Square Foot Costs (RS Means,
2021). It is calculated using the RS Means square foot cost for a structure, which is based on the Hazus occupancy
class (i.e., multi-family residential or commercial retail trade), multiplied by the square footage of the structure
from the tax assessor data. The construction class and number of stories for single-family residential structures
also factor into determining the square foot costs.
Critical Facilities and Lifelines
The 2021 HMP critical facility inventory, which includes essential facilities, utilities, government offices,
transportation features and user-defined facilities was updated by the Planning Partnership. The update involved
a review for accuracy, additions, or deletions of new/moved critical assets, identification of backup power for
each asset (if known) and whether the critical facility is considered a lifeline in accordance with FEMA’s
definition. To protect individual privacy and the security of assets, information is presented in aggregate, without
details about specific individual properties or facilities.
Population
Total population statistics from the 2015-2019 ACS 5-year estimate were used to estimate the exposure and
potential impacts to the County’s population in place of the 2010 U.S. Census block estimates. Population counts
were evenly distributed by the number of residential buildings per municipality generated from the building
stock inventory used in the hazard mitigation plan update. This estimate is a more precise distribution of
population across the County compared to only using the Census block or Census tract boundaries. Limitations
of these analyses are recognized, and thus the results are used only to provide a general estimate for planning
purposes.
As discussed in Section 3 (County Profile), research has shown that some populations are at greater risk from
hazard events because of decreased resources or physical abilities. Vulnerable populations in Galveston County
included in the risk assessment are children, elderly, and population below the poverty level.
Hazus Data Inputs
The following hazard datasets were used for the Hazus Level 2 analysis conducted for the risk assessment:
• Flood—The FEMA 2019 effective Digital Flood Insurance Rate Map (DFIRM) and FEMA 2014
coastal hazard area depth grids for the planning area was used to delineate the coastal and riverine
flood hazard areas to estimate potential losses. Using the DFIRM floodplain boundaries and base
flood elevation information, and the USGS 1-meter digital elevation model data, flood depth grids
were generated and integrated into the Hazus model.
• Hurricane—Hazus hurricane probabilistic data were used for the analysis of this hazard.
Other Local Hazard Data
Locally relevant information on hazards was gathered from a variety of sources. Frequency and severity
indicators include past events and the expert opinions of geologists, emergency management specialists, and
others. Data sources for specific hazards were as follows:
• Coastal Erosion—NOAA 2011 CUSP Shoreline 100-foot buffer
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• Inland Erosion—USDA Natural Resources Conservation Service soils data where erosion factor (k)
is equal or greater than 0.49
• Storm Surge—NOAA 2014 storm surge data
• Sea Level Rise—NOAA 2017 sea level rise data
• Wildfire—Wildland Urban Interface (WUI) data was acquired from the University of Wisconsin
No GIS format datasets appropriate for an exposure analysis were identified for the following hazards: dam and
levee failure, drought, extreme temperature, hail, land subsidence, lightning, pandemic, thunderstorm wind,
tornadoes, and utility failure.
Data Source Summary
Table 4-1 summarizes the data sources used for the risk assessment for this plan.
Table 4-1. Data Sources
Data Source Date Format
Critical Facilities
Essential Government Functions
Government Offices; City of
Galveston; HIFLD; Texas
Commission on Environmental
Quality; Texas Tech University
2021/2021/2020/2021/2021 Digital (GIS) format
General Building Stock Galveston Central Appraisal District;
Microsoft Bing; RS Means 2021/2018/2021 Digital (GIS) format
Population data American Community Survey 5-year
Estimates 2019 Digital (GIS and
tabular) format
Digital Elevation Model USGS 2018 Digital (GIS) format
FEMA Effective DFIRM
Data FEMA 2018 Digital (GIS) format
Coastal Flood Hazard Area FEMA 2014 Digital (GIS) format
Coastal Erosion NOAA 2011 Digital (GIS) format
Inland Erosion USGS/NRCS 2020 Digital (GIS) format
Sea Level Rise NOAA 2017 Digital (GIS) format
SLOSH NOAA 2014 Digital (GIS) format
Wildfire University of Wisconsin 2010 Digital (GIS) format
Expansive Soils USGS/NRCS 2020 Digital (GIS) format
Tsunami Evacuation Routes Galveston County GIS 2021 Digital (GIS) format
4.1.4 Limitations
Loss estimates, exposure assessments, and hazard-specific vulnerability evaluations rely on the best available
data and methodologies. Uncertainties are inherent in any loss estimation methodology and arise in part from
incomplete scientific knowledge concerning natural hazards and their effects on the built environment.
Uncertainties also result from the following:
• Approximations and simplifications necessary to conduct a study
• Incomplete or outdated inventory, demographic or economic parameter data
• The unique nature, geographic extent, and severity of each hazard
• Mitigation measures already employed
• The amount of advance notice residents has to prepare for a specific hazard event.
These factors can affect loss estimates by a factor of two or more. Therefore, potential exposure and loss
estimates are approximate and should be used only to understand relative risk. Over the long term, Galveston
County will collect additional data to assist in estimating potential losses associated with other hazards.
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4.2 IDENTIFICATION OF HAZARDS OF CONCERN
To provide a strong foundation for mitigation actions considered in Sections 6
(Mitigation Strategy), Galveston County focused on considering a full range
of hazards that could impact the area and then identified and ranked those
hazards that presented the greatest concern. The hazard of concern
identification process incorporated input from the Steering Committee; review
of the State of Texas Hazard Mitigation Plan (2019); review of the 2017
Galveston County HMP; research and local, state, and federal information on
the frequency, magnitude, and costs associated with the various hazards that
have previously, or could feasibly, impact the region; and qualitative or anecdotal information regarding natural
(not manmade) hazards and the perceived vulnerability of the study area’s assets to them. Table 4.2-1 documents
the process of identifying the hazards of concern for further profiling and evaluation.
Other natural and human-caused hazards of concern have occurred within Galveston County, have a low
potential to occur and/or result in significant impacts within the County, or are covered in other plans that
specifically address technological and intentional hazards. Therefore, these hazards will not be further addressed
within this version of the plan. However, if deemed necessary by the County, these hazards may be considered
in future versions of the HMP.
4.2.1 Changes from the 2017 Hazard Mitigation Plan
Since the development of the last plan, hazards and disasters not assessed in the prior plan have occurred in the
County. These hazards were identified by stakeholders as areas to address in the plan.
The prior plan did not address pandemic as a hazard of concern. Beginning in March 2020, Galveston County
was hit with the COVID-19 pandemic along with the rest of the world. As of December 28, 2021, there were
58,824 confirmed cases in Galveston County and 588 deaths associated with the virus.
The prior plan only addressed extreme heat, but this update includes both heat and cold when addressing extreme
temperatures. This reflects the devastating cold event of February 2021.
The prior plan addressed coastal erosion as a single hazard. This update includes inland erosion in the profile.
The 2022 Galveston County Hazard Mitigation Plan Update includes best available data throughout the plan to
present an updated understanding the County’s risk.
4.2.2 Hazard Groupings
As per the 2017 Galveston County HMP, the Steering Committee maintained the grouping of hazards based on
the similarity of hazard events, typical concurrence or impacts, consideration of how hazards have been grouped
in FEMA guidance documents (FEMA 386-2 Understanding Your Risks, Identifying Hazards and Estimating
Losses; Multi-Hazard Identification and Risk Assessment – The Cornerstone of the National Mitigation Strategy;
Local Mitigation Planning Handbook), and consideration of hazard grouping in the State of Texas HMP.
The Coastal and Inland Erosion profile addresses erosion associated with water in Galveston
County.
The Dam and Levee Failure profile addresses dam/levee failures that may impact Galveston
County.
Hazards of Concern are
defined as those hazards
that are considered most
likely to impact a
community. These are
identified using available
data and local knowledge.
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The Drought hazard profile specifically addresses drought events that occurred in Galveston
County.
The Expansive Soils profile addresses expansive soil-related events that may occur in Galveston
County.
The Extreme Temperature hazard profile specifically addresses periods of extreme temperature
(heat and cold) that occurred in the County or had considerable impact on the County.
The Flood hazard includes riverine, flash flooding, coastal and stormwater flooding. Inclusion of
the various forms of flooding is consistent with that used in FEMA’s Multi-Hazard Identification
and Risk Assessment guidance.
The Hail hazard profile specifically addresses hail events that occurred in Galveston County.
The Hurricane and Tropical Storm profile addresses hurricanes and tropical storms that occurred
in or impacted Galveston County.
The Land Subsidence profile addresses land subsidence events occurring in Galveston County or
having impacts on the County.
The Lightning hazard profile specifically addresses lightning events that occurred in Galveston
County.
The Pandemic hazard profile addresses diseases with the potential to impact the County, including
the novel coronavirus (COVID-19), West Nile Virus, and Influenza.
The Severe Winter Storm profile includes heavy snow, blizzards, and ice storms. This grouping is
consistent with the State of Texas HMP.
The Thunderstorm Wind hazard profile specifically addresses thunderstorm events that occurred in
Galveston County.
The Tornado hazard profile specifically addresses tornado events that occurred in Galveston
County.
The Tsunami profile addresses the potential for events that may occur in Galveston County.
The Utility Failure profile includes events related to power outages in Galveston County.
The Wildfire profile addresses wildfire events that occurred in Galveston County.
Table 4-2. Identification of Hazards of Concern for Galveston County
Hazard Description
Natural Hazards
Coastal and
Inland Erosion
• Coastal erosion impacts the jurisdictions in Galveston County that border the Gulf or tidal waterway.
• Inland erosion is common along the streams and bayous.
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Hazard Description
• Inland and coastal erosion are identified as hazards of concern in the 2018 State of Texas Hazard
Mitigation Plan; however, they were profiled individually.
• Due to the history of occurrence in the County, the coastal and inland erosion hazard is identified as a
hazard of concern for Galveston County.
Dam and
Levee Failure
• According to the National Inventory of Dams, there is 1 major dam dams in Galveston County. It is
classified as a high hazard dam.
• The identified dam is for water supply purposes and was built in 1949.
• The Galveston County hurricane flood protection levee protects the cities of Texas City and La
Marque. The levee is comprised of 15.7 miles of an earthen berm and 1.3 miles of concrete wall,
offering a total of 17 miles of protection.
• There have been no reported dam or levee incidents in the County.
• Due to the high hazard dam and the levee system located in the County, dam and levee failure was
identified as a hazard of concern for the county.
• The 2018 State of Texas HMP includes dam/levee failure as a hazard of concern for the State.
Drought • Galveston County was the subject of seven USDA declarations for drought that occurred between
2012 and 2021.
• Due to the history of occurrence and the impacts drought can have, drought was identified as a hazard
of concern for Galveston County.
Earthquake • The 2018 State of Texas HMP includes earthquakes as a hazard of concern for the State; however,
due to the lack of earthquake events in the County and the unlikely possibility of future events,
earthquake is not identified as a hazard of concern for Galveston County.
Expansive
Soils
• According to the 2018 State of Texas HMP, Galveston County is underlaid by soils with a high
potential for swelling.
• Groundwater withdrawal will continue to increase the risk for expansive soil issues. An increase in
development will increase the need for groundwater.
• While portions of the County are underlaid by expansive soils, Galveston County has insufficient
data on losses and no record of impacts from expansive soils.
Extreme
Temperature
• Extreme heat and extreme cold temperatures were identified as hazards of concern in the State of
Texas HMP; however, they were profiled individually.
• Galveston County has been impacted by eight heat events and three cold events between 1996 and
2021.
• Galveston County has experienced extreme heat and cold events and will continue to experience
them in the future. Therefore, extreme temperature was identified as a hazard of concern for the
County.
Flood • Riverine and coastal flooding are identified as hazards of concern in the 2018 State of Texas Hazard
Mitigation Plan; however, they were profiled individually.
• 96 flood events have been identified as occurring in Galveston County between 1996 and 2020. The
flood events have resulted in six FEMA disaster declarations.
• As of September 2021, there are 58,956 flood insurance policies in force and claims that have totaled
over $2.1 million since 1970.
• The State HMP indicated that Galveston County is located in one of the storm surge basins and has a
large percentage of land inside the SFHA. The County will continue to experience flood events.
• Based on the history of events and losses, flooding was identified as a hazard of concern for
Galveston County.
Hail • Hailstorms were identified as a hazard of concern in the 2018 Texas State Hazard Mitigation Plan.
• Galveston County was not subject to a hail-related major disaster/emergency declaration; however,
the County has been subject to a number of hail events since 1996. There is a 100% chance of the
County being impacted by a hail event during a given year.
• Hail was identified as a hazard of concern for Galveston County.
Hurricanes,
Tropical
Storms, and
Depressions
• Hurricanes and tropical storms were identified as a hazard of concern in the 2018 State Hazard
Mitigation Plan.
• Galveston County was included in 14 of 29 hurricane-related major disaster and emergency
declarations. Since 1996, there have been 19 tropical storm/hurricane events.
• Based on history of occurrences and losses, the hazard was identified as a hazard of concern for
Galveston County.
Land
Subsidence
• Land subsidence was identified as a hazard of concern in the State Hazard Mitigation Plan. The State
HMP indicates that Galveston County is located within a coastal lowlands aquifer system area of the
State that is vulnerable to land subsidence.
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Hazard Description
• There have been no impacts to any critical facilities, infrastructure, or other community assets. Rates
of subsidence have decreased across Galveston County, but its effects continue to compound.
Lightning • Lightning was identified as a hazard of concern in the 2018 State Hazard Mitigation Plan.
• Lightning is a somewhat frequent occurrence in the County. However, based on available data, there
have been only 20 reported events since 1996 causing over $3.5 million in property damage, five
fatalities, and three injuries.
• The hazard was identified as a hazard of concern for Galveston County.
Pandemic • Galveston County has experienced three separate public health events since 2003. These includes
include West Nile Virus, Zika Virus, and COVID-19.
• At the time of this plan’s writing, COVID-19 continues to impact public health both locally and
globally.
• The hazard was identified as a Hazard of Concern for Galveston County.
Severe Winter
Storm
• Winter weather was identified as a hazard of concern in the State Hazard Mitigation Plan.
• Galveston County has infrequently been impacted by ice storms and heavy snow, but property
damages have been in the millions of dollars.
• The hazard was identified as a Hazard of Concern for Galveston County.
Thunderstorm
Wind
• Severe Winds were identified as a hazard in the State Hazard Mitigation Plan.
• For this plan, Severe Winds were included as part of the Thunderstorm Wind hazard.
• Galveston County has been subject to two thunderstorm-related major disaster declarations and more
than 200 events since 1950.
• The hazard was identified as a Hazard of Concern for Galveston County.
Tornadoes • The Texas State Hazard Mitigation Plan identified tornadoes as a state hazard of concern.
• Galveston County has not been the subject and tornado-related FEMA disaster declarations; however,
54 funnel clouds and 124 tornadoes have occurred in the County since 1950, causing over $36
million in property damage, 9 fatalities, and 243 injuries.
• The hazard was identified as a Hazard of Concern for Galveston County.
Tsunami • The 2018 State of Texas HMP does not list tsunami as a hazard of concern for the State; however, the
2017 Galveston County HMP included it for the County.
• There has been one small wave tsunami event recorded in the County over 100 years ago in 1918.
• The hazard was identified as a Hazard of Concern for Galveston County.
Wildfire • The Texas State Hazard Mitigation Plan identified wildfires as a state hazard of concern.
• While wildfires have occurred in the County, Galveston County has insufficient data on losses and no
record of impacts from wildfires.
• The wildfire hazard was identified as a Hazard of Concern for Galveston County.
Non-Natural Hazards
Utility Failure • Power failures are usually the result of a natural hazard event involving high winds.
• Power failure is especially problematic for homes that are cooled or heated by electricity and for
residents who rely on power for home medical devices.
• The hazard was identified as a Hazard of Concern for Galveston County.
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4.3 HAZARD PROFILES
4.3.1 Erosion
The following section provides the hazard profile and vulnerability assessment for the erosion hazard in
Galveston County.
Hazard Profile
Description
Erosion is the process of the wearing away of beaches and bluffs along the coastline by large storms, flooding,
strong wave action, sea level rise, fluvial currents, and human activities. In the State of Texas, there are two
types of erosion: coastal erosion and inland erosion.
Coastal Erosion
Coastal erosion is a hydrologic hazard defined as the wearing away of land and loss of beach, shoreline, or dune
material because of natural coastal processes or manmade influences. Coastal erosion is linked to hurricane
damage in that healthy coastal dunes and beaches help reduce impacts of hurricane, tropical storms, tropical
depressions, and severe coastal flooding. Mitigating coastal erosion also mitigates those hazards (State of Texas
Hazard Mitigation Plan 2018).
Erosion is measured as a rate of change in the position or displacement of a shoreline over a period of time.
Short-term erosion typically results from periodic natural events, such as wave action, storm surges and wind.
Long-term erosion is a result of repetitive occurrences of this type and of severe storm and flooding events.
Erosion can affect natural and built environments. Impacts depend on topography, soils, building types and
construction materials. Coastal erosion can affect natural systems, coastal food supplies, tourism industry, and
small town viability. When sea water infiltrates freshwater wetlands, they can die, removing key habitats for
animals and a protective buffer for nearby communities (State of Texas Hazard Mitigation Plan 2018).
The most vulnerable jurisdictions in Texas are the cities and
towns along the coast and barrier islands in Region 2, Region
3, and Region 6. The planning area is in Region 2 and
therefore especially vulnerable to coastal erosion.
See Figure 4-2 for shoreline movement rates. Mitigation
techniques include dune and beach restoration, building
seawalls, and placing semi-permanent obstructions
perpendicular to beaches. Coastal erosion mitigation actions
have the benefit of helping reduce impacts from hurricanes
and severe coastal flooding. The Texas General Land Office
(GLO) manages coastal erosion and documents its progress
to the legislature in Coastal Erosion Planning and Response
Act reports.
Figure 4-1 Texas Regions
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Figure 4-2 Texas Shoreline Movement Rate Map
Source: (Bureau of Economic Geology, University of Texas 2012)
Inland Erosion
Inland erosion is the wearing-away of soil or removal of the banks of streams or rivers. It involves the breakdown,
detachment, transport, and redistribution of soil particles by forces of water, wind, or gravity. Soil erosion on
cropland is of particular interest because of its onsite impacts on soil quality and crop productivity, and its off-
site impacts on water quantity and quality, air quality, and biological activity. Erosion is measured as a rate of
change in the position or displacement of a river or stream bank over a period of time or the amount of soil
removal. Short-term erosion results from periodic flooding and wind. Long-term erosion is a result of repetitive
events of this type and of prolonged drought.
In the State of Texas, inland erosion is more prominent in the High Plains, Rolling Plains, and Coastal Sand
Plains. Galveston County is located in the Gulf Coast Prairies & Marshes ecoregion and therefore inland erosion
is not as prominent as coastal erosion (Figure 4-3).
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Figure 4-3. Location of Erosion Areas in the State of Texas
Source: Kids on the Land, 2021
Erosion caused by water is the primary concern for the County. Water erosion is the detachment and removal
of soil by water. The process can occur naturally or be accelerated by human activity. The rate of erosion can
be a slow process that continues relatively unnoticed or can occur very rapidly. The rate is dependent on the
type of soil, the local landscape, and weather conditions (Ritter 2018, USDA 2000).
There are three types of water erosion that can occur: sheet, rill, and gully. Sheet erosion is the most difficult to
see as it is a uniform soil layer being remove from an area over the surface. Rill erosion starts as water flowing
over the soil surface concentrates into small streams, creating channels of water flow. Gully erosion is when rill
erosion is not kept under control and creates gullies (deeper and wider cuts) (Soil Science Society of America
n.d.)
Erosion can be most severe where urbanization, development, recreational activities, logging, and agricultural
practices take place. Extreme rainfall events, lack of vegetative cover, fragile soils and steep slopes combine to
accelerate erosion (Ritter 2018).
Location
Coastal Erosion
Coastal erosion impacts the jurisdictions in Galveston County that border the Gulf or tidal waterway. These
include Clear Lake Shores, Hitchcock, Jamaica Beach, Kemah, Tiki Island, and the unincorporated areas of
Galveston County (Galveston County 2017).
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Inland Erosion
The Dickinson Bayou watershed encompasses approximately 100 square miles of land that drains water into the
bayou. Vegetated riparian zones are an important component of the bayous that provide functional and aesthetic
values. Vegetated shorelines minimize soil erosion and naturally increase filtration of surface water runoff. In
many areas of the watershed, Dickinson Bayou has little natural riparian buffer left (Dickinson Bayou Watershed
Partnership n.d.).
The Highland Bayou Coastal Basin is a 120 square mile drainage basin located on mainland Galveston County.
Bayou and stream segments consist of non-tidal, tidally influenced, and tidal waters. Fresh water in the bayous
is largely precipitation-driven overland flows (Texas A&M AgriLife Extension n.d.). Even though the
topography is flat, overland flows can cause erosion in basin.
Extent
Coastal Erosion
Galveston County has approximately 55 miles of Gulf shoreline and 291 miles of Bay shoreline. As shown in
Figure 4-2, the jurisdictions located on the Gulf of Mexico have experienced substantial land loss along the
shoreline. According to the Texas General Land Office, the Texas coast is eroding at 4.0 feet per year (Texas
General Land Office 2015).
Inland Erosion
It is difficult to directly measure erosion and the risk of erosion. There are other properties, however, that can
be used to measure erosion: soil surface stability, aggregate stability, infiltration, compaction, and content of
organic matter. Measuring these properties can help with understanding the susceptibility of erosion at a specific
location. Comparing visual observations along with quantitative measurements can help provide information
about soil surface stability, sedimentation, and soil loss (USDA 2001).
Every five years the Natural Resources Conservation Service conducts a statistical survey of natural resource
conditions and trends on non-federal land in the United States called the National Resources Inventory (NRI).
The NRI provides nationally consistent statistical data on erosion resulting from water and wind processes on
cropland. It uses a variety of tables and maps to document the ongoing state of erosion across the count y (State
of Texas Hazard Mitigation Plan 2018, NRCD 2010).
One key measure used in the NRI is the Erodibility Index (EI). This index is a numerical expression of the
potential of a soil to erode, considering climatic factors and the soils’ physical and chemical properties. The
higher the index, the greater is the investment needed to maintain the sustainability of the soil resource base of
high-yield crops. Highly Erodible Land is defined to have an EI of at least 8 (State of Texas Hazard Mitigation
Plan 2018).
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Figure 4-4. National Erosion Loss Rates
Source: NRI 2007
Another soil erosion component is the soil loss tolerant rate. Identified as ‘T’, this is the maximum rate of annual
soil loss that will permit crop productivity to be economically sustained. Erosion is considered to be greater than
‘T’ if either water or wind erosion rates exceed the soil tolerance rate (State of Texas Hazard Mitigation Plan
2018). Figure 4-4 illustrates the locations of where erosion exceeded the soil loss tolerance rates across the
United States. Each red dot represents 100,000 tons of erosion above the soil loss tolerance. According to this
figure, areas of erosion exceeding the soil loss tolerance rates was not identified in Galveston County.
Worst-Case Scenario
Magnitude scales for erosion events do not currently exist, but any storm that produces significant amounts of
rain in a short period of time could lead to a worst-case scenario for an erosion incident along the shoreline or
the bayous of Galveston County. Storms that occur in rapid succession similar to the events that occurred in
August and September 2020 (see Table 4-3) may cause several feet of dune and bayou erosion to occur, similar
to those previous events. Additionally, hurricane winds can create wave action that quickly erodes shoreline
areas. Rainfall events that occur upstream from the bayous can create flood stages and high flow rates. This
causes the water to move at higher speeds through the County, causing erosion along the banks of the bayous.
Impacts from such events includes road closures, damage to infrastructure and buildings, and inaccessible areas
that can disrupt emergency response.
Previous Occurrences and Losses
Between 1953 and 2021, the State of Texas was not included in any erosion-related FEMA disaster declarations.
For this plan update, there was limited information regarding inland erosion in Galveston County. Statistical
data for individual erosion events is not readily available, however the following events were identified as coastal
erosion events associated with severe weather events.
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Table 4-3. Severe Storm/Erosion Events for Galveston County, 2003-2021
Start Date of Event Event Type Event Details
July 14, 2003 Hurricane Claudette The highest recorded tide level, 7.56 ft. above mean low‐lower
water, was recorded at Pleasure Pier in Galveston.
September 23, 2005 Hurricane Rita
In Galveston County, tropical storm force sustained winds with
gusts to hurricane force were reported across the county,
especially on the Bolivar Peninsula.
November 15, 2006 High Winds
A strong cold front moved through Southeast Texas in the
morning. A tight surface pressure gradient behind the front
produced winds at wind advisory levels with some higher gusts
observed at Bacliff.
September 12, 2007 Hurricane Humberto
Developed from a tropical depression into a hurricane within
nineteen hours. Maximum rainfall totals from Humberto ranged
from around two inches to over fourteen inches mainly along and
east of a line from Freeport to the Hitchcock and Texas City area
to around Winnie.
September 5, 2008 Tropical Storm Edouard
Storm tide damage on the Bolivar Peninsula was confined to the
Gilchrist area. Ten single family homes experienced flooding up
to eighteen inches deep inside the home. Fifteen single family
homes and two mobile homes experienced flooding up to six
inches deep inside the home.
September 12, 2008 Hurricane Ike
Ike produced damage due to high storm surge and high winds
along Galveston Island, the Bolivar Peninsula, and along the
Galveston Bay. Storm tides of 10 to 15 feet above mean sea level
were observed in these areas.
April 24, 2010 High Winds
A low-pressure system combined with a gravity wave disturbance
produced a period of strong winds mainly along the coast. Wind
gusts were in excess of 69 mph.
September 3, 2011 High Surf High offshore winds associated with Tropical Storm Lee impacted
areas of Galveston County.
June 15, 2015 Tropical Storm High surf caused erosion of Galveston Island beaches during
Tropical Storm Bill.
June 21, 2017 Tropical Storm Coastal flooding occurred in connection with Tropical Storm
Cindy.
August 26, 2017 Hurricane Harvey Hurricane Harvey produced major flooding throughout the
County.
August 26, 2020 Storm Surge/Tide Storm surge flooding and high surf associated with Hurricane
Laura. Beach erosion on both the Gulf and Bay sides.
September 23, 2020 Storm Surge/Tide
Storm surge flooding and high surf associated with Tropical Storm
Beta. Significant beach erosion occurred along the Bolivar
Peninsula and Galveston Island.
October 8, 2020 Tropical Storm Hurricane Delta produced high surf and elevated tides along Gulf
facing beaches and around Galveston Bay.
Source: NOAA-NCEI 2021, Galveston County HMP 2017
Note: Due to limitations in data, not all erosion events are accounted for in the tally of occurrences. As a result, the number of hazard
occurrences is underestimated
Climate Change Projections
Climate change may impact storm patterns, increasing the probability of more frequent, intense storms with
varying duration. Increase in global temperature could affect the snowpack and its ability to hold and store water.
Warming temperatures also could increase the occurrence and duration of droughts, which would increase the
probability of wildfire, reducing the vegetation that helps to support steep slopes. All of these factors would
increase the probability for erosion to occur.
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Probability of Future Events
It is anticipated that erosion will continue to occur along the shoreline and bayous of Galveston County. As the
frequency of storms occur due to climate change, the probability for future events will likely increase as well.
Table 4-4 summarizes data regarding the probability of occurrences of erosion events in the County based on
the historic record. The information used to calculate the probability of occurrences is based on the 2017
Galveston HMP, the NOAA-NCEI Storm Events Database, and FEMA.
Table 4-4 Probability of Future Occurrence of Erosion Events
Hazard Type Number of Occurrences Between 2003 and 2020 % chance of occurrence in any given year
Erosion 14 77.8%
Based on the 14 recorded erosion events over 17 years, the planning area averages nearly one erosion event
every year. Based on the history of events, the probability for erosion events occurring in the County is
considered occasional (between 10 and 100% annual chance of occurring). Refer to Section 4.4 for additional
information on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To assess Galveston County's risk to the coastal and inland erosion hazards, a spatial analysis was conducted
using the best available data. To help understand the geographic distribution of the County’s risk to coastal
erosion, a 100-foot buffer was created from NOAA’s 2011 shoreline. The inland erosion hazard area was
determined using USDA’s Natural Resources Conservation Service’s 2020 soil data for Galveston County. Soils
with an erodibility factor (k) of 0.49 or greater were extracted to assess the County’s risk to inland erosion.
Figure 4-5 depicts these hazard areas in the County.
Refer to Section 4.1 (Methodology and Tools) for additional details on the methodology used to assess coastal
and inland erosion risk.
Impact on Life, Health and Safety
Coastal and inland erosion is not generally considered an imminent threat to public safety when the changes are
gradual over many years. However, drastic changes to the shoreline may occur as a result of a single storm event
which can threaten homes and public safety. Furthermore, erosion can cause damage to residential buildings,
displace residents, and block major roadways, thus inhibiting travel for emergency responders or populations
trying to evacuate the area.
Erosion can create water quality problems in surface waters and drainage ways. These problems can adversely
impact the health and biological diversity of water bodies. According to the USDA, this includes:
• Excess nutrients impact water quality through eutrophication, a process where excess nitrogen and
phosphorus causes unwanted biological growth in water bodies.
• Sediment reduces water quality by making the water cloudy. Turbidity prevents sunlight from
penetrating the water and reduces photosynthesis and underwater vegetation. Oxygen levels are reduced
in turbid waters, further degrading habitat for fish and other aquatic organisms.
• Sediment can build up in stream channels, lowering flow capacity. The problem of low stream capacity
is compounded as runoff increases from newly built-up or paved areas and causes stream channels to
receive larger amounts of water in shorter periods of time. This leads to more frequent flooding in areas
that never or only rarely flooded in the past. In flood prone areas, levees may need to be built or enlarged
to better protect public safety.
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• A financial burden results from cleanup of sediment-damaged areas. Taxpayers often bear the cost of
removing sediment from public roads, road ditches, culverts, or streams; not to mention damage to
homes and the safety hazards associated with flooding. Other costs of erosion that are borne by the
public are degraded soils, a polluted environment, more runoff, greater need for irrigation, and
aesthetically unpleasing sites (USDA 2000).
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Figure 4-5. Erosion Hazard Areas in Galveston County, TX
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The population exposed, or located in the estimated hazard area, is considered vulnerable to this hazard. The
analysis indicates that 5,049 people are located in the estimated coastal erosion hazard area, and a total of 42,644
are located in the inland erosion hazard area (Table 4-5).
Table 4-5. Estimated Population Located in the Coastal Erosion Hazard Area
Jurisdiction
Total Population
(American
Community
Survey 2015-
2019)
Estimated Population Located in the Erosion Hazard Areas
Number of Persons
Located in the Coastal
Erosion Hazard Area
Percent
of Total
Number of
Persons Located
in the Inland
Erosion Hazard
Area
Percent
of Total
Clear Lake Shores (C) 1,258 66 5.2% 0 0.0%
Dickinson (C) 20,847 0 0.0% 20 0.1%
Friendswood (C) 41,213 0 0.0% 3,791 9.2%
Hitchcock (C) 7,301 170 2.3% 3,770 51.6%
Jamaica Beach (C) 1,078 1 0.1% 0 0.0%
Kemah (C) 1,807 20 1.1% 344 19.0%
La Marque (C) 18,030 0 0.0% 1,686 9.4%
League City (C) 114,392 2,258 2.0% 15,118 13.2%
Santa Fe (C) 12,735 0 0.0% 4,938 38.8%
Bayou Vista (C) 1,763 0 0.0% 0 0.0%
Tiki Island (V) 1,106 973 88.0% 0 0.0%
Galveston County (Total) 350,682 5,049 1.4% 37,595 10.7%
Source: ACS 5-year Estimate 2015-2019; NOAA 2011 (100 foot buffer from CUSP Shoreline), USDA/NRCS 2020 (K factor >0.49)
Note (1): C = City, V = Village, % = Percent, < = Less Than
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County. RCV =
Land Use and Population Trends
Impact on General Building Stock
After considering the population exposed and potentially vulnerable to the coastal and inland erosion, the built
environment was evaluated. Erosion can impact structures located along the banks of waterways, having the
potential to destabilize the foundation of structures. It can also impact infrastructure such as dams, levees, roads,
and other developed land. Table 4-6 and Table 4-7 summarizes the results of the vulnerability analysis regarding
erosion in Galveston County.
In summary, 4,922 buildings accounting for approximately $6.07 billion of replacement cost value are located
in the estimated coastal erosion hazard area (Table 4-6). In total, this represents about nearly 4% percent of the
County's total general building stock inventory. Furthermore, 21,966 structures (approximately $16.5 billion)
are located in inland erosion hazard area (Table 4-7).
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Galveston County, TX | Hazard Mitigation Plan 4-22
2022 Update
Table 4-6. Estimated Buildings Located in the Coastal Erosion Hazard Area
Jurisdiction
Total
Number
of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located in the Coastal Erosion Hazard
Areas
Number of
Buildings
Located in
the Coastal
Erosion
Hazard Area
Percent of
Total
Total Replacement
Cost Value of
Buildings Located in
the Coastal Erosion
Hazard Area
Percent
of Total
Clear Lake
Shores (C) 1,155 $904,562,368.66 76 6.6% $66,169,833 7.3%
Dickinson (C) 10,351 $6,601,710,645.63 0 0.0% $0 0.0%
Friendswood (C) 14,891 $10,815,456,384.12 0 0.0% $0 0.0%
Hitchcock (C) 5,452 $4,592,036,651.86 112 2.1% $57,463,776 1.3%
Jamaica Beach
(C) 1,291 $458,205,838.82 5 0.4% $12,472,408 2.7%
Kemah (C) 1,634 $2,631,702,105.60 35 2.1% $164,157,938 6.2%
La Marque (C) 10,749 $7,927,292,522.28 0 0.0% $0 0.0%
League City (C) 46,742 $31,237,974,594.10 926 2.0% $846,109,429 2.7%
Santa Fe (C) 7,942 $4,831,628,162.13 0 0.0% $0 0.0%
Bayou Vista (C) 1,365 $445,354,087.33 0 0.0% $0 0.0%
Tiki Island (V) 868 $365,209,145.44 750 86.4% $303,617,859 83.1%
Galveston
County (Total) 209,947 $166,321,604,688.46 4,922 2.3% $6,077,155,937 3.7%
Source: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021, NOAA 2011 (100 foot buffer from CUSP Shoreline)
Note (1): C = City, V = Village, % = Percent, < = Less Than
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County. RCV =
Land Use and Population Trends
Table 4-7. Estimated Buildings Located in the Inland Erosion Hazard Area
Jurisdiction
Total
Number
of
Buildings
Total
Replacement Cost
Value (RCV)
Estimated Building Stock Located in the Inland Erosion Hazard
Areas
Number of
Buildings
Located in
the Inland
Erosion
Hazard Area
Percent
of Total
Total Replacement Cost
Value of Buildings
Located in the Inland
Erosion Hazard Area
Percent
of Total
Clear Lake Shores
(C) 1,155 $904,562,368.66 14 1.2% $245,995,024 27.2%
Dickinson (C) 10,351 $6,601,710,645.63 9 0.1% $4,507,445 0.1%
Friendswood (C) 14,891 $10,815,456,384.12 1,451 9.7% $1,514,963,977 14.0%
Hitchcock (C) 5,452 $4,592,036,651.86 2,715 49.8% $1,928,182,025 42.0%
Jamaica Beach (C) 1,291 $458,205,838.82 0 0.0% $0 0.0%
Kemah (C) 1,634 $2,631,702,105.60 320 19.6% $739,122,117 28.1%
La Marque (C) 10,749 $7,927,292,522.28 1,016 9.5% $738,400,989 9.3%
League City (C) 46,742 $31,237,974,594.10 6,315 13.5% $4,032,743,676 12.9%
Santa Fe (C) 7,942 $4,831,628,162.13 3,030 38.2% $1,786,356,664 37.0%
Bayou Vista (C) 1,365 $445,354,087.33 0 0.0% $0 0.0%
Tiki Island (V) 868 $365,209,145.44 0 0.0% $0 0.0%
Galveston County
(Total) 209,947 $166,321,604,688.46 21,966 10.5% $16,543,834,687 9.9%
Source: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021, USDA/NRCS 2020 (K factor >0.49)
Note (1): C = City, V = Village, % = Percent, < = Less Than
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Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County. RCV =
Land Use and Population Trends
Impact on Critical Facilities and Lifelines
Coastal erosion and sea level rise may potentially impact critical facilities and lifelines identified within the
County. Critical services may not be available if critical facilities or lifelines are directly damaged or
transportation routes to access these critical facilities are breached due to erosion. Erosion may des tabilize the
roadways leading to facilities or destroy the foundation that supports the critical facilities along the shoreline.
Table 4-8. Estimated Critical Facilities and Lifelines in the Coastal Erosion Hazard Areas
Jurisdiction
Total
Number of
Critical
Facilities
Total
Number of
Lifelines
Number of Critical Facilities and Lifeline Facilities Located
in the Coastal Erosion Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent of
Total
Lifelines
Clear Lake Shores (C) 24 24 15 62.5% 15 62.5%
Dickinson (C) 91 83 0 0.0% 0 0.0%
Friendswood (C) 96 82 0 0.0% 0 0.0%
Galveston (C) 691 671 63 9.1% 63 9.4%
Hitchcock (C) 214 212 2 0.9% 2 0.9%
Jamaica Beach (C) 11 11 0 0.0% 0 0.0%
Kemah (C) 15 14 2 13.3% 2 14.3%
La Marque (C) 121 107 0 0.0% 0 0.0%
League City (C) 321 283 19 5.9% 19 6.7%
Santa Fe (C) 135 128 0 0.0% 0 0.0%
Bayou Vista (C) 5 5 0 0.0% 0 0.0%
Tiki Island (V) 7 7 1 14.3% 1 14.3%
Galveston County
(Total) 2,437 2,317 175 7.2% 175 7.6%
Source: Essential Government Functions Government Offices 2021; City of Galveston 2021; HIFLD 2020; Texas Commission on
Environmental Quality 2021; Texas Tech University 2021; NOAA 2011 (100 foot buffer from CUSP Shoreline); USDA/NRCS 2020 (K
factor >0.49)
Note (1): C = City, V = Village, % = Percent, < = Less Than
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County. RCV =
Land Use and Population Trends
Table 4-9. Estimated Critical Facilities and Lifelines in the Inland Erosion Hazard Areas
Jurisdiction
Total
Number
of Critical
Facilities
Total
Number
of
Lifelines
Number of Critical Facilities and Lifeline Facilities Located
in the Inland Erosion Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent of
Total
Lifelines
Clear Lake Shores (C) 24 24 2 8.3% 2 8.3%
Dickinson (C) 91 83 0 0.0% 0 0.0%
Friendswood (C) 96 82 16 16.7% 14 17.1%
Hitchcock (C) 214 212 39 18.2% 39 18.4%
Jamaica Beach (C) 11 11 0 0.0% 0 0.0%
Kemah (C) 15 14 10 66.7% 10 71.4%
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Jurisdiction
Total
Number
of Critical
Facilities
Total
Number
of
Lifelines
Number of Critical Facilities and Lifeline Facilities Located
in the Inland Erosion Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent of
Total
Lifelines
La Marque (C) 121 107 9 7.4% 8 7.5%
League City (C) 321 283 60 18.7% 47 16.6%
Santa Fe (C) 135 128 53 39.3% 50 39.1%
Bayou Vista (C) 5 5 0 0.0% 0 0.0%
Tiki Island (V) 7 7 0 0.0% 0 0.0%
Galveston County (Total) 2,437 2,317 231 9.5% 211 9.1%
Source: Essential Government Functions Government Offices 2021; City of Galveston 2021; HIFLD 2020; Texas Commission on
Environmental Quality 2021; Texas Tech University 2021; NOAA 2011 (100 foot buffer from CUSP Shoreline); USDA/NRCS 2020 (K
factor >0.49)
Note (1): C = City, V = Village, % = Percent, < = Less Than
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County. RCV =
Land Use and Population Trends
Impact on Economy
The impact of erosion on the economy and estimated dollar losses are difficult to measure. Erosion and other
geological hazards can impose direct and indirect impacts on society. Erosion directly causes damages to
buildings. The total replacement cost value of structures located in the coastal and inland erosion hazard areas
in Galveston County is $22.6 billion ($6.08 billion coastal and $16.5 billion inland).
Coastal and inland erosion can cause extensive damage to public utilities and disruptions to delivery of services.
Loss of power and communications may occur and drinking water and wastewater treatment facilities may be
temporarily out of operation. Additionally, disruption to business operations can occur in cases where
infrastructure is breached by erosion. Loss of income may occur as a secondary impact if businesses are closed
under repairs due to this breaching. To prevent these potential business losses, public expenditures may need to
be spent to implement shoreline stabilizers and to protect key infrastructure like highways and interstates that
follow along the coastline. Furthermore, erosion may result in additional clean-up costs, reduced property values,
and loss of productivity, all of which are difficult to measure (USGS 2003).
Impact on the Environment
Erosion is a natural or man-made process that can greatly impact the environment. Sediment transferred through
streams, lakes, rivers can erode soil and impact ecosystems. High sediment concentrations can benefit the
environment by retaining dead plant production and capturing suspended sediment (Delaware Estuary Regional
Sediment Management Plan Workbook 2013). Alternatively, upland erosion can degrade water quality and
quantity, ultimately impacting aquatic life. Negative overall impacts to the environment occur when erosion
eliminates or contaminates critical habitats. For instance, filter-feeding bivalves consume small particles, which,
if contaminated from erosion runoff, could kill them (Kreeger et al. 2010).
FEMA estimates that every dollar spent on erosion control and mitigation to preserve wetlands and other natural
ecosystems provides a return on average of four dollars in cost-savings for the future. Preliminary studies
following Hurricane Harvey indicated this ration will increase from 1:4 to 1:6. Without healthy beaches, dunes
and wetlands to protect the coast, there is more day-to-day wear and the impact of major storms and hurricanes
is far more severe (Texas HMP 2018).
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2022 Update
Future Changes That May Impact Vulnerability
Understanding future changes that affect vulnerability can assist in planning for future development and ensure
establishment of appropriate mitigation, planning, and preparedness measures. The County considered the
following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change
Projected Development
As discussed, and illustrated in Section 3 (County Profile), areas targeted for future growth and development
have been identified across the County. Any areas of growth could be affected by erosion if the growth areas are
within identified hazard areas. Areas targeted for potential future growth and development could be potentially
impacted by erosion if they are located within areas prone to erosion
Projected Changes in Population
Increasing population trends in the Texas coastal region will directly increase the risks associated with coastal
erosion. A larger population will require additional structures to be constructed on land that is eroding in the
coastal regions. Coastal erosion does not pose a risk to loss of life, but the structures built on the coast will
require constant maintenance costs due to the continually loss of the coastal shorelines in Texas.
Climate Change
A direct impact of climate change on erosion is difficult to determine. Multiple secondary effects of climate
change have the potential to increase the likelihood of erosion. Warming temperatures resulting in wildfires
would reduce vegetative cover along steep slopes and destabilize the soils due to destruction of the root system;
increased intensity of rainfall events would increase saturation of soils on steep slopes.
Change of Vulnerability Since 2017 HMP
Since the 2017 analysis, population statistics have been updated using the 2015-2019 American Community
Survey population data. RS Means 2021-dollar values were used to develop a structure-level building inventory
and estimate replacement cost value for each building. The 2017 critical facility and lifeline inventory was also
reviewed and updated by the Planning Partnership. Furthermore, a coastal erosion hazard area and inland erosion
hazard area were generated using a 100-foot buffer from NOAA’s Continually Updated Shoreline Product
(CUSP) and soils with a K factor of great than 0.49 from the NRCS soil survey for Galveston County. These
changes provide an up-to-date look at the entire building stock for Galveston County and gives more accurate
results for the exposure and loss estimation analysis.
4.3.2 Dam and Levee Failure
The following section provides the hazard profile and vulnerability assessment for the dam and levee failure
hazard for Galveston County.
Profile
Hazard Description
Dams
A dam is an artificial barrier that has the ability to store water, wastewater, or liquid-borne materials for many
reasons—flood control, human water supply, irrigation, livestock water supply, energy generation, containment
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of mine tailings, recreation, or pollution control. Many dams fulfill a combi nation of these functions. They are
an important resource in the United States (Association of State Dam Safety Officials 2021).
Dams can be classified according to their purpose, the construction material or methods used, their slope or
cross-section, the way they resist the force of the water pressure, or the means used for controlling seepage.
Materials used to construct dams include earth, rock, tailings from mining or milling, concrete, masonry, steel,
timber, plastic, rubber, and combinations of these.
Dam failures typically occur when spillway capacity is inadequate and excess flow overtops the dam, or when
internal erosion (piping) through the dam or foundation occurs. Complete failure occurs if internal erosion or
overtopping results in a complete structural breach, releasing a high-velocity wall of debris-filled water that
rushes downstream, damaging anything in its path. Dam failures in the United States typically occur in one of
four ways:
• Overtopping of the primary dam structure, which accounts for 34 percent of all dam failures, can occur
due to inadequate spillway design, settlement of the dam crest, blockage of spillways, and other factors.
• Foundation defects due to differential settlement, slides, slope instability, uplift pressures, and
foundation seepage can also cause dam failure. These account for 30 percent of all dam failures.
• Failure due to piping and seepage accounts for 20 percent of all failures. These are caused by internal
erosion due to piping and seepage, erosion along hydraulic structures such as spillways, erosion due to
animal burrows, and cracks in the dam structure.
• Failure due to problems with conduits and valves, typically caused by the piping of embankment
material into conduits through joints or cracks, constitutes 10 percent of all failures.
Regulatory Oversight for Dams
National Dam Safety Act
Potential for catastrophic flooding due to dam failures led to passage of the National Dam Safety Act (Public
Law 92-367). The National Dam Safety Program requires a periodic engineering analysis of the majority of
dams in the country; exceptions include the following:
• Dams under jurisdiction of the Bureau of Reclamation, Tennessee Valley Authority, or International
Boundary and Water Commission
• Dams constructed pursuant to licenses issued under the Federal Power Act
• Dams that the Secretary of the Army determines do not pose any threat to human life or property.
The goal of this FEMA-monitored effort is to identify and mitigate the risk of dam failure so as to protect lives
and property. The National Dam Safety Program is a partnership among states, federal agencies, and other
stakeholders that encourages individual and community responsibility for dam safety. Under FEMA’s
leadership, state assistance funds have allowed all participating states to improve their programs through
increased inspections, emergency action planning, and purchases of needed equipment. FEMA has also
expanded existing and initiated new training programs. Grant assistance from FEMA provides support for
improvement of dam safety programs that regulate most of the dams in the United States.
Texas State Dam Safety Program
The Texas Commission on Environmental Quality Dam Safety Program monitors and regulates private and
public dams in Texas. The program periodically inspects dams that pose a high or significant hazard and makes
recommendations and reports to dam owners to help them maintain safe facilities. This program is governed by
Texas Administrative Code Title 30, Part 1, Chapter 299: Dams and Reservoirs.
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Effective September 1, 2013, dams are exempt from safety requirements if they meet all of the following criteria:
• Are located on private property
• Have a maximum impoundment capacity of less than 500 acre-feet
• Are classified as low or significant hazard
• Are located in a county with a population of less than 350,000 (per the 2010 census)
• Are not located within the corporate limits of a municipality.
Owners of exempt dams still have to comply with maintenance and operation requirements. There is no
exemption expiration date. Figure 4-6 shows the counties covered by the population exemption. Galveston
County is an exempt county.
Figure 4-6 Counties Exempt from the Texas Dam Safety Program
U.S. Army Corps of Engineers Dam Safety Program
The U.S. Army Corps of Engineers (USACE) operates and maintains approximately 700 dams nationwide. It is
also responsible for safety inspections of some federal and non-federal dams in the United States that meet the
size and storage limitations specified in the National Dam Safety Act. The Corps has inventoried dams; surveyed
each state and federal agency’s capabilities, practices and regulations regarding design, construction, operation,
and maintenance of the dams; and developed guidelines for inspection and evaluation of dam safety. The Corps
maintains the National Inventory of Dams, which contains information about a dam’s location, size, purpose,
type, last inspection and regulatory status (U.S. Army Corps of Engineers n.d.).
Federal Energy Regulatory Commission Dam Safety Program
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2022 Update
The Federal Energy Regulatory Commission (FERC) cooperates with a large number of federal and state
agencies to ensure and promote dam safety. More than 3,000 dams are part of regulated hydroelectric projects
in the FERC program. Two-thirds of these are more than 50 years old. As dams age, concern about their safety
and integrity grows, so oversight and regular inspection are important.
FERC inspects hydroelectric projects on an unscheduled basis to investigate the following:
• Potential dam safety problems
• Complaints about constructing and operating a project
• Safety concerns related to natural disasters
• Issues concerning compliance with the terms and conditions of a license.
Every five years, an independent engineer approved by the FERC must inspect and evaluate projects with dams
higher than 32.8 feet (10 meters), or with a total storage capacity of more than 2,000 acre-feet.
FERC monitors seismic research and applies it in performing structural analyses of hydroelectric projects. FERC
also evaluates the effects of potential and actual large floods on the safety of dams. During and following floods,
FERC visits dams and licensed projects, determines the extent of damage, if any, and directs any necessary
studies or remedial measures the licensee must undertake. The FERC publication Engineering Guidelines for
the Evaluation of Hydropower Projects guides the FERC engineering staff and licensees in evaluating dam
safety. The publication is frequently revised to reflect current information and methodologies.
FERC requires licensees to prepare emergency action plans and conducts training sessions on how to develop
and test these plans. The plans outline an early warning system if there is an actual or potential sudden release
of water from a dam due to failure. The plans include operational procedures that may be used, such as reducing
reservoir levels and reducing downstream flows, as well as procedures for notifying affected residents and
agencies responsible for emergency management. These plans are frequently updated and tested to ensure that
everyone knows what to do in emergency situations.
Levees
Levees have been constructed in the State of Texas for over 100 years to protect farms, ranch land, and populated
areas from flooding (State of Texas Hazard Mitigation Plan 2018). A levee is a physical barrier constructed to
protect areas from rising floodwaters. Levees typically remove valuable floodplain storage and block the ability
of the channel to move water. There are also concerns with rainfall that falls on the levee itself. Most important
is the possibility for catastrophic and sudden failure under extreme flood events, potentially resulting in loss of
life and total destruction of property.
A levee breach occurs when part of a levee gives way, creating an opening through which floodwaters may pass.
A breach may occur gradually or suddenly. The most dangerous breaches happen quickly during periods of high
water. Earthen levees can be damaged in several ways. Strong river currents and waves can erode the surface.
Trees growing on a levee can blow over, leaving a hole where the root wad and soil used to be. Burrowing
animals can create holes that enable water to pass through a levee. If severe enough, any of these situations can
lead to a zone of weakness that could cause a levee breach. In seismically active areas, earthquakes and ground
shaking can cause a loss of soil strength, weakening a levee and possibly resulting in failure. Seismic activity
can also cause levees to slide or slump, both of which can lead to failure.
The resulting torrent from a levee breach can quickly swamp a large area behind the failed levee with little or no
warning. When a levee system fails or is overtopped, severe flood damage can occur due to increased water
surface elevation associated with levees and the resulting increase in water velocity.
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Regulatory Oversight for Levees
U.S. Army Corps of Engineers and FEMA Levee Oversight
USACE and FEMA have differing roles and responsibilities related to levees. USACE addresses a range of
operation and maintenance, risk communication, risk management, and risk reduction issues as part of its
responsibilities under the Levee Safety Program. FEMA addresses mapping and floodplain management issues
related to levees, and it accredits levees as meeting requirements set forth by the National Flood Insurance
Program.
Depending on the levee system, USACE and FEMA may be involved with the levee sponsor and community
independently or—when a levee system overlaps both agency programs—jointly. Under both scenarios, the
long-term goals are similar: to reduce risk and lessen the devastating consequences of flooding. Some USACE
and FEMA partnering activities related to levees include:
• Joint meetings with levee sponsors and other stakeholders
• Integration of levee information into the National Levee Database
• State Silver Jackets teams
• Sharing of levee information
• Targeted task forces to improve program alignment
The Silver Jackets is a program that provides an opportunity to consistently bring together multiple state, federal,
tribal, and local agencies to learn from each other and apply their knowledge to reduce risk. The Program’s
primary goals include the following:
• Create or supplement a mechanism to collaboratively identify, prioritize, and address risk management
issues and implement solutions.
• Increase and improve risk communication through a unified interagency effort.
• Leverage information and resources and provide access to such national programs as FEMA’s Risk
MAP and USACE’s Levee Inventory and Assessment Initiative.
• Provide focused, coordinated hazard mitigation assistance in implementing high-priority actions such
as those identified by state hazard mitigation plans.
• Identify gaps among agency programs and/or barriers to implementation, such as conflicting agency
policies or authorities, and provide recommendations for addressing these issues.
The State of Texas has a Silver Jackets team. Their vision is to increase efficiency and coordination between
the state and federal governments in developing comprehensive and sustainable solutions to flood risk
management in the State of Texas. The team provides a variety of projects, plans, and outreach to help the State
mitigate and prevent future floods. Information about the team can be found online:
https://silverjackets.nfrmp.us/State-Teams/Texas
Coordination between USACE and FEMA with regard to levees is now standard within many of each agency’s
policies and practices. Over the past several years, both agencies coordinated policies where appropriate; jointly
participated in meetings with stakeholders; and participated in many multiagency efforts, such as the National
Committee on Levee Safety, the Federal Interagency Floodplain Management Task Force, and the Silver Jackets
Program.
National Committee on Levee Safety
The National Committee on Levee Safety was created by Congress to “develop recommendations for a national
levee safety program, including a strategic plan for implementation of the program.” The Committee adopted
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the vision of “an involved public and reliable levee system working as part of an integrated approach to protect
people and property from floods,” and has been working toward this goal since October 2008 (National
Committee on Levee Safety 2010). The Committee is made up of representatives from state, regional, and local
agencies; the private sector; USACE; and FEMA.
Maintenance Requirements
No levee provides protection from events for which it was not designed, and levees require maintenance to
continue to provide the level of protection they were designed and built to offer. Maintenance responsibility
belongs to a variety of entities including local, state, and federal government and private landowners. Well-
maintained levees may obtain certification through independent inspections.
Levees may not be certified for maintaining flood protection when the levee owner does not maintain the levee
or pay for an independent inspection. The impacts of an un-certified levee include higher risk of levee failure.
In addition, insurance rates may increase because FEMA identifies on Flood Insurance Rate Maps that the
structures are not certified to protect from a 1-percent annual chance flood event.
Location
Dam
According to the National Inventory of Dams, there are two dams in Galveston County.
• Galveston County Water Industrial Reservoir Dam - located at Dickinson Bayou in Texas City. This
dam, operated and maintained by the Gulf Coast Water Authority, is classified as a “High” hazard dam.
Although Texas City is not part of this plan, the neighboring jurisdictions of Clear Lake Shores, Kemah,
La Marque, and unincorporated areas of Galveston County could be impacted should this dam
experience a breach (Figure 4-7). Inundation mapping is not currently available for the dam, but a
Countywide action has been included in this plan to pursue obtaining inundation area data.
• GCWA Off Channel Term Stop Res Levee – privately owned, earthen dam with a heigh of 8 feet and a
storage area of 90 acre feet.
• Participating jurisdictions that could be impacted by the high hazard dam have mitigation actions to
address the hazard in their annexes, including Galveston County, Clear Lake Shores, Kemah, and La
Marque.
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Figure 4-7. Galveston County Water Industrial Reservoir Dam Area
Source: Galveston County HMP 2017
Figure 4-8. Dams Located in Galveston County, TX
Source: USACE 2022
Note: The green squares indicate the location of a dam.
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Levee
There are six levee systems located in Galveston County. The largest is the Galveston County hurricane flood
protection levee protects the cities of Texas City and La Marque. The levee is comprised of 15.7 miles of an
earthen berm and 1.3 miles of concrete wall, offering a total of 17 miles of protection. Hurricane flood protection
efforts in the Texas City area began in 1928 when some 13,500 feet of earthen levees were constructed by
Galveston County in the general area of the port and industrial section of Texas City. These levees reached an
elevation of about 14.5 feet. In 1932, construction began on an additional 8,300-foot-long concrete wall and a
3,800-foot-long earthen levee. Both of these structures were built to an elevation of 12.5 feet. The Texas City/La
Marque Hurricane Flood Protection Levee has numerous appurtenant structures. The project is designed to
provide protection for about 36 square miles of residential and industrial development from tropical hurricanes
of magnitudes up to and including a Standard Project Hurricane Tide of 15 feet (Galveston County 2017).
Figure 4-9. Levees Located in Galveston County, TX
Source: USACE 2022
SECTION 4.3.2: Dam and Levee Failure
Galveston County, TX | Hazard Mitigation Plan 4-33
2022 Update
Extent
Dam Failure
The extent or magnitude of a dam failure event can be measured in terms of the classification of the dam.
Additionally, there are two factors that influence the potential severity of a full or partial dam failure are: (1) the
amount of water impounded; and (2) the density, type, and value of development and infrastructure located
downstream (Association of State Dam Safety Officials 2020). The following classification system is used by
the USACE for the hazard potential of dams.
• Low Hazard Potential Dams are dams where failure or mis-operation results in no probable loss of
human life and low economic and/or environmental losses. Losses are principally limited to the owner’s
property.
• Significant Hazard Potential Dams where failure or mis-operation results in no probable loss of
human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or can
impact other concerns. Significant hazard potential classification dams are often located in
predominantly rural or agricultural areas but could be located in areas with population and significant
infrastructure.
• High Hazard Potential Dams are dams where failure or mis-operation will probably cause loss of
human life.
Levee Failure
In the event of a levee failure, floodwaters may ultimately inundate the protected area landward of the levee.
The extent of inundation is dependent on the flooding intensity. Failure of a levee during a 1 percent annual
chance flood will inundate the approximate 100-year flood plain previously protected by the levee. Residential
and commercial buildings located nearest the levee overtopping or breach location will suffer the most damage
from the initial embankment failure flood wave. Landward buildings will be damaged by inundation (FEMA
2004).
Levees require maintenance to continue to provide the level of protection they were designed and built to offer.
Maintenance responsibility belongs to a variety of entities including local, state, and federal government and
private landowners. Well-maintained levees may obtain certification through independent inspections. Levees
may not be certified for maintaining flood protection when the levee owner does not maintain the levee or pay
for an independent inspection. The impacts of an uncertified levee include higher risk of levee failure. In
addition, insurance rates may increase because FEMA identifies on Flood Insurance Rate Maps that the
structures are not certified to protect from a 1-percent annual chance flood event (FEMA 2004).
Worst-Case Scenario
While the probability of a dam or levee failure is low, a worst-case scenario would be a hurricane or tropical
storm that would stall over the County, causing the dam or levee to breech or overtop, impacting areas that are
supposed to be protected. If a dam or levee failure were to occur, properties protected by the structure could see
up to four feet of standing water. Injuries may occur, but loss of life is not expected.
Previous Occurrences and Losses
According to available records from the State of Texas 2018 HMP Update, Galveston County Multi-
Jurisdictional HMP, and the National Performance of Dams Program, there have been no reported dam or levee
incidents recorded for Galveston County.
SECTION 4.3.2: Dam and Levee Failure
Galveston County, TX | Hazard Mitigation Plan 4-34
2022 Update
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016).
An increasing average annual temperature will directly impact the atmospheric moisture potential. The
probability of expanding atmospheric moisture leads to an increasing amount of rainfall during storm events.
The increased potential volume of rainfall will directly lead to an increasing pressure placed on levee systems
during future riverine flood events (State of Texas Hazard Mitigation Plan 2018).
Probability of Future Occurrences
All dams face a “residual risk” of failure, which represents the risk that conditions may exceed those for which
the dam was designed. For example, dams may be designed to withstand a probable maximum precipitation,
defined as “theoretically, the greatest depth of precipitation for a given duration that is physically possible over
a given storm area at a particular geographical location at a certain time of the year”. The chance of occurrence
of a precipitation event of a greater magnitude than that represents residual risk for such dams. This in tu rn
represents a theoretical probability of future occurrence for a dam failure event, though the probability of an
event exceeding the assumed maximum is not generally calculated as part of dam design.
Levee failure probabilities are considered to be higher than dam failure probabilities because levees are often
exposed to more adverse conditions associated with high velocity flood flows, such as erosion and scour. Many
levees are designed to overtop in high flow conditions; such overtopping is referred to as design failure.
No historical events of dam or levee failures have been recorded in the County, though the risk of failure s is
monitored. Based on the lack of historical occurrences, the probability of a future event is considered low (not
likely to occur in 100 years). Refer to Section 4.4 for additional information on the hazard ranking methodology
and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entire City of Texas City and La Marque are vulnerable to the levee failure hazard; and the jurisdictions of Clear
Lake Shores, Kemah, La Marque, and unincorporated areas of Galveston County are vulnerable to the dam
failure hazard. The following text evaluates and estimates the potential impact of the dam and levee failure
hazard in the County as a whole.
Impact on Life, Health and Safety
The impact of dam and levee failure on life, health, and safety is dependent on several factors such as the class
of dam/levee, the area that the dam/levee is protecting, the location of the dam/levee, and the proximity of
structures, infrastructure, and critical facilities to the dam or levee structure. The level of impact that a failure
could have can be predicted based upon the hazard potential classification as rated by the USACE.
Table 4-10. USACE Hazard Potential Classifications for Dams
Hazard
Category (a) Direct Loss of Life (b) Lifeline Losses (c) Property Losses (d)
Environmental
Losses (e)
Low None (rural location, no
permanent structures for
human habitation)
No disruption of
services (cosmetic or
rapidly repairable
damage)
Private agricultural
lands, equipment, and
isolated buildings
Minimal incremental
damage
SECTION 4.3.2: Dam and Levee Failure
Galveston County, TX | Hazard Mitigation Plan 4-35
2022 Update
Hazard
Category (a) Direct Loss of Life (b) Lifeline Losses (c) Property Losses (d)
Environmental
Losses (e)
Significant Rural location, only transient
or day-use facilities
Disruption of essential
facilities and access
Major public and
private facilities
Major mitigation
required
High Certain (one or more)
extensive residential,
commercial, or industrial
development
Disruption of essential
facilities and access
Extensive public and
private facilities
Extensive mitigation
cost or impossible to
mitigate
Source: FEMA 2004
Note:
a. Categories are assigned to overall projects, not individual structures at a project.
b. Loss-of-life potential is based on inundation mapping of area downstream of the project. Analyses of loss-of-life potential should
consider the population at risk, time of flood wave travel, and warning time.
c. Lifeline losses include indirect threats to life caused by the interruption of lifeline services from project failure or operational
disruption; for example, loss of critical medical facilities or access to them.
d. Property losses include damage to project facilities and downstream property and indirect impact from loss of project services, such
as impact from loss of a dam and navigation pool, or impact from loss of water or power supply.
e. Environmental impact downstream caused by the incremental flood wave produced by the project failure, beyond what would
normally be expected for the magnitude flood event under which the failure occurs.
Levee failure impacts depend on several factors including severity of the event and whether or not adequate
warning time is provided to residents. The population living in or near the inundation areas are considered
exposed to the hazard. However, exposure should not be limited only to those who reside within a defined
hazard zone, but everyone who may be affected by a hazard event (e.g., people are at risk while traveling in
flooded areas, or their access to emergency services is compromised during an event); the degree of that impact
varies and is not strictly measurable.
Vulnerable populations are all populations downstream from levee failures that are incapable of escaping the
area within the allowable time frame. This population includes the elderly, young and individuals with
disabilities, access or functional needs who may be unable to get themselves out of the inundation area. The
vulnerable population also includes individuals who would not have adequate warning from the emergency
warning system (e.g., television or radio); this would include residents and visitors. The population adversely
affected by a levee failure may also include those beyond the disaster area that rely on the dam for providing
potable water.
Floods created from a levee failure and their aftermath present numerous threats to public health and safety
including exposure to unsafe food, contaminated drinking and washing water, mosquitoes, animals, mold, and
mildew. For more detailed descriptions of these and additional threats to public health and safety, refer to Section
4.3.6 (Flood). Current loss estimation models such as Hazus are not equipped to measure public health impacts
such as these. The best preparation for these effects includes awareness that they can occur, education of the
public on prevention, and planning to deal with them during responses to dam or levee failure events.
Impact on General Building Stock
Vulnerable properties are those closest to the dam or levee area. These properties would experience the largest,
most destructive surge of water. Transportation routes are vulnerable to dam inundation and have the potential
to be wiped out, creating isolation issues. This includes all roads, railroads, and bridges in the path of the dam
inundation. Those that are most vulnerable are those that are already in poor condition and would not be able to
withstand a large water surge. Utilities such as overhead power lines, cable and phone lines could also be
vulnerable. Loss of these utilities could create additional isolation issues for the inundation areas.
Impact on Critical Facilities and Lifelines
Transportation routes are vulnerable to dam inundation and have the potential to be wiped out, creating isolation
issues and significant disruption to travel, including all roads, railroads, and bridges in areas in and around the
SECTION 4.3.2: Dam and Levee Failure
Galveston County, TX | Hazard Mitigation Plan 4-36
2022 Update
levee. Those that are most vulnerable are those that are already in poor condition and would not be able to
withstand a large water surge. Utilities such as overhead power lines, cable and phone lines in the inundation
zone could also be vulnerable. If phone lines were lost, significant communication issues may occur in the
planning area due to limited cell phone reception in many areas. In addition, emergency response would be
hindered due to the loss of transportation routes as well as some protective-function facilities located in the
inundation zone. Recovery time to restore many critical functions after an event may be lengthy, as wastewater,
potable water, and other community facilities are located in the dam inundation zone.
Impact on the Economy
Severe flooding that follows an event like a dam failure can cause extensive structural damage and withhold
essential services. The cost to recover from flood damages after a surge will vary depending on the hazard risk
of each dam. Severe flooding that follows an event like a dam failure can cause extensive damage to public
utilities and disruptions to delivery of services. Loss of power and communications may occur and drinking
water and wastewater treatment facilities can become temporarily out of operation. Debris from surrounding
buildings can accumulate should the dam mimic major flood events, such as the 1-percent annual chance flood
event that is discussed in Section 4.3.6 (Flood).
Levee failure events can significantly impact the local and regional economy. Similar to flooding, losses include,
but are not limited to, damages to buildings and infrastructure, agricultural losses, business interruption and
impacts on tax base. Flooding as a result of levee failure can cause extensive damage to public utilities and
disruptions in delivery of services. Loss of power and communications may occur and drinking water and
wastewater treatment facilities may be temporarily out of operation.
Impact on the Environment
The environmental impacts of a dam or levee failure can include significant water-quality and debris-disposal
issues or severe erosion that can impact local ecosystems. Flood waters can back up sanitary sewer systems and
inundate wastewater treatment plants, causing raw sewage to contaminate residential and commercial buildings
and the flooded waterway. The contents of unsecured containers of oil, fertilizers, pesticides, and other
chemicals may get added to flood waters. Hazardous materials may be released and distributed widely across
the floodplain. Water supply and wastewater treatment facilities could be offline for weeks. After the flood
waters subside, contaminated and flood-damaged building materials and contents must be properly disposed of.
Contaminated sediment must be removed from buildings, yards, and properties.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change
Projected Development
Any areas of growth in Texas City, La Marque, Clear Lake Shores, Kemah, and unincorporated areas of
Galveston County could be potentially impacted by the dam and levee failure hazard because these areas are
exposed and vulnerable. Areas in and around the levees are the most vulnerable to losses; therefore, any
development in these areas will be more susceptible to levee failure impacts.
SECTION 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-37
2022 Update
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2019 American Community Survey estimated population of 350,682. The population of the county is expected
to increase over the next few years. The increase in population will expose more people to the dam and levee
failure hazard.
Climate Change
An increasing average annual temperature will directly impact the atmospheric moisture potential. The
probability of expanding atmospheric moisture leads to an increasing amount of rainfall during storm events.
The increased potential volume of rainfall will directly lead to an increasing pressure placed on levee systems
during future riverine flood events (State of Texas HMP 2018).
Change of Vulnerability Since the 2017 HMP
Overall, the County’s vulnerability has not changed, and the County will continue to be exposed and vulnerable
to dam and levee failure events, especially those located within or near downstream inundation zones. Because
of the sensitive nature of the dam failure inundation zones, potential losses have not been quantified and
presented in this plan. To estimate potential losses to population, buildings, critical facilities and infrastructure,
inundation areas and depths of flooding may be used to generate depth grids. Hazus may be used to estimate
potential losses for the County and participating municipalities in future HMP updates.
4.3.3 Drought
This section provides a hazard profile and vulnerability assessment of the drought hazard for Galveston County.
Hazard Profile
This section presents information regarding the description, extent, location, previous occurrences and losses,
climate change projections and probability of future occurrences for the drought hazard.
Description
Drought is defined as the consequence of a natural
reduction in the amount of precipitation expected over
an extended period of time, usually a season or more
in length (State of Texas Hazard Mitigation Plan
2018). Drought conditions occur in virtually all
climatic zones. Drought characteristics vary
significantly from one region to another and are
relative to the normal precipitation in that region.
Drought can increase wildfire/brush fire risk and can
affect agriculture, water supply, aquatic ecology,
wildlife, and plant life. There are five classifications
of drought, as presented in the figure to the right.
Location
A drought occurs on a regional scale; therefore, all of Galveston County is vulnerable and at risk. Droughts can
occur at any time and have the potential to impact every person directly or indirectly in the County, as well as
the local economy.
Source: University of Nevada Cooperative Extension,
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-38
2022 Update
Extent
The severity of a drought depends on the degree of moisture deficiency, the duration of the event, and the size
and location of the affected area. The longer the duration of the drought and the larger the area impacted, the
more severe the potential impacts (University of Nevada, Reno Extension College of Agriculture, Biotechnology
& Natural Resources n.d.), Galveston County has the potential to experience the entire range of effects, from
extreme drought to extremely moist conditions, as described in the Palmer Drought Severity Index (PDSI).
U.S. Drought Monitor
The U.S. Drought Monitor (USDM) is a map that shows the location and intensity of drought across the United
States. The data is updated every. The USDM uses a five-category system, labeled Abnormally Dry or D0, (a
precursor to drought, not actually drought), and Moderate (D1), Severe (D2), Extreme (D3) and Exceptional
(D4) Drought. Drought categories show experts' assessments of conditions related to dryness and drought
including observations of how much water is available in streams, lakes, and soils compared to usual for the
same time of year. Figure 4-11 shows the USDM for November 23, 2021. The figure is shows that Galveston
County had no drought condition for the week of November 23, 2021.
Figure 4-10 U.S. Drought Monitor for Texas, November 23, 2021
Note: The green circle represents the approximate location of Galveston County
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-39
2022 Update
Figure 4-11. U.S. Drought Monitor for November 23, 2021
Palmer Drought Severity Index
The Palmer Drought Severity Index (PDSI) is primarily based on soil conditions. Soil with decreased moisture
content is the first indicator of an overall moisture deficit. Table 4-11 lists the PDSI classifications. At the one
end of the spectrum, 0 is used as normal and drought is indicated by negative numbers. For example, -2 is
moderate drought, -3 is severe drought, and -4 is extreme drought. The PDSI can reflect excess precipitation
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-40
2022 Update
using positive numbers; however, this is not shown in Table 4-11. The PDSI is commonly converted to the
Palmer Drought Category (U.S. Drought Monitor n.d.).
Table 4-11. Palmer Drought Category and Palmer Drought Index Descriptions
Category Description Possible Impacts (for Texas)
Palmer
Drought Index
D0 Abnormally
Dry
• Producers begin supplemental feeding for livestock
• Planting is postponed; forage germination is stunted; hay cutting is reduced
• Grass fires increase
• Surface water levels decline
-1.0 to -1.9
D1 Moderate
Drought
• Dryland crops are stunted
• Early cattle sales begin
• Wildfire frequency increases
• Stock tanks, creeks, streams are low; voluntary water restrictions are requested
-2.0 to -2.9
D2 Severe
Drought
• Pasture conditions are very poor
• Soil is hard, hindering planting; crop yields decrease
• Wildfire danger is severe; burn bans are implemented
• Wildlife moves into populated areas
• Hydroelectric power is compromised; well water use increases; mandatory water
restrictions are implemented
-3.0 to -3.9
D3 Extreme
Drought
• Soil has large cracks; soil moisture is very low; dust and sandstorms occur
• Row and forage crops fail to germinate; decreased yields for irrigated crops and
very large yield reduction for dryland crops are reported
• Need for supplemental feed, nutrients, protein, and water for livestock increases;
herds are sold
• Increased risk of large wildfires is noted
• Many sectors experience financial burden
• Severe fish, plant, and wildlife loss reported
• Water sanitation is a concern; reservoir levels drop significantly; surface water is
nearly dry; river flow is very low; salinity increases in bays and estuaries
-4.0 to -4.9
D4 Exceptional
Drought
• Exceptional and widespread crop loss is reported; rangeland is dead; producers
are not planting fields
• Culling continues; producers wean calves early and liquidate herds due to
importation of hay and water expenses
• Seafood, forestry, tourism, and agriculture sectors report significant financial loss
• Extreme sensitivity to fire danger; firework restrictions are implemented
• Widespread tree mortality is reported; most wildlife species’ health and
population are suffering
• Devastating algae blooms occur; water quality is very poor
• Exceptional water shortages are noted across surface water sources; water table is
declining
• Boat ramps are closed; obstacles are exposed in water bodies; water levels are at
or near historic lows
-5.0 or less
Source: U.S. Drought Monitor 2021
Keetch-Byram Drought Index (KBDI)
The KBDI is an index used to determining forest fire potential. The drought index is based on a daily water
balance, where a drought factor is balanced with precipitation and soil moisture (assumed to have a maximum
storage capacity of eight-inches) and is expressed in hundredths of an inch of soil moisture depletion. The index
ranges from 0 to 800, where a drought index of 0 represents no moisture depletion, while an index of 800
represents absolutely dry conditions (USFS - Wildland Fire Assessment System n.d.)
Table 4-12. KBDI Index
KBDI Value Description
0 to 200 Soil moisture and large class fuel moistures are high and do not contribute much to fire
intensity. Typical of spring dormant season following winter precipitation
200 to 400 Typical of late spring, early growing season. Lower litter and duff layers are drying and
beginning to contribute to fire intensity
400 to 600 Typical of late summer, early fall. Lower litter and duff layers actively contribute to
fire intensity and will burn actively.
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-41
2022 Update
KBDI Value Description
600 to 800
Often associated with more severe drought with increased wildfire occurrence. Intense,
deep burning fires with significant downwind spotting can be expected. Live fuels can
also be expected to burn actively at these levels.
This index is currently derived from ground based estimates of temperature and precipitation resulting from
weather stations and interpolated manually by experts at the Texas Forest Service (TFS) for counties across the
State. Figure 4-12 shows the KBDI for the State of Texas for November 28, 2021. The figure shows KBDI
value of 0-500 for the County.
Figure 4-12. KBDI for the State of Texas, November 26, 2021
Worst-Case Scenario
A multi-year drought with a Palmer Drought Category of D4 that impacts the southeastern portion of Texas, like
the 2008 to 2011 drought, is the worst-case scenario for the County. If another severe drought occurs before
these systems have a chance to recover, it could exacerbate the stress already placed on existing planning area
water resources. Severe droughts can also lead to crop and livestock losses, impacting the food supply and
economy.
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-42
2022 Update
Previous Occurrences and Losses
Between 1954 and 2021, Federal Emergency Management Agency (FEMA) declared that Texas experienced 46
drought-related major disaster (DR) or emergency (EM). Generally, drought-related disasters affect a wide
region of the state and can impact many counties; however, Galveston County was not included in the disaster
declarations.
The U.S. Department of Agriculture (USDA) keeps records of agricultural disaste rs. Between 2012 and
November 2021, Galveston County was included seven declarations related to drought.
Table 4-13. USDA Drought Disaster Declarations for Galveston County, TX between 2012 and 2021
Designation
Number Incident Date(s) Approval Date Description of Disaster Crop Disaster Year
S3288 Starting January 1, 2012 July 12, 2012 Drought, Wind, Fire, Heat 2012
S3500 Starting February 5, 2013 April 3, 2013 Drought, Wind, Fire, Heat,
Insects
2013
S3507 Starting April 2, 2013 April 10, 2013 Drought, Wind, Fire, Heat,
Insects
2013
S3555 Starting July 9, 2013 July 17, 2013 Drought, Wind, Fire, Heat,
Insects
2013
S3681 April 1 – October 31, 2013 April 23, 2014 Drought, Wind, Fire, Heat 2013
S4669 Starting February 18, 2020 May 6, 2020 Drought 2020
S4932 Starting February 2, 2021 March 26, 2021 Drought 2021
Source: USDA Farm Service Agency 2021
Climate Change Projections
Climate is defined not simply as average temperature and precipitation but also by the type, frequency, and
intensity of weather events. Both globally and at the local scale, climate change has the potential to alter the
prevalence and severity of extremes such as droughts. While predicting changes of drought events under a
changing climate is difficult, understanding vulnerabilities to potential changes is a critical part of estimating
future climate change impacts on human health, society and the environment (EPA 2016).
Wither a warmer climate, droughts can become more frequent, more severe, and longer lasting. According to
the National Climate Assessment, variable precipitation and rising temperatures are intensifying droughts,
increasing heavy downpours, reducing snowpack, and causing declines in water survey quality. Future warming
will add to the stress on water supplies and impact the availability of water supply (USGCRP 2018)
Probability of Future Occurrences
The frequency of droughts is difficult to forecast as drought occurrences are cyclical in nature and will occur in
the future. Based on national annual data from 1895 to 1995, Galveston County underwent severe or extreme
conditions approximately 5 to 9.9% of the time (illustrated in Figure 4-13).
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-43
2022 Update
Figure 4-13. Palmer Drought Severity Index (1895 to 1995)
Source: National Drought Mitigation Center 2020
For the 2022 HMP update, the most up-to-date data was collected to calculate the probability of future occurrence
of drought events, of all magnitudes, for Galveston County. Information from NOAA-NCEI storm events
database, the 2018 State of Texas HMP, the 2017 Galveston County HMP, and the Drought Impact Report were
used to identify the number of drought events that occurred between 1950 and 2021. Using these sources ensures
the most accurate probability estimates possible. Table 4-14 presents the probability of future occurrence of
drought events in Galveston County.
Table 4-14. Probability of Future Drought Events in Galveston County
Hazard Type
Number of Occurrences Between 1950
and 2021
Percent chance of occurrence in any
given year
Drought 13 18.06%
Sources: NOAA NCEI 2021, State of Texas 2018, Galveston County 2017
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected drought events
since 1968. Due to limitations in data, not all drought events occurring between 1954 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated
Based on the 13 recorded drought events over 71 years, Galveston County averages less than one drought a year.
A drought event has an 18.06% chance of occurring in any given year in the County. Based on the history of
events and input from the Steering Committee, the probability for drought occurring in the County is considered
occasional (between 10 and 100% annual chance of occurring). Refer to Section 4.4 for additional information
on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entire County is exposed to the drought hazard; therefore, all assets within the County (population, structures,
Section 4.3.3: Drought
Galveston County, TX | Hazard Mitigation Plan 4-44
2022 Update
critical facilities, and lifelines), as described in Section 3 (County Profile), are potentially vulnerable to a drought
event. The following text evaluates and estimates the potential impact of the drought hazard in the County.
Impact on Life, Health, and Safety
The entire population of Galveston County is vulnerable to drought events (2019 American Community Survey
5-Year Estimate: 342,139 people). Drought conditions can affect public health and safety, including reduced
local firefighting capabilities, health problems related to low water flows and poor water quality, and health
problems related to dust. If droughts are severe enough, these health problems can lead to loss of human life.
Other possible impacts include recreational risks; effects on air quality; diminished living conditions related to
energy, air quality, and sanitation and hygiene; compromised food and nutrition; and increased incidence of
illness and disease. Due to their age, health conditions, and limited ability to mobilize to shelters, cooling, and
medical resources, the infirm, young, and elderly are particularly susceptible to drought and extreme
temperatures, sometimes associated with drought conditions. Some drought-related health effects are short term,
while others can be long term (CDC 2012).
Impact on General Building Stock
No structures will be directly affected by drought conditions, though some structures may become vulnerable to
wildfires, which are more likely following years of drought. Droughts can have significant impacts on other
types of property such as landscaped areas and economically important natural resources.
Impact on Critical Facilities and Lifelines
Water supply facilities may be affected by drought events. However, a majority of the critical facilities defined
for this plan will continue to be operational during a drought.
Impact on the Economy
Drought causes the most significant economic impacts on industries that use water or depend on water for their
business, most notably agriculture and related sectors, power plants, and oil refineries. In addition to losses in
yields in crop and livestock production, drought is associated with increased insect infestations, plant diseases,
and wind erosion. Drought can lead to other losses because so many sectors are affected—losses that include
reduced income for farmers and reduced business for retailers and others who provide goods and services to
farmers. This leads to unemployment, increased credit risk for financial institutions, capital shortfalls, and loss
of tax revenue. Prices for food, energy, and other products may also increase as supplies decrease.
According to the 2017 Census of Agriculture, Galveston County has 73,125 acres of farmland, resulting in a
$9.2 billion market value of products sold. According to the 2018 State of Texas HMP, between 1996 and 2016,
the County experienced drought-related losses (property plus crop losses) ranging between $143 million and
$3.1 billion (State of Texas HMP 2018).
Future Changes that May Impact Vulnerability
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-45
2022 Update
Projected Development
Any areas of growth could be potentially impacted by the drought hazard because the entire County is exposed
and vulnerable to droughts. Future growth and development could impact the amount of potable water available
due to a drain on the available water resources. An increased drain on water resources would not only impact
the county’s population, but it would also exacerbate impacts to other areas of the county as discussed above,
including agriculture and recreational facilities.
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2019 American Community Survey population of 350,682. The population of the County is expected to increase
over the next few years. With an increase in population, the demand for water supply will increase. During a
drought, the amount of water needed might not be available. This might require reallocation of water resources
to meet demands during a drought. If needed, the County can pass special ordinances regulating the amount of
water consumed and used during periods of drought to conserve water.
Climate Change
Climate change as the potential to impact the number of and the severity of droughts. An increased incidence
of drought might impact availability of water supplies, primarily placing an increased stress on the population.
It is unlikely that structure exposure and vulnerability would increase as a direct result of drought, although
secondary impacts of drought, such as wildfire, could increase and threaten structures. If a wildfire were to occur
during a drought, emergency services might face complications from a water shortage depending on their water
source, and critical water-related service sectors might need to adjust management practices and actively manage
resources. Increased incidence of drought increases the potential for impacts on the local economy, including
the production of agricultural products.
Change of Vulnerability since the 2017 HMP
Since the 2017 HMP, Galveston County has grown in population and the economic value of its agricultural
sector. Therefore, the number of people and farms exposed to the hazard has increased. Overall, the County will
continue to be exposed and vulnerable to drought events.
4.3.4 Expansive Soils
The following section provides the hazard profile and vulnerability assessment for the expansive soils hazard in
Galveston County.
Hazard Profile
Description
Expansive soils are soils that expand when water is added and shrink when they dry out. This continuous change
in soil volume can cause structures to move unevenly and crack and roads and sidewalks to buckle. Soils with a
high clay content exhibit high expansive properties. Slab on grade construction is the most susceptible to damage
from expansive clays.
Location
Figure 4-14 provides the expansive soil ratings (in percent) as classified by the USGS. The low range, 0‐3
percent, represents fine sand with little moisture content and thus low linear extensibility. The high range, 9‐17
percent represents clay like soils and is found in areas of Galveston County, Friendswood, League City, and La
Marque. Bayou Vista, Clear Lake Shores, Hitchcock, Jamaica Beach, Kemah, Santa Fe, and Tiki Island are
located within the low to moderate areas (Galveston County 2017).
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-46
2022 Update
Figure 4-14 Expansive Soil Ratings
(Galveston County 2017)
Extent
Linear extensibility refers to the change in length of an unconfined clod as moisture content is decreased from a
moist to a dry state. It is an expression of the volume change as a percentage change for the soil. The amount
and type of clay minerals in the soil influence volume change. Figure 4-15 shows soil extensibility ratings in the
County. Soil extensibility ratings over 9 percent are considered to be very high. Areas along the Gulf have lower
linear extensibility rates in general. Inland soil extensibility rates vary greatly by location. For the high and very
high extensibility areas, the extent of damages may include cracking foundations, shifting and/or disruption of
underground utilities, and shifting of roadways.
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-47
2022 Update
Figure 4-15 Linear Extensibility of Galveston County Soils
Source: (USDA 2021)
Worst-Case Scenario
A season of flooding with rapid drying conditions such as in a drought would present a worst-case scenario for
the expansive soils hazard in areas with a soil extensibility rating over 9; however, since insufficient historical
records exist, it is not possible to use previous records to project details surrounding a worst-case scenario in the
future. Nevertheless, underground utility pipes, foundations, roadways, and sidewalks would be vulnerable to
cracking or buckling, causing damage to the built environment.
Previous Occurrences and Losses
There is insufficient data on losses from expansive soils in Galveston County, and there are no recorded previous
occurrences in the FEMA, NCEI, USGS, or USDA databases.
Climate Change Projections
Climate change is likely to have significant impacts on the performance of residential buildings constructed on
expansive soils. Precipitation and temperature are the primary weather parameters used for determining ground
movement (Sun, Li and Zhou 2017). The climate of Texas is changing. Most of the State has warmed between
one half and one degree Fahrenheit in the past century. In the eastern two-thirds of the State, average annual
rainfall is increasing; however, the soil is becoming drier. Rainstorms are more intense, and floods are becoming
more severe. In the coming decades, storms are likely to become more severe in Texas (EPA 2016).
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-48
2022 Update
Probability of Future Events
It is anticipated that expansive soils will continue to affect Galveston County. As the frequency of severe
weather and drought conditions continues to increase, the probability for future expansive soils changes will
likely increase as well. Due to the gradual nature of this hazard and the lack of data on individual expansive
soil events, the probability of future events is based on history of occurrences and input from the County. The
probability of occurrence for expansive soils affecting the planning area is considered high (100% chance
occurring; occurs multiple times a year).
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entire County is vulnerable, but Galveston County, Friendswood, League City, and La Marque, are especially
vulnerable. The following text evaluates and estimates the potential impact of the expansive soils hazard in the
County as a whole.
Impact on Life, Health and Safety
The population living in areas of high linear extensibility are considered especially vulnerable to the expansive
soils hazard. A quantitative analysis was conducted using expansive soil hazard areas to determine the population
living in expansive soils hazard areas. It was found that almost half of the population of Galveston County is
exposed to this hazard (Table 4-15). However, exposure should not be limited only to those who reside within a
defined hazard zone, but everyone who may be affected by a hazard event (e.g., people are at risk while traveling,
people inside of vulnerable buildings, or people whose access emergency services is compromised during an
event); the degree of that impact varies and is not strictly measurable.
Table 4-15. Population living in the expansive soils hazard area
Jurisdiction
Total Population
(American Community
Survey 2015-2019)
Estimated Population Located in the Expansive Soils
(Linear Extensibility >6%) Hazard Area
Number of People Percent of Total
Bayou Vista (C) 1,763 1,762 99.9%
Clear Lake Shores (C) 1,258 55 4.4%
Dickinson (C) 20,847 15,209 73.0%
Friendswood (C) 41,213 34,226 83.0%
Hitchcock (C) 7,301 6,006 82.3%
Jamaica Beach (C) 1,078 0 0.0%
Kemah (C) 1,807 526 29.1%
La Marque (C) 18,030 16,350 90.7%
League City (C) 114,392 49,884 43.6%
Santa Fe (C) 12,735 498 3.9%
Tiki Island (V) 1,106 0 0.0%
Galveston County (Total) 350,682 167,514 47.8%
Source: USDA/NRCS 2020 (Linear Extensibility >6%)
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on General Building Stock and Critical Facilities
Soils capable of changes in volume present a hazard to structures built over them and to the pipelines, sewer and
water lines buried in them. Houses and one‐story commercial buildings are more apt to be damaged by the
expansion of swelling clays than are multi‐story buildings, which are usually heavy enough to counter swelling
pressures. However, if constructed on wet clay, multi‐story buildings may also be damaged by clay shrinkage
when moisture levels are substantially reduced (State of Texas HMP 2018). Figure 4-16 illustrates where the
expansive soil hazard areas are located in Galveston County.
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-49
2022 Update
Figure 4-16. USDA/NRCS Expansive Soils Hazard Area – Galveston County
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-50
2022 Update
An estimated 40% of buildings in Galveston County are located in the expansive soils hazard area, with the most
vulnerable jurisdictions being Bayou Vista (99.9%), La Marque (89.6%), Friendswood (82.8%), and Hitchcock
(80.8%) (Table 4-16).
Table 4-16. Building Stock Located in the Expansive Soils Hazard Area
Jurisdiction
Total
Number of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located in the Expansive
Soils (Linear Extensibility >6%) Hazard Area
Number
of
Buildings
Percent
of Total
Total
Replacement
Cost Value of
Buildings
Percent
of Total
Bayou Vista (C) 1365 $445,354,087.33 1,364 99.9% $445,280,611 100.0%
Clear Lake Shores (C) 1155 $904,562,368.66 76 6.6% $204,737,419 22.6%
Dickinson (C) 10351 $6,601,710,645.63 7,483 72.3% $5,124,865,418 77.6%
Friendswood (C) 14891 $10,815,456,384.12 12,325 82.8% $8,583,015,518 79.4%
Hitchcock (C) 5452 $4,592,036,651.86 4,407 80.8% $3,495,801,680 76.1%
Jamaica Beach (C) 1291 $458,205,838.82 0 0.0% $0 0.0%
Kemah (C) 1634 $2,631,702,105.60 483 29.6% $967,274,297 36.8%
La Marque (C) 10749 $7,927,292,522.28 9,633 89.6% $6,799,665,275 85.8%
League City (C) 46742 $31,237,974,594.10 20,362 43.6% $13,886,431,057 44.5%
Santa Fe (C) 7942 $4,831,628,162.13 321 4.0% $152,788,092 3.2%
Tiki Island (V) 868 $365,209,145.44 0 0.0% $0 0.0%
Galveston County (Total) 209947 $166,321,604,688.46 85,766 40.9% $62,998,467,572 37.9%
Source: USDA/NRCS 2020 (Linear Extensibility >6%), Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
While all infrastructures in the higher-risk areas are vulnerable, slab-on-grade structures are most likely to suffer
damages from expansive soils. In addition, older structures built to less stringent building codes may be more
susceptible to damages than new construction. Bridges, highways, streets, and parking lots are especially
vulnerable when they are constructed when clays are dry, such as during a drought, and then subsequent soaking
rains swell the clay (State of Texas HMP 2018).
Impact on Critical Facilities and Lifelines
Expansive soil events may potentially impact critical facilities and lifelines identified within the County. Critical
services may not be available if critical facilities or lifelines are directly damaged or transportation routes to
access these critical facilities are breached due to expansive soil events.
Table 4-17. Critical Facilities and Lifelines Located in the Expansive Soils Hazard Area
Jurisdiction
Total CFs
Located in
Jurisdiction
Total Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline Facilities
Located in the Expansive Soils (Linear Extensibility
>6%) Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent of
Total Lifelines
Bayou Vista (C) 5 5 5 100.0% 5 100.0%
Clear Lake Shores (C) 24 24 6 25.0% 6 25.0%
Dickinson (C) 91 83 74 81.3% 68 81.9%
Friendswood (C) 96 82 83 86.5% 69 84.1%
Hitchcock (C) 214 212 104 48.6% 102 48.1%
Jamaica Beach (C) 11 11 0 0.0% 0 0.0%
Kemah (C) 15 14 11 73.3% 11 78.6%
La Marque (C) 121 107 83 68.6% 70 65.4%
Section 4.3.4: Expansive Soils
Galveston County, TX | Hazard Mitigation Plan 4-51
2022 Update
Jurisdiction
Total CFs
Located in
Jurisdiction
Total Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline Facilities
Located in the Expansive Soils (Linear Extensibility
>6%) Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent of
Total Lifelines
League City (C) 321 283 156 48.6% 138 48.8%
Santa Fe (C) 135 128 16 11.9% 16 12.5%
Tiki Island (V) 7 7 0 0.0% 0 0.0%
Galveston County (Total) 2,437 2,317 940 38.6% 874 37.7%
Source: USDA/NRCS 2020 (Linear Extensibility >6%), Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on the Economy
Expansive soil events can significantly impact the local and regional economy. Similar to erosion, losses include,
but are not limited to, damages to buildings and infrastructure, agricultural losses, business interruption, and
disruptions in delivery of service.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change
Projected Development
Any areas of growth in Friendswood, League City, and La Marque, could be potentially impacted by the
expansive soils hazard because these areas are especially vulnerable. Therefore, any development in these areas
will be more susceptible to expansive soil impacts.
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2019 American Community Survey estimated population of 350,682. Furthermore, the populations of the most
vulnerable jurisdictions have increased. The population of the county is expected to increase over the next few
years. The increase in population will expose more people to the expansive soils hazard.
Climate Change
Climate change has the potential to impact the number and severity of droughts. Furthermore, climate change is
predicted to increase temperatures, leading to an expansion in atmospheric moisture, resulting in an increased
amount of rainfall during storm events. The increasing severity of future droughts and rainfall directly impact
the risk potential of expansive soils across the State of Texas (State of Texas HMP 2018).
Changes since the 2017 HMP
The location of expansive soils within the County has not changed since the Galveston County 2017 HMP.
However, the 2017 HMP did not include an analysis of the vulnerable buildings. The analysis suggests that
Bayou Vista is especially vulnerable to expansive soils, yet the previous plan stated it was only moderately
Section 4.3.5: Extreme Temperature
Galveston County, TX | Hazard Mitigation Plan 4-52
2022 Update
vulnerable. Furthermore, since the population of the County has increased since the 2017 HMP, more people are
vulnerable to the expansive soils hazard.
4.3.5 Extreme Temperature
The following section provides the hazard profile and vulnerability assessment for the extreme temperature
hazard in Galveston County.
Profile
Hazard Description
Extreme temperature includes both heat and cold events, which can have a significant impact to human health,
commercial/agricultural businesses, and primary and secondary effects on infrastructure (e.g., burst pipes and
power failure). What constitutes extreme cold or extreme heat can vary across different areas of the country,
based upon what the population is accustomed.
Extreme Heat
Extreme heat is defined as summertime temperatures that are much hotter and/or humid than average. Because
some areas are hotter than others, extreme heat temperatures depend on what’s considered average for a
particular location at that time of year (CDC 2017). A heat wave is a period of abnormally hot weather generally
lasting more than two days. Heat waves can occur with or without high humidity. They have potential to cover
a large area, exposing a high number of people to hazardous heat (NWS n.d.). Extreme heat during the summer
months is a common occurrence in the State of Texas, including Galveston County.
Extreme Cold
Extreme cold events are when temperatures drop well below normal in an area. What constitutes as extreme cold
varies in different parts of the country. In the southern United States, near freezing temperatures are considered
extreme cold. Freezing temperatures can cause severe damage to citrus fruit crops and other veg etation. Pipes
may freeze and burst in homes that are poorly insulated or without heat (NWS n.d.). Galveston County typically
does not experience extreme cold; however, the County does have a history of occurrence for extreme cold
temperatures.
Extent
Extreme Heat
The extent of extreme heat temperatures generally is measured through
the Heat Index, identified in Figure 4-17. Created by the NWS, the Heat
Index is a chart that accurately measures what the temperature feels like
to the human body when relative humidity is combined with the air
temperature (NWS n.d.). To determine the Heat Index, the temperature
and relative humidity are needed. Once both values are identified, the
Heat Index is the corresponding number of both the values. This
provides a measure of how temperatures feel; however, the values are
devised for shady, light wind conditions. Exposure to full sun can
increase the index by up to 15 degrees.
Relative humidity is the amount of
moisture in the air at a certain
temperature compared to what the air
can “hold” at that temperature…it is
measured as a percentage or ratio of the
amount of water vapor in a volume of
air RELATIVE to a given temperature
and the amount it can hold at that given
temperature. Warm air can hold more
moisture than cold air.
Section 4.3.5: Extreme Temperature
Galveston County, TX | Hazard Mitigation Plan 4-53
2022 Update
Figure 4-17 Heat Index Chart
Source: NWS
Each National Weather Service office issues some or all of the following heat-related products as conditions
warrant (Table 4-18):
Table 4-18 National Weather Service Alerts for Extreme Heat
Alert Criteria
Excessive Heat Warning—Take
Action!
An Excessive Heat Warning is issued within 12 hours of the onset of extremely
dangerous heat conditions. The general rule of thumb for this Warning is when the
maximum heat index temperature is expected to be 105° or higher for at least 2 days
and night time air temperatures will not drop below 75°; however, these criteria vary
across the country, especially for areas not used to extreme heat conditions. If you
don't take precautions immediately when conditions are extreme, you may become
seriously ill or even die.
Excessive Heat Watches—Be
Prepared!
Heat watches are issued when conditions are favorable for an excessive heat event in
the next 24 to 72 hours. A Watch is used when the risk of a heat wave has increased
but its occurrence and timing is still uncertain.
Heat Advisory—Take Action!
A Heat Advisory is issued within 12 hours of the onset of extremely dangerous heat
conditions. The general rule of thumb for this Advisory is when the maximum heat
index temperature is expected to be 100° or higher for at least 2 days, and night time
air temperatures will not drop below 75°; however, these criteria vary across the
country, especially for areas that are not used to dangerous heat conditions. Take
precautions to avoid heat illness. If you don't take precautions, you may become
seriously ill or even die.
Excessive Heat Outlooks—Be
Aware!
The outlooks are issued when the potential exists for an excessive heat event in the
next 3-7 days. An Outlook provides information to those who need considerable lead-
time to prepare for the event.
Extreme Cold
The extent (severity or magnitude) of extreme cold temperatures is generally measured through the Wind Chill
Temperature (WCT) Index. The WCT Index uses advances in science, technology, and computer modeling to
Section 4.3.5: Extreme Temperature
Galveston County, TX | Hazard Mitigation Plan 4-54
2022 Update
provide an accurate, understandable, and useful formula for calculating the dangers from wind chill. For details
regarding the WCT Index, refer to: http://www.nws.noaa.gov/om/winter/windchill.shtml
Figure 4-18. NWS WCT Index
Source: (NWS n.d.)
The NWS provides alerts when Wind Chill indices approach hazardous levels. Table 4-19 explains these alerts.
Table 4-19. National Weather Service Alerts for Extreme Cold
Alert Criteria
Wind Chill Warning – Take Action!
NWS issues a wind chill warning when dangerously cold wind chill values are
expected or occurring. If you are in an area with a wind chill warning, avoid going
outside during the coldest parts of the day. If you do go outside, dress in layers, cover
exposed skin, and make sure at least one other person knows your whereabouts.
Update them when you arrive safely at your destination.
Wind Chill Watch – Be Prepared
NWS issues a wind chill watch when dangerously cold wind chill values are possible.
As with a warning, adjust your plans to avoid being outside during the coldest parts of
the day. Make sure your car has at least a half a tank of gas and update your winter
survival kit.
Wind Chill Advisory – Be Aware
NWS issues a wind chill advisory when seasonably cold wind chill values, but not
extremely cold values are expected or occurring. Be sure you and your loved one’s
dress appropriately and cover exposed skin when venturing outdoors.
Source: (NWS n.d.)
Worst-Case Scenario
An extreme temperature event could impact the entire population of Galveston County. The vulnerable
populations (over 65 and under 5, below poverty threshold) would be more susceptible to warmer or colder
temperatures. Extreme cold temperatures could result injuries associated with an interruption of energy supplies
and lack of access to medical care caused by snow or ice. Extreme heat worst-case scenario would be a multi-
day event of temperatures with a heat index reaching 113°F, like that experienced in June 2019. Those that are
outside could be more vulnerable to heat-related illnesses. Extreme cold worst-case scenario would be a multi-
day event of temperatures only reaching 34°F, like that experienced during the February 2021 snow/cold event.
Another event like this could lead to power outages, no running water, frozen pipes, and minimal heat sources.
Section 4.3.5: Extreme Temperature
Galveston County, TX | Hazard Mitigation Plan 4-55
2022 Update
Location
Extreme temperature events can occur in any area of Galveston County. Metropolitan areas could experience
more extreme heat events due to urban heat islands. Heat island describes built up areas that are hotter than
nearby rural areas (Figure 4-19). According to the U.S. EPA, the annual mean air temperature of a city with 1
million people or more can be 1.8–5.4°F warmer than its surroundings. In the evening, the difference can be as
high as 22°F. Heat islands can affect communities by increasing summertime peak energy demand, air
conditioning costs, air pollution and greenhouse gas emissions, heat-related illness and mortality, and water
pollution (EPA 2021).
Figure 4-19. Urban Heat Island
Source: (NASA/JPL-Caltech 2021)
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
extreme temperatures in Galveston County. According to the NOAA-NCEI Storm Events Database, Galveston
County has been impacted by one extreme temperature event between 1996 and 2021.
Table 4-20. Extreme Temperature Events in Galveston County, 1996-2021
Hazard Type
Number of
Occurrences
Between 1996
and 2021 Total Fatalities Total Injuries
Total Property
Damage ($)
Total Crop
Damage ($)
Heat 8 3 0 $0 $0
Cold 1 9 0 $12 million $0
Source: NOAA-NCEI 2021, Galveston HMP 2017
Note: Due to limitations in data, not all extreme temperature events occurring between 1996 and 2021 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated
Between 1953 and 2021, the State of Texas was included in two extreme temperature-related disaster
declarations related to cold temperatures. Of those declarations, Galveston County was included in the February
2021 Severe Winter Storm declaration (DR-4586).
Section 4.3.5: Extreme Temperature
Galveston County, TX | Hazard Mitigation Plan 4-56
2022 Update
According to the Houston/Galveston NWS Station, the local weather data collection center with comprehensive
data in the County, the mean number of days between 2000 and 2021 with a daily maximum temperature equal
to or greater than 90°F was 67 days. The greatest number of days which the County experienced extreme heat
is 31 in 2016, while the highest temperature recorded was 104°F on September 5, 2000.
Table 4-21. Monthly Number of Days with Maximum Temperature ≥ 90°F
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
2000 0 0 0 0 0 0 27 26 9 0 0 0 62
2001 0 0 0 0 0 2 18 19 1 0 0 0 40
2002 0 0 0 0 0 1 11 22 6 1 0 0 41
2003 0 0 0 0 1 5 5 21 1 0 0 0 33
2004 0 0 N/A 0 0 1 12 17 12 0 0 0 N/A
2005 0 0 0 0 2 17 27 29 23 1 0 0 99
2006 0 0 0 0 0 11 12 22 9 1 0 0 55
2007 0 0 0 0 0 1 2 22 7 0 0 0 32
2008 0 0 0 0 0 28 26 19 N/A 0 0 0 N/A
2009 0 0 0 0 0 16 27 30 6 N/A 0 0 N/A
2010 0 0 0 0 1 10 10 31 13 0 0 0 65
2011 0 0 0 1 4 25 30 30 13 0 0 0 103
2012 0 0 0 0 2 11 20 26 8 0 0 0 67
2013 0 0 0 0 0 19 24 19 9 0 0 0 71
2014 0 0 0 0 0 4 22 24 8 0 0 0 58
2015 0 0 0 0 0 5 30 23 5 1 0 0 64
2016 0 0 0 0 0 3 29 19 17 0 0 0 68
2017 0 0 0 0 1 2 22 19 14 5 0 0 63
2018 0 0 0 0 1 18 19 28 4 0 0 0 70
2019 0 0 0 0 0 12 28 30 22 7 0 0 99
2020 0 0 0 1 1 11 26 30 15 0 0 0 84
2021 0 0 0 0 0 15 20 26 16 1 0 N/A N/A
Mean 0 0 0 0 1 10 20 24 10 1 0 0 67
Max 0
2021
0
2021
0
2021
1
2020
4
2011
28
2008
30
2015
31
2010
23
2005
7
2019
0
2021
0
2020
103
2011
Min 0
2021
0
2021
0
2021
0
2021
0
2021
0
2000
2
2007
17
2004
1
2003
0
2020
0
2021
0
2020
32
2007
Source: (NWS 2021)
Note: N/A = indicates that there is no available data
According to the Houston/Galveston NWS Station, the local weather data collection center with comprehensive
data in the County, the mean number of days between 2000 and 2021 with a daily maximum temperature equal
to or less than 32°F was 2 days. The greatest number of days which the County experienced extreme cold is 8
in 2011, while the lowest temperature recorded was 20°F on February 16, 2021.
Table 4-22. Monthly Number of Days with Maximum Temperature ≤ 32°F
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
2000 0 0 0 0 0 0 0 0 0 0 0 0 0
2001 2 0 0 0 0 0 0 0 0 0 0 0 2
2002 1 1 2 0 0 0 0 0 0 0 0 0 4
2003 1 0 0 0 0 0 0 0 0 0 0 0 1
2004 0 0 N/A 0 0 0 0 0 0 0 0 1 N/A
2005 0 0 0 0 0 0 0 0 0 0 0 0 0
2006 0 0 0 0 0 0 0 0 0 0 0 0 0
2007 0 0 0 0 0 0 0 0 0 0 0 0 0
2008 0 0 0 0 0 0 0 0 N/A 0 0 0 N/A
2009 0 0 0 0 0 0 0 0 0 N/A 0 0 N/A
2010 5 0 0 0 0 0 0 0 0 0 0 0 5
Section 4.3.5: Extreme Temperature
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2022 Update
Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
2011 1 8 0 0 0 0 0 0 0 0 0 0 9
2012 0 0 0 0 0 0 0 0 0 0 0 0 0
2013 0 0 0 0 0 0 0 0 0 0 0 0 0
2014 6 0 0 0 0 0 0 0 0 0 0 0 6
2015 1 0 0 0 0 0 0 0 0 0 0 0 1
2016 0 0 0 0 0 0 0 0 0 0 0 0 0
2017 1 0 0 0 0 0 0 0 0 0 0 0 1
2018 5 0 0 0 0 0 0 0 0 0 0 0 5
2019 0 0 0 0 0 0 0 0 0 0 0 0 0
2020 0 0 0 0 0 0 0 0 0 0 0 0 0
2021 0 3 0 0 0 0 0 0 0 0 0 N/A N/A
Mean 1 1 0 0 0 0 0 0 0 0 0 0 2
Max 6
2014
8
2011
2
2002
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
1
2004
9
2011
Min 0
2021
0
2020
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
0
2021
0
2020
0
2020
Source: (NWS 2021)
Note: N/A = indicates that there is no available data
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. Seventy years from now, Texas is likely to have three or four times as many days per year
above 100°F as it has today (EPA 2016). With the increase in temperatures, heat waves will become more
frequent and intense, increasing heat-related illness and death, and posing new challenges to the energy system,
air quality and agriculture.
Probability of Future Occurrences
It is anticipated that the County will experience extreme temperature events each year, with a majority of the
days being extreme heat days. The probability of future occurrences for extreme temperatures can be determined
by assessing historical averages. Based on the information provided by the National Weather Service, the
County can expect, on average, approximately 52 days a year with temperatures greater than or equal to 90°F.
Additionally, the County can expect, on average, approximately eight days each year with temperatures less than
or equal to 32°F.
Table 4-23. Probability of Occurrences of Extreme Temperature Events
Hazard Type
Number of Occurrences Between
2000 and 2021
% chance of occurrence in any
given year
Temperature ≥ 90°F 1,084 100%
Temperature ≤ 32°F 35 100%
Total 1,119 100%
Source: (NWS 2021)
Notes: Probability was calculated using the available data provided in the National Weather Service data for the Houston/Galveston Station.
Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act and selected extreme
temperature events since 1968. Due to limitations in data, not all extreme temperature events occurring between 1954 and 1996 are
accounted for in the tally of occurrences. As a result, the number of hazard occurrences is underestimated.
Based on historical records and input from the Steering Committee, the probability of occurrence for extreme
temperatures in Galveston County is considered frequent (100% chance occurring; occurs multiple times a
year). Refer to Section 4.4 for additional information on the hazard ranking methodology and probability
criteria.
Section 4.3.5: Extreme Temperature
Galveston County, TX | Hazard Mitigation Plan 4-58
2022 Update
Vulnerability Assessment
To understand risk, a community must evaluate what assets are exposed and vulnerable. For the extreme
temperature hazard, the entire County has been identified as exposed; therefore, all assets are potentially
vulnerable. The following text estimated potential impacts of extreme temperatures on the Galveston County.
Impact on Life, Health and Safety
The entire population (350,682) of Galveston County is exposed to the extreme temperature hazard. Extreme
temperature events have potential health impacts including injury and death. According to the Centers for Disease
Control and Prevention, populations most at risk to extreme cold and heat events include the following: 1) the
elderly, who are less able to withstand temperatures extremes due to their age, health conditions, and limited
mobility to access shelters; 2) infants and children up to four years of age; 3) individuals with chronic medical
conditions (e.g., heart disease, high blood pressure), 4) low-income persons that cannot afford proper heating and
cooling; and 5) the general public who may overexert during work or exercise during extreme heat events or
experience hypothermia during extreme cold events (CDC 2017a). The number of people vulnerable to extreme
temperatures are presented in Table 4-24.
Table 4-24. Vulnerable Populations in Galveston County
Jurisdiction
Over
65
Percent of
Jurisdiction
Total
Under
5
Percent of
Jurisdiction
Total
Poverty
Level
Percent of
Jurisdiction
Total
Bayou Vista (C) 619 35.1% 17 1.0% 64 3.6%
Clear Lake Shores (C) 304 24.2% 22 1.7% 8 0.6%
Dickinson (C) 2,786 13.4% 1,055 5.1% 3,402 16.3%
Friendswood (C) 5,648 13.7% 2,517 6.1% 1,611 3.9%
Hitchcock (C) 1,054 14.4% 728 10.0% 1,505 20.6%
Jamaica Beach (C) 175 16.2% 20 1.9% 90 8.3%
Kemah (C) 358 19.8% 152 8.4% 271 15.0%
La Marque (C) 2,377 13.2% 767 4.3% 2,227 12.4%
League City (C) 10,973 9.6% 7,980 7.0% 5,693 5.0%
Santa Fe (C) 2,495 19.6% 792 6.2% 1,501 11.8%
Tiki Island (V) 361 32.6% 5 0.5% 57 5.2%
Galveston County (Total) 46,103 13.1% 21,140 6.0% 37,264 10.6%
Source: 2015-2019 American Community Survey Estimates
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Exposure to excessive heat can pose a number of health risks to individuals. Table 4-25 and Table 4-26 identify
different health hazards related to extreme heat conditions.
Table 4-25. Health Effects of Extreme Cold
Health Hazard Symptoms
Wind Chill
Wind chill is not the actual temperature but rather how wind and cold feel on exposed skin. As the
wind increases, heat is carried away from the body at an accelerated rate, driving down the body
temperature. Animals are also affected by wind chill; however, cars, plants and other objects are not.
Frostbite
Frostbite is damage to body tissue caused by extreme cold. A wind chill of -20°F will cause frostbite
in just 30 minutes. Frostbite causes a loss of feeling and a white or pale appearance in extremities,
such as fingers, toes, ear lobes or the tip of the nose. If symptoms are detected, get medical help
immediately! If you must wait for help, slowly re-warm affected areas. However, if the person is
also showing signs of hypothermia, warm the body core before the extremities.
Section 4.3.5: Extreme Temperature
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2022 Update
Health Hazard Symptoms
Hypothermia
Hypothermia is a condition brought on when the body temperature drops to less than 95°F. It can
kill. For those who survive, there are likely to be lasting kidney, liver, and pancreas problems.
Warning signs include uncontrollable shivering, memory loss, disorientation, incoherence, slurred
speech, drowsiness, and apparent exhaustion.
Source: CDC 2020
Table 4-26. Health Effects of Extreme Heat
Health Hazard Symptoms
Sunburn Redness and pain. In severe cases: swelling of skin, blisters, fevers, and headaches
Dehydration Excessive thirst, dry lips, and slightly dry mucous membranes
Heat Cramps Painful spasms, usually in muscles of legs and abdomen, and possible heavy sweating
Heat Exhaustion Heavy sweating; weakness; cold, pale, and clammy skin; weak pulse; possible fainting and vomiting
Heat Stroke High body temperature (104ºF or higher), hot and dry skin, rapid and strong pulse, and possible
coma
Source: CDC 2020
Meteorologists can accurately forecast extreme heat and cold event development and the severity of the
associated conditions with several days of lead time. These forecasts provide an opportunity for public health
and other officials to notify vulnerable populations, implement short-term emergency response actions, and focus
on surveillance and relief efforts on those at greatest risk. Adhering to extreme temperature warnings can
significantly reduce the risk of temperature-related deaths.
Impact on General Building Stock
All the building stock in the County is exposed to the extreme temperature hazard. Extreme heat generally does
not impact buildings; however, elevated summer temperatures increase the energy demand for cooling. Losses
can be associated with the overheating of heating, ventilation, and air conditioning (HVAC) systems. Extreme
cold temperature events can damage buildings through freezing/bursting pipes and freeze/thaw cycles, as well
as increasing vulnerability to home fires. Additionally, manufactured homes (mobile homes) and antiquated or
poorly constructed facilities can have inadequate capabilities to withstand extreme temperatures.
Impact on Critical Facilities
All critical facilities in the County are exposed to the extreme temperature hazard. Impacts to critical facilities
are the same as described for general building stock. Additionally, it is essential that critical facilities remain
operational during natural hazard events. Extreme heat events can sometimes cause short periods of utility
failures, commonly referred to as brown-outs, due to increased usage from air conditioners and other energy-
intensive appliances. Similarly, heavy snowfall and ice storms, associated with extreme cold temperature events,
can cause power interruption. Backup power is recommended for critical facilities and infrastructure.
Impact on Economy
Extreme temperature events also have impacts on the economy, including loss of business function and damage
to and loss of inventory. Business-owners can be faced with increased financial burdens due to unexpected
repairs caused to the building (e.g., pipes bursting), higher than normal utility bills, or business interruption due
to power failure (i.e., loss of electricity, telecommunications).
Future Changes that May Impact Vulnerability
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
Section 4.3.6: Flood
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2022 Update
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development and Change in Population
The ability of new development to withstand extreme temperature impacts lies in sound land use practices and
consistent enforcement of codes and regulations for new construction. New development will change the
landscape where buildings, roads, and other infrastructure potentially replace open land and vegetation. Surfaces
that were once permeable and moist are now impermeable and dry. These changes cause urban areas to become
warmer than the surrounding areas forming an island of higher temperatures (EPA 2009).
Climate Change
As the climate warms, extreme cold events might decrease in frequency, while extreme heat events might
increase in frequency; the shift in temperatures could also result in hotter extreme heat events. With increased
temperatures, vulnerable populations could face increased vulnerability to extreme heat and its associated
illnesses, such as heatstroke and cardiovascular and kidney disease. Additionally, as temperatures rise, more
buildings, facilities, and infrastructure systems may exceed their ability to cope with the heat.
Change of Vulnerability Since the 2017 HMP
Overall, the entire County remains vulnerable to extreme temperatures. As existing development and
infrastructure continue to age, they can be at increased risk to failed utility systems (e.g., HVAC) if they are not
properly maintained. Similarly, an increase in the elderly population remaining in the County increases the
vulnerable population.
4.3.6 Flood
The following section provides the hazard profile and vulnerability assessment for the flood hazard in Galveston
County.
Profile
Hazard Description
Floods are one of the most common natural hazards in the U.S. They can develop slowly over a period of days
or develop quickly, with disastrous effects that can be local (impacting a neighborhood or community) or
regional (affecting entire river basins, coastlines and multiple counties or states) (FEMA 2017). As defined in
the State of Texas HMP, floods are the accumulation of water within a water body and the overflow of excess
water into adjacent floodplain lands (Texas Division of Emergency Management 2013).
In hydrologic analysis, runoff is that portion of rainfall which, in combination with other factors, contributes to
the stream flow of any surface drainage way. When runoff exceeds the carrying capacity of the stream or
drainage, flooding occurs. Runoff is a product of two major groups of factors, climate and physiographic.
Climatic factors may include precipitation, evaporation, transpiration, and interception. Physiographic factors
would include the characteristics of the watershed such as size, shape and slope of the basin’s drainage area, the
general land use within the basin. Average annual runoff decreases unevenly moving east to west across Texas,
the localized variations based on these factors listed above (Texas Division of Emergency Management 2013).
Figure 4-20 illustrates the annual average runoff from precipitation across the State. In Galveston County, the
average runoff is fourteen to eighteen inches.
4.3.6: Flood
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2022 Update
Figure 4-20 Annual Average Runoff from Precipitation, in Inches
Source: (Texas Division of Emergency Management 2013)
When surface water runoff enters into streams, rivers, or dry creek beds, riverine flooding conditions occurs
whenever the water carrying capacity of the water channel is compromised by excess runoff (Texas Division of
Emergency Management 2013).
If the local basin drainage area is relatively flat, shallow, slow-moving floodwater can last for days. In drainage
areas with substantial slope, or the channel is narrow and confined, rapidly moving and extreme high water
conditions, called a flash flood, can occur (Texas Division of Emergency Management 2013).
Types of Flooding
Flooding generally takes one of the following forms:
• Riverine Flooding—Riverine flooding occurs when rivers overflow their banks in response to excessive
precipitation levels and water runoff volumes within the watershed. Riverine floodplains may be broad,
as when a river crosses an extensive flat landscape, or narrow, as when a river is confined in a canyon.
• Coastal Flooding—Coastal flooding is primarily caused by storm surge, a cascading effect of hurricanes
and coastal storms that pushes water toward the shore. The result can be waves that extend further
inland, causing damage to development that would not normally be subject to wave action. Storm surge
heights, and associated waves, are dependent upon the local width of the continental shelf and the depth
of the ocean bottom. A narrow shelf, or one that drops steeply from the shoreline and subsequently
produces deep water close to the shoreline, tends to produce a lower surge but higher and more powerful
storm waves. Due to the high risk and vulnerability to this flood specific hazard, it was analyzed
independently in this chapter rather than as a cascading effect of hurricanes.
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• Flash Flooding—Most flash flooding is caused by slow-moving thunderstorms in a local area or by
heavy rains associated with hurricanes and tropical storms. However, flash flooding events can also
occur from accelerated snow melt due to heavy rains, a dam or levee failure within minutes or hours of
heavy amounts of rainfall, or from a sudden release of water held by an ice jam. Although flash flooding
occurs often along mountain streams, it is also common in urbanized areas where much of the ground
is covered by impervious surfaces. Flash flood waters move at very high speeds, uprooting trees,
destroying buildings, and obliterating bridges and roads.
• Urban Flooding—Urban flooding occurs when development has obstructed the natural flow of water
and decreased the ability of natural groundcover to absorb and retain surface water runoff.
Location
Flooding potential is influenced by climatology, meteorology, and topography (elevations, latitude, and water
bodies and waterways). Flooding potential for each type of flooding that affects the County is described in the
subsections below.
Coastal Flooding
Coastal flooding and storm surge are most likely to affect the southwestern part of the planning area closest to
the coastline, including Galveston Island and the Bolivar Peninsula.
Riverine Flooding
The bayous and creeks are susceptible to riverine flooding during heavy rainfall events.
Flash Flooding
Flash floods can occur anywhere in the planning area depending on intensity of rainfall, but areas below streams
or other bodies of water are more susceptible to flash floods if an embankment fails suddenly.
Urban/Stormwater Flooding
The entire built planning area may be affected by urban flooding during heavy rainfall events, especially where
stormwater drainage infrastructure is aging or becomes blocked.
Floodplains
A floodplain is defined as the land
adjoining the channel of a river,
stream, ocean, lake, or other
watercourse or water body that
becomes inundated with water
during a flood. In Galveston
County, floodplains line the
rivers, streams, and bayous of the
County. The boundaries of the
floodplains are altered as a result
of changes in land use, the amount
of impervious surface, placement
of obstructing structures in floodways, changes in precipitation and runoff patterns, improvements in technology
for measuring topographic features, and utilization of different hydrologic modeling techniques.
Source: FEMA 2009
4.3.6: Flood
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Flood hazard areas are identified as Special
Flood Hazard Area (SFHA). SFHA are
defined as the area that will be inundated by
the flood event having a 1 percent chance of
being equaled to or exceeded in any given
year. The 1 percent annual chance flood is also
referred to as the base flood or 100-year flood.
A 100-year floodplain is not a flood that will
occur once every 100 years; the designation
indicates a flood that has a 1-percent chance of
being equaled or exceeded each year. Thus,
the 100-year flood could occur more than once
in a relatively short period of time. Similarly,
the moderate flood hazard area (500-year
floodplain) will not occur every 500 years but
is an event with a 0.2-percent chance of being
equaled or exceeded each year (FEMA 2020).
The 1-percent annual chance floodplain
establishes the area that has flood insurance
and floodplain management requirements.
Locations of flood zones in the County as depicted on the FEMA preliminary Digital Flood Insurance Rate Map
(DFIRM) are illustrated in Figure 4-21. Flood hazard zones occur throughout the County, with the largest areas
along the bay areas. The Digital Flood Insurance Rate Map (DFIRM) data provided by FEMA for the County
show the following flood hazard areas:
• 1-Percent Annual Chance Flood Hazard: Areas subject to inundation by the 1-percent-annual-chance
flood event. This includes Zone AE, and Zone. Mandatory flood insurance requirements and floodplain
management standards apply. Base flood elevations are provided in Zone AE. Zone VE (coastal areas)
has associated flood depths derived from detailed analyses.
• 0.2-Percent Annual Chance Flood Hazard: Area of moderate flood hazard, usually depicted on FIRMs
as the 500-year flood level or Shaded X Zone.
• 0.2-Percent Annual Chance Flood Hazard: Area of minimal flood hazard, usually depicted on FIRMs
as the 500-year flood level or Unshaded X Zone.
Flood Map Terms
•Flood hazard areas identified on the Flood Insurance Rate
Map are identified as a Special Flood Hazard Area (SFHA).
•SFHA = the area that will be inundated by the flood event
having a 1-percent chance of being equaled or exceeded in
any given year.
•1-percent annual chance flood = the base flood or 100-year
flood.
•SFHAs are labeled as Zone A, Zone AO, Zone AH, Zones A1-
A30, Zone AE, Zone A99, Zone AR, Zone AR/AE, Zone
AR/AO, Zone AR/A1-A30, Zone AR/A, Zone V, Zone VE, and
Zones V1-V30.
•Zone B or Zone X (shaded) = Moderate flood hazard areas
and are the areas between the limits of the base flood and
the 0.2-percent-annual-chance (or 500-year) flood.
•Zone C or Zone X (unshaded) = Areas of minimal flood
hazard, which are the areas outside the SFHA and higher
than the elevation of the 0.2-percent-annual-chance flood,
are labeled
Source: (FEMA 2020)
4.3.6: Flood
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2022 Update
Figure 4-21. FEMA Flood Hazard Areas in Galveston County
4.3.6: Flood
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2022 Update
Flood Insurance in Galveston County
National Flood Insurance Program
The unincorporated areas of Galveston County and most the incorporated areas participating in this plan update
also participate in the NFIP with nearly 59,000 insurance policies in force providing over $17.2 billion in
insurance coverage. According to FEMA statistics, 52,601 flood insurance claims were paid between May 26,
1970 and September 30, 2021, for a total of over $2.1 billion, an average of $40,997 per claim. Table 4-27 lists
flood insurance statistics that help identify vulnerability in the planning area.
Table 4-27 Flood Insurance Statistics
Community
Date of Entry
Initial FIRM
Effective
Date
# of Flood
Insurance
Policies as of
09/30/2021
Insurance in
Force
Total
Annual
Premium
Claims, as of
09/30/2021
Value of
Claims paid,
as of
09/30/2021
Bayou Vista 04/09/1971 532 $139,915,400 $639,285 137 $3,425,622
Clear Lake Shores 10/23/1970 545 $141,502,700 $442,823 1,199 $26,600,777
Dickinson 04/08/1971 3,911 $1,167,363,200 $2,773,504 2,595 $239,101,802
Friendswood 04/08/1971 6,308 $2,083,467,400 $3,164,154 4,005 $255,175,550
Galveston County
(Unincorporated
Areas)
03/03/1972 7,518 $2,100,837,400 $9,503,247 16,433 $669,668,372
Galveston (City) 04/09/1971 17,235 $4,255,763,500 $24,979,053 18,072 $770,374,418
Hitchcock 05/26/1970 1,089 $281,539,900 $1,028,541 1,461 $39,676,284
Jamaica Beach 11/17/1970 912 $250,219,900 $970,015 1,573 $22,541,508
Kemah 04/08/1971 634 $194,966,900 $556,068 1,350 $42,403,304
La Marque 06/05/1970 2,007 $567,441,500 $1,167,140 1,640 $32,414,112
League City 05/26/1970 19,704 $6,480,149,700 $9,883,972 5,375 $250,669,561
Santa Fe 06/05/1970 2,029 $623,079,800 $1,018,853 716 $37,010,820
Tiki Island 04/08/1971 443 $120,537,100 $1,752,113 640 $6,519,690
Total - 58,956 $17,239,421,200 $55,105,264 52,601 $2,156,480,018
Properties constructed after a FIRM has been adopted are eligible for reduced flood insurance rates. Such
structures are less vulnerable to flooding since they were constructed after regulations and codes were adopted
to decrease vulnerability. Properties built before a FIRM is adopted are more vulnerable to flooding because
they do not meet code or are located in hazardous areas. The first FIRMs in Galveston County were available in
1971.
Repetitive Loss and Severe Repetitive Loss Properties
A high priority in Texas and nationwide is the reduction of structures with repetitive losses. These structures
strain NFIP. They increase the NFIP’s annual losses and the need for borrowing and, more importantly, they
drain resources needed to prepare for catastrophic events. The NFIP defines a repetitive loss property (RL) as
“any insurable building for which two or more claims of more than $1,000 were paid by the NFIP within any
rolling 10‐year period since 1978. At least, two of the claims must be more than 10‐days apart.”
The Flood Insurance Reform Act of 2004 identified another category of repetitive loss. Severe repetitive loss
(SRL) is defined as “a single family property (consisting of one‐to‐four residences) that is covered under flood
insurance by the NFIP and has incurred flood‐related damage for which four or more separate claim payments
(building and contents) have been paid under flood insurance coverage with the amount of each claim payment
exceeding $5,000 and with cumulative amount of such claims payments exceeding $20,000; or for which at least
two separate claim payments (building payments only) have been made with the cumulative amount of the
building portion of such claims exceeding the reported value of the property.”
4.3.6: Flood
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2022 Update
The resolution of the RL data accessible by the County to support this planning effort was limited by FEMA’s
Privacy Act Policies and the time associated with processing the requisite Information Sharing Access
Agreement (ISAA). Therefore, data from September 2014 was used to determine how many properties that
remain unmitigated are in the program compared to how many have been mitigated (Table 4-28).
Table 4-28. Summary of Repetitive Flood Properties by Occupancy Type and Number of Properties
Mitigated
Community
2-4
Family
Assmd.
Condo
Non-
Resident
Other
Resident
Single
Family
Total RF
Properties
No. of
Mitigated
Properties
Bayou Vista 0 0 0 0 45 45 9
Clear Lake Shores 1 2 13 1 86 103 53
Dickinson N/A N/A N/A N/A N/A 253 N/A
Friendswood 1 4 5 2 295 307 129
Hitchcock 0 1 4 0 100 105 34
Jamaica Beach 0 1 0 0 44 45 4
Kemah 2 3 30 3 74 112 79
La Marque 0 1 5 0 69 75 6
League City 1 3 7 2 220 233 111
Santa Fe 0 0 7 1 114 122 11
Tiki Island 0 0 0 0 2 2 0
Total* 5 15 71 9 1,049 1,149 436
*includes totals for participating jurisdictions in the 2022 HMP update; City of Dickinson did not participate in the last plan
and data is incomplete. A Countywide action is included in this plan to obtain RL and SRL data for jurisdictions.
Community Rating System
The CRS is a voluntary program within the NFIP that encourages floodplain management activities that exceed
the minimum NFIP requirements. Flood insurance premiums are discounted to reflect the reduced flood risk
resulting from community actions meeting the following three goals of the CRS:
• Reduce flood losses.
• Facilitate accurate insurance rating.
• Promote awareness of flood insurance.
For participating communities, flood insurance premium rates are discounted in increments of 5 percent. For
example, a Class 1 community would receive a 45 percent premium discount, and a Class 9 community would
receive a 5 percent discount. (Class 10 communities are those that do not participate in the CRS; they receive no
discount.) The discount partially depends on location of the property. Properties outside the SFHA receive
smaller discounts: a 10-percent discount if the community is at Class 1 to 6 and a 5-percent discount if the
community is at Class 7 to 9. The CRS classes for local communities are based on 18 creditable activities in the
following categories:
• Public information
• Mapping and regulations
• Flood damage reduction
• Flood preparedness
CRS activities can help to save lives and reduce property damage. Communities participating in the CRS
represent a significant portion of the nation’s flood risk; over 66 percent of the NFIP’s policy base is located in
these communities. Communities receiving premium discounts through the CRS range from small to large and
represent a broad mixture of flood risks, including both coastal and riverine flood risks.
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2022 Update
Seven cities in the County currently participate in the CRS program, representing 96.3 percent of the planning
area policy base. Their CRS status is summarized in Table 4-29. The total annual savings on flood insurance
premiums within the planning area is $33.65 million. Many of the mitigation actions identified in this plan are
creditable activities under the CRS program. Therefore, successful implementation of this plan offers the
potential for these communities to enhance their CRS classifications and for currently non-participating
communities to join the program.
Table 4-29 CRS Community Status in the Planning Area
Community
NFIP
Community #
CRS Entry
Date
Current CRS
Classification
% Premium Discount,
SFHA/non-SFHA Total Premium Savings
Dickinson 481569 10/01/2012 8 10/5 $277,350/$138,675
Friendswood 485468 10/01/1991 7 15/5 $126,963/$158,208
Jamaica Beach 481271 10/01/2018 8 10/5 $97,002/$48,501
Kemah 485481 10/01/1992 8 10/5 $55,607/$27,803
League City 485488 10/01/1992 5 25/10 $2,470,993/$988,397
Tiki Island 481585 10/01/2001 7 15/5 $262,817/$87,606
Extent
The severity of a flood event is typically determined by a combination of several factors including stream and
river basin topography and physiography; precipitation and weather patterns; recent soil moisture conditions;
and degree of vegetative clearing and impervious surface. Generally, floods are long-term events that may last
for several days. Regarding the riverine flood hazard, once a river reaches flood stage, flood extent or severity
categories used by the NWS include minor flooding, moderate flooding, and major flooding. Each category is
defined as follows, based on property damage and level of public threat:
• Minor Flooding – minimal or no property damage, but possibly some public threat or inconvenience.
• Moderate Flooding – some inundation of structures and roads near streams. Some evacuations of people
and/or transfer of property to higher elevations are necessary.
• Major Flooding – extensive inundation of structures and roads. Significant evacuations of people and/or
transfer of property to higher elevations (NWS 2011).
USGS uses stream gages to determine the severity of flood at different points along a body of water. There a re
eight gages in or near Galveston County. The flood stage is identified for one gage; however, flood stages were
not identified for the other gages. The County relies on the gages to determine the height of the river during
heavy rain events and to determine whether or not residents need to evacuate. Table 4-30 shows the gages in
the County with their determined flood stage and their record flood event. The USGS website provides details
about each of the gages (https://waterwatch.usgs.gov/index.php) and the gage heights of flooding events. The
NWS provides the different flood stages for the gages (https://water.weather.gov/ahps/).
Table 4-30. Stream Gage Statistics for the Vicinity of Galveston County
Gage Site
Number Site Name
Action Stage
(feet)
Minor Flood
Stage
(feet)
Moderate
Flood Stage
(feet)
Major Flood
Stage
(feet) Record Flood
HCCT2 Clear Creek at Friendswood 7 12 16 21 24.25 ft on
08/29/2017
EPTT2 Tide Station (HGX) at San Leon 3.75 4 4.5 5 N/A
GRRT2 Tide Station (HGX) at Galveston
Railroad Bridge 3.25 3.5 4 4.5 N/A
LUIT2 Tide Station (HGX) at San Luis
Pass 3.25 3.5 4 4.5 N/A
GTOT2 Tide Station (HGX) at Nos
Station Pier 21 Galveston 3.75 4 4.5 5 N/A
GNJT2 Tide Station (HGX) at Galveston
Bay Entrance North Jetty 3.25 3.5 4 4.5 N/A
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Gage Site
Number Site Name
Action Stage
(feet)
Minor Flood
Stage
(feet)
Moderate
Flood Stage
(feet)
Major Flood
Stage
(feet) Record Flood
RLOT2 Tide Station (HGX) at Rollover
Pass 3.25 3.5 4.5 5 N/A
Source: (NWS 2021)
N/A: Not Available
Worst-Case Scenario
Galveston County experienced its worst-case flood scenario in 2017 during Hurricane Harvey. Hurricane
Harvey was identified as a 500-year and even a 1,000-year event. Meaning, a storm of this magnitude has a 0.2-
annual chance to 0.1-percent annal chance of occurring in any given year. About 7,000 homes and 125
businesses were impacted by flood waters across the county. Many roads were inundated with water. There were
numerous water rescues. Stormwater systems were inundated, and pump stations were not able to function
properly because their limits were exceeded. This led to closed roadways, damaged infrastructure, ingress, and
egress issues, etc. The damages from Hurricane Harvey and the lessons learned from the response and recovery
will play a significant role in the County’s preparedness for future events.
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
flooding in Galveston County. Between 1953 and 2020, FEMA included the State of Texas in 53 flood-related
major disaster (DR) or emergency (EM) declarations. Generally, these disasters cover a wide region of the State;
therefore, they may have impacted many counties. Galveston County was included in ten of these flood-related
declarations; refer to Table 4-31.
Table 4-31. Flood-Related FEMA Declarations for Galveston County, 1953 to 2021
FEMA Declaration
Number Date(s) of Event Incident Type Incident Title
DR-398 July 11, 1973 Flood Severe Storms, Flooding
DR-595 July 28, 1979 Flood Storms, Flash Floods
DR-603 September 25, 1979 Flood Severe Storms, Flooding
DR-1041 October 14-November 8, 1994 Flood Severe Thunderstorms and Flooding
DR-1257 October 17-November 15, 1998 Flood Severe Storms, Flooding and Tornadoes
DR-1245 September 9-October 5, 1998 Severe Storm Hurricane Georges, Tropical Storm Frances
DR-1379 June 5-9, 2001 Coastal Storm Tropical Storm Allison
DR-1791 September 12-14 Hurricane Hurricane Ike
DR-4245 October 22-31, 2015 Severe Storm Severe Storms, Tornadoes, Straight-line Winds,
and Flooding
DR-4332 August 26-30, 2017 Hurricane Hurricane Harvey
Source: FEMA 2021
This HMP update includes known flood events that have impacted Galveston County between 2016 and 2021.
These events are shown in Table 4-32, The events listed in Table 4-32 represent only those that were reported
to the NOAA-NCEI Storm Events Database, FEMA, and the 2017 Galveston County HMP, and may not
represent all flood events that have occurred since 2016. For events prior to 2016, refer to the 2017 Galveston
County HMP.
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-69
2022 Update
Table 4-32. Flood Events in Galveston County, 2016 to 2021
Dates of
Event Event Type
FEMA
Declaration
Number
(if applicable) Fatalities Injuries Damages Event Details*
April 18, 2016 Flash Flood - - - -
Numerous flooded roadways in League City. Flood waters
were inundating numerous roads within the city of
Galveston.
May 19, 2016 Flash Flood - - - - Flash flooding occurred near the intersection of Interstate
45 and 61st Street in Galveston.
June 4, 2016 Flash Flood - - - - Harborside Drive was closed due to high water.
December 3,
2016 Flash Flood - - - $50,000
Numerous streets were inundated with flood waters nearing
homes in Texas City. Impassable roads due to high water
included the FM 1764 - Emmett Lowry Parkway and
Highway 146 intersection. There were also reports of
flooded streets in the town of La Marque.
March 29, 2017 Flash Flood - - - - Street flooding was reported across the Friendswood area.
April 18, 2017 Flash Flood - - - $104,000
Street flooding was causing vehicles to stall around the
College of the Mainland. The Amburn Street and
Monticello Drive intersection was flooded and impassable.
High flood water was also reported in La Marque at the
Gulf Freeway and FM 519 intersection. Water reported in
homes at Avenue M 1/2 and 24th Street, north of 32nd
Street and on Ave P at 28th Street in Santa Fe. Sections of
O and P Avenue near the 28th Street intersection were
closed due to flooding. Street flooding was also reported
along R, S and T Avenues at the 32nd and 33rd street
intersections. Approximately 8 roads were closed and
impassable due to flood waters within town limits.
May 9, 2016 Coastal Flood - - - -
The was minor water over wash at the intersection of
Highway 87 and Highway 124 due to the combination of
above normal tides and wave run up.
December 3,
2016 Coastal Flood - - - $20,000
A prolonged period of easterly winds south of a near
coastal warm front produced elevated water levels that
inundated sections of Galveston Island, including
downtown. Impassable roads due to high water included
the intersection of 38th and Winnie Street, 39th and Church
Street and the intersection of 51st Street and Harborside
Drive.
June 21-22,
2017 Tropical Storm - - - -
Due to Tropical Storm Cindy, water and debris covered a
low lying section of Highway 87 near its intersection with
Highway 124 which is an area that is especially vulnerable
to coastal flooding. Elsewhere, channels were elevated
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-70
2022 Update
Dates of
Event Event Type
FEMA
Declaration
Number
(if applicable) Fatalities Injuries Damages Event Details*
around Jamaica Beach and other west end communities of
Galveston Island, but there was little impact.
August 26-30,
2017 Flash Flood DR-4332 3 - $10,000,011,000
Due to Hurricane Harvey, approximately 7,000 homes and 125
businesses were impacted by flood waters across the county. Many
roads were inundated with water. There were numerous water
rescues.
October 20,
2017 Flash Flood - - - - Multiple roadways were flooded and impassable.
September 3,
2018 Flash Flood - - - $200,000
Significant flooding occurred on Galveston Island from
Jamaica Beach up into the city of Galveston as over 10
inches of rain fell in some spots. There were numerous road
closures with at least one washed out roadway in the town
of Jamaica Beach. There were reports of water within some
structures.
September 11,
2018 Flash Flood - - - $100,000
Flooding was reported on the College of the Mainland
campus. A few flooded residences had a half of a foot of
water in them along Meadowlark Lane in western Texas
City and western La Marque. There were numerous street
flooding reports.
September 11,
2018 Flash Flood - - - - Some roads along Dickinson Bayou were flooded.
September 12,
2018 Flash Flood - - - -
There was flooding along the Gulf Freeway-Interstate 45
that closed sections of the freeway between the FM 518 and
Highway 96 exits.
September 14,
2018 Flash Flood - - - -
There were flooded roads, with reports of water as high as
two feet, around Ball High School. Sections of Harborside
Drive-SH 275 from Interstate 45 east to Ferry Road were
closed due to high water.
September 29,
2018 Flash Flood - - - $50,000 Roads were impassable from the Downtown Galveston area
to across parts of the Port Bolivar area.
October 24,
2018 Flash Flood - - - -
There were reports of water near homes with flooded cars
and roadways in Santa Fe, Dickinson, and League City.
Some of the flooding occurred as Dickinson Bayou went
out of banks at SH 3 near Hughes Road.
October 24,
2018 Flash Flood - - - -
There were numerous reports of street flooding on the east
end of Galveston Island from Scholes Field eastward
towards Ferry Road. High water encroached the dorms at
Texas A&M-Galveston on Pelican Island with flooding
inundating the Strand and points along Harborside Road
towards Ferry Road.
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-71
2022 Update
Dates of
Event Event Type
FEMA
Declaration
Number
(if applicable) Fatalities Injuries Damages Event Details*
December 8,
2018 Flash Flood - - - - There was high flood water that caused the intersection of
the Gulf Freeway and Highway 96 to become impassable.
December 8,
2018 Flash Flood - - - - There were sections of Harborside Drive that became
impassable due to high flood waters.
December 27,
2018 Coastal Flood - - - - High water impacted several SH 87 locations on the east
end of Bolivar.
May 7, 2019 Flash Flood - - - -
There were numerous reports of either high water in low
lying locations or impassable roadways due to flooding.
There were flooded roads around Friendswood, League
City at the Gulf Freeway and Highway 96, the I-45 feeder
roads near FM 646 in Dickinson and in Texas City near the
high school.
May 9-10,
2019 Flash Flood - - - $20,000
Flash flooding lead to impassable roads that extended from
Friendswood and League City down the Gulf Freeway to
include, Dickinson, Texas City, and the city of Galveston.
One house flooded in Dickinson with some vehicle
flooding. Approximately 25 vehicles were flooded in Texas
City with some water entering the Heights Elementary
School.
May 22, 2019 Coastal Flood - - - -
Some low-lying beach front roads had some water on them,
and water was up to the seawall at some locations. Water
was also over parts of the Highway 87 and Highway 124
intersection on the Bolivar Peninsula.
September 18,
2019 Flash Flood - - - -
Flooding occurred on many roads in the Strand area as
water flowed over the curbs and sidewalks. Ferry Road
near UTMB became inundated and impassable due to
floodwaters.
October 24,
2019 Coastal Flood - - - -
Frenchtown Road on extreme western Bolivar peninsula
near the ferry dock became impassible due to bay water run
up during high tide.
May 15, 2020 Flash Flood - - - -
Numerous roadways were flooded in western Dickinson
and southern League City including, but not limited to, the
Bayou Lakes, Brentwood Estates and Bay Colony
neighborhoods.
August 26-27,
2020
Storm
Surge/Tide - - - -
Flooding of low-lying areas and roads. Beach erosion on
Gulf side. Tide gauges measured tides 3 to 4 feet above
MHHW. Bolivar Peninsula and Galveston Island, including
Jamaica Beach, with multiple roads closed.
September 21-
23, 2020
Tropical Storm
Beta - - - - Widespread coastal flooding occurred across coastal
Galveston County. Flooding was observed in San Leon,
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-72
2022 Update
Dates of
Event Event Type
FEMA
Declaration
Number
(if applicable) Fatalities Injuries Damages Event Details*
Bayou Vista, Clear Lake Shores, and Kemah. The Kemah
Boardwalk was flooded. Numerous instances of street
flooding and road closures were reported. Heavy rain from
the storm resulted in bayou and creek flooding, including
Clear Creek.
October 9,
2020 Hurricane - - - -
Due to Hurricane Delta, high surf and elevated tides lead to
mainly minor coastal flooding along Gulf facing beaches
and around Galveston Bay.
Sources: NOAA-NCEI 2021; State of Texas HMP 2018; Galveston County HMP 2017
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact information may vary and has been summarized in the above table
- Not available/not recorded
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-73
2022 Update
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016).
Probability of Future Occurrences
Table 4-33 summarizes data regarding the probability of occurrences of flood events in Galveston County based
on the historic record. The information used to calculate the probability of occurrences is based on the 2017
Galveston County HMP, the NOAA-NCEI Storm Events Database, and FEMA.
Table 4-33. Probability of Future Occurrence of Flood Events
Hazard Type
Number of Occurrences Between 1954
and 2021
% chance of occurrence in any
given year
Flood 96 100%
Source: NOAA-NCEI 2021; FEMA 2021; Galveston County HMP 2017
Note: The total number of events used to calculate the probability of occurrence for flooding in Galveston County includes those
listed in the NOAA-NCEI database and FEMA disaster declarations. Any recorded event type that resulted in flooding was including in the
number of occurrences. Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected
flood events since 1968. Due to limitations in data, not all flood events occurring between 1954 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated.
Galveston County is expected to continue experiencing the direct and indirect impacts of flood each year.
Ninety-six flood events in 24 years were recorded in Galveston County, giving the County a 100% chance of
being impacted by a flood in any given year, with four events occurring each year. Based on historical records
and input from the Steering Committee, the probability of occurrence for flood events in the City is considered
frequent (100% chance occurring; occurs multiple times a year). Refer to Section 4.4 for additional information
on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To assess Galveston County’s risk to the flood hazard, a spatial analysis was conducted using the best available
spatially delineated flood hazard areas. A quantitative assessment of exposure to the flood hazard was conducted
using the asset inventory developed for this plan and two mapped flood areas:
• The 1% annual chance flood hazard area; and
• The 0.2% annual chance flood hazard area
Impact on Life, Health and Safety
Impacts of flooding on life, health, and safety depend on several factors including severity of the e vent and
whether adequate warning time is provided to residents. Vulnerable populations are all populations residing or
located in the floodplain or downstream of dam failures that are incapable of escaping the area within the required
timeframe to reach safety. However, exposure should not be limited only to those who reside within a defined
hazard zone, but everyone who may be affected by a hazard event (e.g., people are considered at risk if they are
traveling in flooded areas, or their access to emergency services is compromised during an event). Flash floods
can be localized events that affect areas outside of the floodplain due to localized drainage issues and can directly
impact populations and comprise access to emergency services. The degree of that impact varies and is not
strictly measurable.
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-74
2022 Update
An estimated 103,507 people reside in the 1-percent annual chance event boundary, and 179,463 people within
the 0.2-percent annual chance flood boundary. These residents may be displaced by the flooding of their homes,
requiring them to seek temporary shelter with friends and family or in emergency shelters. Table 4-34 lists
population estimates within flood hazard zones in the County.
Table 4-34. Estimated Population Exposed to the Flood Hazard
Jurisdiction
Total
Population
1-Percent Chance Event 0.2-Percent Chance Event
Total Number
Percent of
Total Total Number Percent of Total
Bayou Vista (C) 1,763 1,763 100.0% 1,763 100.0%
Clear Lake Shores (C) 1,258 1,258 100.0% 1,258 100.0%
Dickinson (C) 20,847 13,938 66.9% 19,334 92.7%
Friendswood (C) 41,213 2,741 6.6% 7,431 18.0%
Hitchcock (C) 7,301 5,440 74.5% 7,254 99.4%
Jamaica Beach (C) 1,078 1,078 100.0% 1,078 100.0%
Kemah (C) 1,807 1,091 60.4% 1,692 93.6%
La Marque (C) 18,030 1,772 9.8% 11,775 65.3%
League City (C) 114,392 14,301 12.5% 41,106 35.9%
Santa Fe (C) 12,735 543 4.3% 2,112 16.6%
Tiki Island (V) 1,106 1,106 100.0% 1,106 100.0%
Galveston County
(Total)
350,682 103,507 29.5% 176,463 50.3%
Sources: American Community Survey 2019 (5-year estimates 2015-2019), FEMA 2018; February 16, 2018 FEMA Effective
DFIRM
Of the population exposed, the most vulnerable include the economically disadvantaged and the population over
age 65. Economically disadvantaged populations are more vulnerable because they are likely to evaluate their
risk and make decisions to evacuate based on net economic impacts to their families. The population over age
65 is also more vulnerable because available medical services may be disrupted, and they are more likely to seek
or need medical attention that may not be available due to isolation during a flood event. They also may have
more difficulty evacuating. Table 4-35 presents the estimated potential sheltering needs as a result of the 1-
percent and 0.2-percent flood events.
Table 4-35. Estimated Population Displaced or Seeking Short-Term Shelter from Flood Events
Jurisdiction
Total
Population
1-Percent Annual Chance Flood Event 0.2-Percent Annual Chance Flood Event
Displaced
Population
Persons Seeking
Short-Term Sheltering
Displaced
Population
Persons Seeking
Short-Term
Sheltering
Bayou Vista (C) 1,763 0 0 0 0
Clear Lake Shores (C) 1,258 70 7 102 9
Dickinson (C) 20,847 3,736 452 11,566 1,253
Friendswood (C) 41,213 2,838 1,061 6,123 1,237
Hitchcock (C) 7,301 241 59 4,590 700
Jamaica Beach (C) 1,078 0 0 27 2
Kemah (C) 1,807 0 0 1,131 229
La Marque (C) 18,030 708 106 8,241 742
League City (C) 114,392 5,555 1,608 31,547 4,946
Santa Fe (C) 12,735 661 189 2,456 431
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-75
2022 Update
Jurisdiction
Total
Population
1-Percent Annual Chance Flood Event 0.2-Percent Annual Chance Flood Event
Displaced
Population
Persons Seeking
Short-Term Sheltering
Displaced
Population
Persons Seeking
Short-Term
Sheltering
Tiki Island (V) 1,106 0 0 205 15
Galveston County
(Total)
350,682 17,125 4,447 100,532 14,409
Source: American Community Survey 2019 (5-year estimates 2015-2019), FEMA 2018; February 16, 2018 FEMA Effective DFIRM
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Total numbers of injuries and casualties resulting from typical riverine flooding are generally limited based on
advance weather forecasting, blockades, and warnings. Injuries and deaths generally are not anticipated if
proper warning and precautions occur. In contrast, warning time for dam failure events or flash flooding is
limited. These events are frequently associated with other natural hazard events such as earthquakes, landslides,
or severe weather, which limits their predictability and compounds the hazard. Populations without adequate
warning of the event are highly vulnerable to this hazard; this includes populations downstream of a dam failure
event that cannot evacuate within the allowable time frame. The population adversely affected by a dam failure
event can also include those beyond the disaster area that rely on the dam for providing potable water. Like
riverine flooding, economically disadvantaged populations and the elderly are more vulnerable to impacts from
a sudden dam failure event or flash flooding.
Cascading impacts may also include exposure to pathogens such as mold. After flood events, excess moisture
and standing water contribute to the growth of mold in buildings. Mold may present a health risk to building
occupants, especially those with already compromised immune systems such as infants, children, the elderly and
pregnant women. The degree of impact will vary and is not strictly measurable. Molds can grow in as short a
period as 24-48 hours in wet and damaged areas of buildings that have not been properly cleaned. Very small
mold spores can easily be inhaled, creating the potential for allergic reactions, asthma episodes, and other
respiratory problems. Buildings should be properly cleaned and dried out to safely prevent mold growth (CDC
2017).
Molds and mildews are not the only public health risk associated with flooding. Floodwaters can be contaminated
by pollutants such as sewage, human and animal feces, pesticides, fertilizers, oil, asbestos, and rusting building
materials. Common public health risks associated with flood events also include:
• Unsafe food
• Contaminated drinking and washing water and poor sanitation
• Mosquitos and animals
• Carbon monoxide poisoning
• Secondary hazards associated with re-entering/cleaning flooded structures
• Mental stress and fatigue (CDC 2012)
Current loss estimation models such as Hazus v4.2 cannot measure public health impacts. The best ways to
mitigate these impacts are to be aware that they can occur, educate the public on prevention, and be prepared to
deal with these vulnerabilities in responding to flood events.
Impact on General Building Stock
To assess potential impacts on buildings, both exposure (located in the hazard area) and estimated loss to the
exposed inventory generated by Hazus v4.2 were examined for the three flood scenarios. Table 4-36 and Table
4-37 summarizes the results.
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-76
2022 Update
Table 4-36. Estimated General Building Stock Exposure to a 1-Percent Annual Chance Flood Event
Jurisdiction
Total
Number
of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located in the Flood
Hazard Area
Number
of
Buildings
Located
in the
Hazard
Area
Percent of
Total
Total RCV of
Buildings
Located in the
Hazard Area
Percent
of Total
Bayou Vista (C) 1365 $445,354,087.33 1,365 100.0% $445,354,087 100.0%
Clear Lake Shores (C) 1155 $904,562,368.66 1,153 99.8% $724,937,594 80.1%
Dickinson (C) 10351 $6,601,710,645.63 6,848 66.2% $4,296,054,522 65.1%
Friendswood (C) 14891 $10,815,456,384.12 983 6.6% $698,448,414 6.5%
Hitchcock (C) 5452 $4,592,036,651.86 3,854 70.7% $2,857,796,355 62.2%
Jamaica Beach (C) 1291 $458,205,838.82 1,291 100.0% $458,205,839 100.0%
Kemah (C) 1634 $2,631,702,105.60 940 57.5% $1,977,207,949 75.1%
La Marque (C) 10749 $7,927,292,522.28 1,015 9.4% $593,214,455 7.5%
League City (C) 46742 $31,237,974,594.10 5,887 12.6% $4,443,465,559 14.2%
Santa Fe (C) 7942 $4,831,628,162.13 390 4.9% $225,325,480 4.7%
Tiki Island (V) 868 $365,209,145.44 868 100.0% $365,209,145 100.0%
Galveston County (Total) 209947 $166,321,604,688.46 81,490 38.8% $73,043,916,760 43.9%
Source: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021, FEMA 2018; February 16, 2018 FEMA Effective DFIRM
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County
Table 4-37. Estimated General Building Stock Exposure to a 0.2-Percent Annual Chance Flood Event
Jurisdiction
Total
Number
of
Buildings
Total
Replacement Cost
Value (RCV)
Estimated Building Stock Located in the Flood Hazard
Area
Number
of
Buildings
in
Hazard
Area
Percent of
Total
Total
Replacement
Cost Value of
Buildings in
Hazard Area
Percent
of Total
Bayou Vista (C) 1365 $445,354,087.33 1,365 100.0% $445,354,087 100.0%
Clear Lake Shores (C) 1155 $904,562,368.66 1,155 100.0% $904,562,369 100.0%
Dickinson (C) 10351 $6,601,710,645.63 9,656 93.3% $6,240,616,132 94.5%
Friendswood (C) 14891 $10,815,456,384.12 2,677 18.0% $2,128,680,168 19.7%
Hitchcock (C) 5452 $4,592,036,651.86 5,380 98.7% $4,453,984,059 97.0%
Jamaica Beach (C) 1291 $458,205,838.82 1,291 100.0% $458,205,839 100.0%
Kemah (C) 1634 $2,631,702,105.60 1,533 93.8% $2,582,447,999 98.1%
La Marque (C) 10749 $7,927,292,522.28 6,857 63.8% $4,355,120,524 54.9%
League City (C) 46742 $31,237,974,594.10 17,035 36.4% $12,600,904,732 40.3%
Santa Fe (C) 7942 $4,831,628,162.13 1,318 16.6% $687,674,130 14.2%
Tiki Island (V) 868 $365,209,145.44 868 100.0% $365,209,145 100.0%
Galveston County (Total) 209947 $ 166,321,604,688 124,067 59.1% $104,723,627,795 63.0%
Source: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021, FEMA 2018; February 16, 2018 FEMA Effective
DFIRM
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-77
2022 Update
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County
NFIP Statistics
A property is considered a repetitive loss (RL) property when there are “two or more losses reported which
were paid more than $1,000 for each loss. The two losses must be within 10 years of each other and be at
least 10 days apart. Only losses from (sic since) 1/1/1978 that are closed are considered. A severe repetitive
loss (SRL) property is defined as a residential property covered under an NFIP flood insurance policy, and
satisfying either of conditions 1 and 2, as well as condition 3 (Section 1361A of the National Flood Insurance
Act 42 United States Code 4102a):
1. “At least four NFIP claim payments for the property (including building and contents) over
$5,000 each have occurred, and the cumulative amount of such claims payments exceeded $20,000.
2. At least two separate claims payments for the property (building payments only) have occurred, and
the cumulative amount of the building portion of such claims exceeded the market value of the building.
3. For either of the above, at least two of the referenced claims must have occurred within any 10-year
period and must have occurred more than 10 days apart”.
Table 4-38 summarizes the NFIP policies, losses, and claims statistics in Galveston County. In total, 62,867
residents are NFIP policy holders in the County, and there have been 55,196 claims totaling over $2.3 billion.
These statistics show the economic benefits of participating in the NFIP to insure homes in flood hazard areas
of the County.
Table 4-38. NFIP Policies, Claims and Repetitive Loss Statistics
Jurisdiction
Total Policies (Direct +
Write Your Own)
Total Losses (Direct
+ Write Your Own)
Total Claims Paid (Direct +
Write Your Own)
Bayou Vista (C) 532 137 $3,425,622
Clear Lake Shores (C) 545 1,199 $26,600,777
Dickinson (C) 3,911 2,595 $239,101,802
Friendswood (C) 6,308 4,005 $255,175,550
Hitchcock (C) 1,089 1,461 $39,676,284
Jamaica Beach (C) 912 1,573 $22,541,508
Kemah (C) 634 1,350 $42,403,304
La Marque (C) 2,007 1,640 $32,414,112
League City (C) 19,704 5,375 $250,669,561
Santa Fe (C) 2,029 716 $37,010,820
Tiki Island (V) 443 640 $6,519,690
Galveston County (Total) 62,867 55,196 $2,395,581,821
Source: FEMA 2022
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the
County.
Impact on Critical Facilities
It is important to determine the critical facilities and infrastructure within the County that may be at risk to
flooding (riverine, dam failure, flash/stormwater flooding), and who may be impacted should damage occur.
Critical services during and after a flood event may not be available if critical facilities are directly damaged or
transportation routes to access these critical facilities are impacted. Roads that are blocked or damaged can
isolate residents and can prevent access throughout the planning area to many service providers needing to get
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-78
2022 Update
to vulnerable populations or to make repairs. Utilities such as overhead power, cable, and phone lines could also
be vulnerable due to utility poles damaged by standing water or the surge of water from a dam failure event.
Loss of these utilities could create additional isolation issues for the inundation zones.
Critical facility exposure to the flood hazard was examined. In addition, Hazus v4.2 was used to estimate the
flood loss potential to critical facilities exposed to the flood risk. Table 4-39 and Table 4-40 summarizes these
results.
Table 4-39. Critical Facility Types Located in the 1% Annual Chance Flood Hazard Area and Damages
Jurisdiction
Total Critical
Facilities Located
in Jurisdiction
Total Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline
Facilities Located in the 1-Percent Annual Chance
Flood Event Hazard Area
Critical
Facilities
Percent of
Total
Critical
Facilities Lifelines
Percent of
Total
Lifelines
Bayou Vista (C) 5 5 5 100.0% 5 100.0%
Clear Lake Shores (C) 24 24 22 91.7% 22 91.7%
Dickinson (C) 91 83 63 69.2% 59 71.1%
Friendswood (C) 96 82 20 20.8% 20 24.4%
Hitchcock (C) 214 212 143 66.8% 142 67.0%
Jamaica Beach (C) 11 11 11 100.0% 11 100.0%
Kemah (C) 15 14 12 80.0% 11 78.6%
La Marque (C) 121 107 30 24.8% 30 28.0%
League City (C) 321 283 94 29.3% 94 33.2%
Santa Fe (C) 135 128 9 6.7% 9 7.0%
Tiki Island (V) 7 7 7 100.0% 7 100.0%
Galveston County (Total) 2,437 2,317 1,346 55.2% 1,324 57.1%
Source: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021, FEMA 2018; February 16, 2018 FEMA Effective
DFIRM
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Table 4-40. Critical Facility Types Located in the 0.2% Annual Chance Flood Hazard Area and Damages
Jurisdiction
Total CFs
Located in
Jurisdiction
Total
Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline
Facilities Located in the 0.2-Percent
Annual Chance Flood Event Hazard Area
Critical
Facilities
Percent
of Total
Critical
Facilities Lifelines
Percent
of Total
Lifelines
Bayou Vista (C) 5 5 5 100.0% 5 100.0%
Clear Lake Shores (C) 24 24 24 100.0% 24 100.0%
Dickinson (C) 91 83 87 95.6% 79 95.2%
Friendswood (C) 96 82 30 31.3% 30 36.6%
Hitchcock (C) 214 212 207 96.7% 205 96.7%
Jamaica Beach (C) 11 11 11 100.0% 11 100.0%
Kemah (C) 15 14 15 100.0% 14 100.0%
La Marque (C) 121 107 74 61.2% 66 61.7%
4.3.6: Flood
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Jurisdiction
Total CFs
Located in
Jurisdiction
Total
Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline
Facilities Located in the 0.2-Percent
Annual Chance Flood Event Hazard Area
Critical
Facilities
Percent
of Total
Critical
Facilities Lifelines
Percent
of Total
Lifelines
League City (C) 321 283 161 50.2% 149 52.7%
Santa Fe (C) 135 128 33 24.4% 33 25.8%
Tiki Island (V) 7 7 7 100.0% 7 100.0%
Galveston County (Total) 2,437 2,317 1,748 71.7% 1,696 73.2%
Source: Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021, FEMA 2018; February 16, 2018 FEMA Effective
DFIRM
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County
Impact on the Economy
Flood events can significantly impact the local and regional economy. This includes but is not limited to general
building stock damages and associated tax loss, impacts to utilities and infrastructure, agricultural losses,
business interruption, and effects on tourism.
In areas that are directly flooded, renovations of commercial and industrial buildings may be necessary,
disrupting associated services. Refer to the section earlier which discusses direct impacts to buildings in the
County.
Flooding can cause extensive damage to public utilities and disruptions to delivery of services. Loss of power
and communications may occur and drinking water and wastewater treatment facilities may be temporarily out
of operation.
Debris management may also be a large expense after a flood event. Hazus v4.2 estimates the amount of
structural debris generated during a flood event. The model breaks down debris into three categories: (1) finishes
(dry wall, insulation, etc.); (2) structural (wood, brick, etc.); and (3) foundations (concrete slab and block, rebar,
etc.). These distinctions are necessary because of the different types of equipment needed to handle debris.
Table 4-41 and Table 4-42 summarize the Hazus v4.2 countywide debris estimates for the 1-percent and 0.2-
percent annual chance flood events. Please note that this table only estimates structural debris generated by
flooding and does not include non-structural debris or additional potential damage and debris possibly generated
by wind that may be associated with a flood event or storm that causes flooding.
Table 4-41. Estimated Debris Generated from a 1-Percent Chance Annual Flood
Jurisdiction
1-Percent Annual Chance Flood Event
Total
(tons)
Finish
(tons)
Structure
(tons)
Foundation
(tons)
Bayou Vista (C) 0 0 0 0
Clear Lake Shores (C) 4,030 710 1,689 1,630
Dickinson (C) 9,834 7,351 868 1,615
Friendswood (C) 22,367 11,295 5,162 5,910
Hitchcock (C) 4,113 1,269 1,835 1,009
Jamaica Beach (C) 0 0 0 0
Kemah (C) 0 0 0 0
La Marque (C) 2,745 1,613 603 529
League City (C) 58,291 20,090 17,576 20,626
Santa Fe (C) 2,195 1,524 312 360
Tiki Island (V) 0 0 0 0
Galveston County (Total) 141,754 58,635 40,584 42,536
4.3.6: Flood
Galveston County, TX | Hazard Mitigation Plan 4-80
2022 Update
Source: Hazus v4.2
*Calculated using a Census block level, general building stock (GBS) analysis in Hazus 4.2 SP03
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Table 4-42. Estimated Debris Generated from a 0.2-Percent Chance Annual Flood
Jurisdiction
0.2-Percent Annual Chance Flood Event
Total
(tons)
Finish
(tons)
Structure
(tons)
Foundation
(tons)
Bayou Vista (C) 0 0 0 0
Clear Lake Shores (C) 13,729 2,523 6,207 5,000
Dickinson (C) 23,199 17,746 2,263 3,190
Friendswood (C) 24,423 13,370 5,154 5,898
Hitchcock (C) 16,060 8,858 3,996 3,206
Jamaica Beach (C) 3,260 785 1,481 994
Kemah (C) 79,700 13,835 44,548 21,317
La Marque (C) 15,049 12,425 1,382 1,242
League City (C) 120,544 61,619 27,403 31,522
Santa Fe (C) 3,792 2,812 436 545
Tiki Island (V) 15,246 3,288 6,848 5,110
Galveston County (Total) 681,783 260,427 244,604 176,753
Source: Hazus v4.2
*Calculated using a Census block level, general building stock (GBS) analysis in Hazus 4.2 SP03
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on the Environment
Floodplains serve beneficial and natural functions on ecological, environmental, social, and economic levels.
Areas in the floodplain that typically provide these natural functions and benefits are wetlands, riparian areas,
sensitive areas, and habitats for rare and endangered species. Floods, however, can also lead to negative impacts
on the environment. Disruption of natural systems and the benefits they provide can have long-term
consequences for entire regions. According to FEMA, well-known, water-related functions of floodplains
include the following:
• Natural flood and erosion control
• Provide flood storage and conveyance
• Reduce flood velocities
• Reduce flood peaks
• Reduce sedimentation
• Surface water quality maintenance
• Process organic wastes
• Moderate temperatures of water
• Groundwater recharge
• Filter nutrients and impurities from runoff
• Promote infiltration and aquifer recharge
• Reduce frequency and duration of low-surface
flows
Future Changes that May Impact Vulnerability
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change
Projected Development
Any areas of growth could be impacted by the flood hazard if located in the floodplain. The Flood Damage
Prevention Ordinance regulates not only how land in designated floodplain areas may be used or altered, but the
location and types of structures that are permitted in those areas as well as the specifications to which they must
4.3.7: Hail
Galveston County, TX | Hazard Mitigation Plan 4-81
2022 Update
build. All structures, including residential and commercial properties, manufactured homes, and the
developments of subdivisions are regulated.
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2019 American Community Survey estimated population of 350,682. The population of the County is expected
to increase over the next few years. The increase in population will expose more people to the flood hazard,
especially those living in and around flood hazard areas.
Climate Change
Increases in precipitation may alter and expand the floodplain boundaries and runoff patterns, resulting in the
exposure of populations, buildings, and critical facilities and infrastructure that were previously outside the
floodplain. This increase in exposure would result in an increased risk to life and health, an increase in structural
losses, a diversion of additional resources to response and recovery efforts, and an increase in business closures
affected by future flooding events due to loss of service or access.
Change of Vulnerability Since the 2017 HMP
Galveston County continues to be vulnerable to flood storms. While flood models were run for the 2017 HMP,
the population has increased since then. Furthermore, the vulnerability of the building stock was not assessed.
The 2022 updated therefore provides more accurate estimated exposure and potential losses due to flooding for
Galveston County.
4.3.7 Hail
The following section provides the hazard profile and vulnerability assessment for the hail hazard in Galveston
County.
Profile
Hazard Description
Hail forms inside a thunderstorm where there are strong updrafts of warm air and downdrafts of cold water. If a
water droplet is picked up by the updrafts, it can be carried well above the freezing level. Water droplets freeze
when temperatures reach 32 °F or colder. As the frozen droplet begins to fall, it might thaw as it moves into
warmer air toward the bottom of the thunderstorm, or the droplet might be picked up again by another updraft
and carried back into the cold air to re-freeze. With each trip above and below the freezing level, the frozen
droplet adds another layer of ice. The frozen droplet, with many layers of ice, falls to the ground as hail. Figure
4-22 shows the hail formation process. Most hail is small and typically less than two inches in diameter (NOAA
NWS 2009)
Section 4.3.7 - Hail
Galveston County, TX | Hazard Mitigation Plan 4-82
2022 Update
Figure 4-22 Hail Formation
Source: Encyclopedia Britannica 2012
Figure 4-23 shows the annual frequency of hailstorms in the United States as recorded from 2003 to 2012.
Hailstorms have been observed in almost every location where thunderstorms occur throughout the United
States. They are most frequent in the southern and central plain states where the climate produces violent
thunderstorms. The figure shows that Galveston County experiences between one and five severe hail days each
year. Severe hail day is defined as a day with at least one report of one-inch or more hail within 25 miles.
Location
All of Galveston County is exposed and vulnerable to hail.
Extent
The severity of hail is measured by duration, hail size, and geographic extent. Most hail stones from hail events
are made up of variety of sizes. Only the very largest hail stones pose serious risk to people, if exposed. The size
of hail is estimated by comparing it to a known object. Table 4-43 shows the different sizes of hail and the
comparison to real-world objects.
Section 4.3.7 - Hail
Galveston County, TX | Hazard Mitigation Plan 4-83
2022 Update
Figure 4-23. Severe Hail Days Per Year from 2003-2012
Source: SPC 2020
Table 4-43 Hail Size
Size Inches in Diameter
Pea 0.25 inch
Small Marble 0.50 inch
Penny or Large Marble 0.75 inch
Nickel 0.875 inch
Quarter 1.0 inch
Ping-Pong Ball 1.5 inches
Golf Ball 1.75 inches
Hen Egg 2.5 inches
Tennis Ball 2.75 inches
Baseball 3.0 inches
Teacup 4.0 inches
Grapefruit inches
Source: NOAA 2021
The Tornado and Storm Research Organisation (TORRO) Hailstorm Intensity Scale (H0 to H10) relates typical
damage and hail sizes.
Table 4-44. TORRO Hailstorm Intensity Scale
TORRO Hailstorm
Intensity Scale
Intensity Category Typical Hail
Diameter (mm)
Typical Damage Impacts
H0 Hard Hail 5 No damage
H1 Potentially Damaging 5-15 Slight general damage to plants, crops
H2 Significant 10-20 Significant damage to fruit, crops, vegetation
Section 4.3.7 - Hail
Galveston County, TX | Hazard Mitigation Plan 4-84
2022 Update
TORRO Hailstorm
Intensity Scale
Intensity Category Typical Hail
Diameter (mm)
Typical Damage Impacts
H3 Severe 20-30 Severe damage to fruit and crops, damage to glass
and plastic structures, paint and wood scored
H4 Severe 25-40 Widespread glass damage, vehicle bodywork damage
H5 Destructive 30-50 Wholesale destruction of glass, damage to tiled roofs,
significant risk of injuries
H6 Destructive 40-60 Bodywork of grounded aircraft dented; brick walls
pitted
H7 Destructive 50-75 Severe roof damage, risk of serious injuries
H8 Destructive 60-90 (Severest recorded in the British Isles) Severe
damage to aircraft bodywork
H9 Super Hailstorms 75-100 Extensive structural damage. Risk of severe or even
fatal injuries to persons caught in the open
H10 Super Hailstorms >100 Extensive structural damage. Risk of severe or even
fatal injuries to persons caught in the open
Source: TORRO 2021
Worst-Case Scenario
Hail usually occurs with a thunderstorms. A worst-case scenario would be a severe thunderstorm producing
large hail (quarter-size [1-inch] and larger). This event would be a H3 (severe) hailstorm event on the TORRO
intensity scale. An event like this can cause severe damage to fruit and crops, damage to glass and plastic
structures, paint and wood scored, and damage to roofs. The aftermath of a severe hail event could lead to
millions of dollars in damages.
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
hail events in Galveston County. According to the NOAA-NCEI Storm Events Database, Galveston County has
been impacted by 120 hail events between 1950 and 2020 that caused more than $3 million in property damage
(refer to Table 4-45).
Table 4-45. Hail Events in Galveston County, 1950-2021
Hazard Type
Number of
Occurrences
Between 1957
and 2020 Total Fatalities Total Injuries
Total Property
Damage ($)
Total Crop
Damage ($)
Hail 120 0 0 $3,022,510 $0
Source: NOAA-NCEI 2021
Note: Due to limitations in data, not all thunderstorm wind events occurring between 1950 and 2021 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated
Between 1953 and 2021, the State of Texas was included in five hail-related major disaster (DR) or emergencies
(EM) declarations. Of those declarations, Galveston County was not included in any of those declarations. This
HMP update includes known hail events that have impacted Galveston County between 2016 and 2021. These
events are shown in Table 4-46. The events listed in Table 4-46 represent only those that were reported to the
NOAA-NCEI Storm Events Database, FEMA, and the 2017 Galveston County HMP, and may not represent all
hail events that have occurred in the County. For events prior to 2016, refer to the 2017 Galveston County HMP.
Table 4-46. Hail Events in Galveston County, 2016 to 2021
Date(s)
of Event
Event
Type Magnitude Fatalities Injuries Damages Event Details*
January 8,
2016 Hail 0.75 - - $0 Penny sized hail occurred to the northwest of
La Marque.
Section 4.3.7 - Hail
Galveston County, TX | Hazard Mitigation Plan 4-85
2022 Update
Date(s)
of Event
Event
Type Magnitude Fatalities Injuries Damages Event Details*
April 13,
2016 Hail 1.0 - - $0 The quarter size hail was reported in
Friendswood.
April 13,
2016 Hail 0.75 - - $0 The dime size hail was reported in League City.
May 2,
2016 Hail 1.0 - - $0 Quarter size hail was reported near the
intersection of 67th Street and Heards Lane.
February
26, 2019 Hail 0.88 - - $0 There were various reports of pea to nickel
sized hail.
May 28,
2020 Hail 0.7 - - $10 Dime sized hail was observed in Texas City.
January 6,
2021 Hail 1.0 - - -
Severe hail (1 in.) was observed by a member
of the public as a squall line moved through
Galveston County.
Source(s): FEMA 2021; NOAA-NCEI 2021; Galveston County 2017
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact
information may vary and has been summarized in the above table
FEMA Federal Emergency Management Agency
HMP Hazard Mitigation Plan
NCEI National Centers for Environmental Information
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016). While predicting the trends of hail as a result of
climate change is difficult, it is anticipated that more frequent and intense will occur. Some of these storms can
bring hail.
Probability of Future Occurrences
Table 4-47 summarizes data regarding the probability of occurrences of hail events in Galveston County based
on the historic record. The information used to calculate the probability of occurrences is based on the NOAA-
NCEI Storm Events Database, FEMA, and the 2017 Galveston HMP, including only those events that identified
hail occurring in the County.
Table 4-47. Probability of Future Occurrence of Hail Events
Hazard Type
Number of Occurrences Between 1954
and 2021
% chance of occurrence in any
given year
Hail 120 100%
Source: NOAA-NCEI 2021; FEMA 2021; Galveston HMP 2017
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected hail events since
1968. Due to limitations in data, not all hail events occurring between 1954 and 1996 are accounted for in the tally of occurrences. As a
result, the number of hazard occurrences is underestimated.
Galveston County is expected to continue experiencing the direct and indirect impacts of hail events each year.
The County experienced 120 hail incidents in 67 years, giving the County a 100% chance of being impacted by
a hail incident in any given year. Based on historical records and input from the Steering Committee, the
probability of occurrence for hail events in the County is considered frequent (100% chance occurring; occurs
multiple times a year). Refer to Section 4.4 for additional information on the hazard ranking methodology and
probability criteria.
Section 4.3.7 - Hail
Galveston County, TX | Hazard Mitigation Plan 4-86
2022 Update
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the hail hazard; therefore, all assets within the County
(population, structures, critical facilities, and lifelines), as described in Section 3 (County Profile), are potentially
vulnerable to a hail event. The following text evaluates and estimates the potential impact of the hail hazard in
the County.
Impact on Life, Health and Safety
The impact of hail events on life, health, and safety is dependent upon several factors including the severity of the
event and whether adequate warning time was provided to residents. The entire population of Galveston County
(350,682) is assumed to be exposed to this hazard (U.S. Census 2017 ACS 5-Year Population Estimate).
People are vulnerable to the effects of hail events, including injuries, power outages, impacts on transportation
routes, damage to homes, and damage to vehicles. First responders are also at risk of being injured during a
significant hail event if they are responding to an incident. People located outdoors (e.g. recreational activities,
farming, emergency responders) are considered most vulnerable to hailstorms because there is little to no
warning time, and shelter might not be available. Moving to a lower risk location can decrease a person’s
vulnerability.
Impact on General Building Stock
Depending on the size of the hail and severity of the storm, the County could see damage from hail impacting
structures. While damage to the building stock is possible as a result of hail, it is difficult to estimate and would
not have as wide of an impact as a high wind or tornado event.
Impact on Critical Facilities
All critical facilities in Galveston County are vulnerable to being affected by hail events.
Impact on Economy
Hail-producing severe storms impact the economy; impacts include loss of business function, damage to
inventory, relocation costs, wage loss, and rental loss due to the repair or replacement of buildings. Additionally,
vehicles parked outdoors are vulnerable to hail damage and could increase economic impacts of a storm. The
2016 HMP predicted that annual property losses due to hail would amount to $31,554 (Galveston County 2016
HMP).
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Any areas of growth could be potentially impacted by the hail hazard because the entire County is exposed and
vulnerable.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-87
2022 Update
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2015-2019 American Community Survey estimated population of 350,682. The population of the County is
expected to further increase over the next few years. The increase in population will expose more people to the
hail hazard.
Climate Change
The entire State of Texas is projected to experience an increase in the frequency and severity of extreme storms
and rainfall. Major clusters of summertime thunderstorms in North America will grow larger, more intense, and
more frequent later this century in a changing climate, unleashing far more rain and posing a greater threat of
flooding across wide areas (UCAR 2017). Section 4.3.7 (Flood) provides a discussion related to the impact of
climate change due to increases in rainfall. An increase in storms will produce more wind events and can increase
tornado activity (refer to Section 4.3.3 [Tornadoes]). With an increased likelihood of strong storms, all of the
County’s assets will experience additional risk for losses as a result of hail-producing storm events.
Changes in Vulnerability Since the 2017 HMP
Galveston County’s population increased since the last plan; increasing the number of people impacted during a
hail event. Therefore, the entire County remains vulnerable to hail events.
4.3.8 Hurricane and Tropical Storm
The following section provides the hazard profile and vulnerability assessment for the hurricane and tropical
storm hazard in Galveston County.
Profile
Hazard Description
Tropical cyclones are fueled by a different heat mechanism than other cyclonic windstorms, such as Nor’easters
and polar lows. The characteristic that separates tropical storms from other cyclonic systems is that at any height
in the atmosphere, the center of a tropical storm will be warmer than its surroundings, a phenomenon called
warm core storm systems (NOAA n.d.). Tropical cyclones strengthen when water evaporated from the ocean is
released as the saturated air rises, resulting in condensation of water vapor contained in the moist air. Tropical
cyclones begin as disturbed areas of weather, often referred to as tropical waves. As the storm organizes, it is
designated as a tropical depression.
A tropical storm system is characterized by a low-pressure center and numerous thunderstorms that produce
strong winds of 39 to 73 mph and heavy rain. A hurricane is a tropical storm that attains hurricane status when
its wind speed reaches 74 mph or higher. Tropical systems can develop in the Atlantic between the Lesser
Antilles and the African coast or in the warm tropical waters of the Caribbean Sea and Gulf of Mexico. These
storms can move up the Atlantic coast of the United States, impacting the eastern seaboard, or move into the
United States through the states along the Gulf Coast, bringing wind and rain as far north as New England before
moving eastward offshore.
Location
Similar to that of severe weather events (e.g. tornadoes, thunderstorms), hurricanes and tropical storms do not
have any specific geographic boundary and can occur anywhere in the County. According to the FEMA Winds
Zones of the United States map, Galveston County is located in Wind Zone III, where wind speeds can reach up
to 200 mph. Additionally, the County is located in the hurricane-susceptible region. Figure 4-24 illustrates wind
zones across the United States, which indicate the impacts of the strength and frequency of wind activity per
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-88
2022 Update
region. The information on the figure is based on 70 years of tornado data and 160 years of hurricane data
collected by FEMA (FEMA 2021).
Figure 4-24. Wind Zones in the United States
Source: FEMA 2021
Note: The blue circle indicates the approximate location of Galveston County.
Extent
The extent of a hurricane or tropical storm is commonly categorized in accordance with the Saffir-Simpson
Hurricane Wind Scale, which assigns a designation of tropical storm for storms with sustained wind speeds
below 74 mph and a hurricane category rating of 1–5 based on a hurricane’s increasing sustained wind speed.
This scale estimates potential property damage. Hurricanes reaching Category 3 and higher are considered major
hurricanes because of their potential for significant loss of life and damage. Tropical Storms and Category 1 and
2 storms are still dangerous and require preventative measures (NWS NOAA n.d.). Figure 4-25 presents this
scale, which is used to estimate the potential property damage and flooding expected when a hurricane makes
landfall.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-89
2022 Update
Figure 4-25. The Saffir-Simpson Scale
Source: Disaster Readiness Portal 2020
The NWS issues hurricane and tropical storm watches and warnings. These watches and warnings are issued or
will remain in effect after a tropical cyclone becomes post-tropical, when such a storm poses a significant threat
to life and property. The NWS allows the National Hurricane Center (NHC) to issue advisories during the post-
tropical stage. The following are the definitions of the watches and warnings:
• Hurricane/Typhoon Warning is issued when sustained winds of 74 mph or higher are expected
somewhere within the specified area in association with a tropical, subtropical, or post-tropical cyclone.
Because hurricane preparedness activities become difficult once winds reach tropical storm force, the
warning is issued 36 hours in advance of the anticipated onset of tropical storm-force winds. The
warning can remain in effect when dangerously high water or combination of dangerously high water
and waves continue, even though winds may be less than hurricane force.
• Hurricane Watch is issued when sustained winds of 74 mph or higher are possible within the specified
area in association with a tropical, subtropical, or post-tropical cyclone. Because hurricane preparedness
activities become difficult once winds reach tropical storm force, the hurricane watch is issued 48 hours
prior to the anticipated onset of tropical storm-force winds.
• Tropical Storm Warning is issued when sustained winds of 39 to 73 mph are expected somewhere within
the specified area within 36 hours in association with a tropical, subtropical, or post-tropical storm.
• Tropical Storm Watch is issued when sustained winds of 39 to 73 mph are possible within the specified
area within 48 hours in association with a tropical, sub-tropical, or post-tropical storm (NHC NOAA
2010).
Mean Return Period
In evaluating the potential for hazard events of a given magnitude, a mean return period (MRP) is often used.
The MRP provides an estimate of the magnitude of an event that may occur within any given year based on past
recorded events. The MRP is the average period of time, in years, between occurrences of a particular hazard
event, equal to the inverse of the annual frequency of exceedance.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-90
2022 Update
Peak wind speed projections were generated using Hazus v5.0. Hazus v5.0 estimated the maximum 3-second
gust wind speeds for Galveston County:
• 100-year MRP – between 111 and 129 mph (Category 3 Hurricane)
• 500-year MRP – between 130 and 156 mph (Category 4 Hurricane).
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-91
2022 Update
Figure 4-26. Wind Speeds for the 100-Year MRP Event
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-92
2022 Update
Figure 4-27. Wind Speeds for the 500-Year MRP Event
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-93
2022 Update
Worst-Case Scenario
A category 4 hurricane would be the worst-case scenario hurricane for the County. A storm of this magnitude
could cause over $22 billion in building damages, displacing 25,021 households, forcing 16,068 people to seek
short-term housing, and causing over 42,000 tons of debris. The extreme winds associated with a category 4
(speeds between 130 and 156 mph) would cause catastrophic damages, leading to downed trees, downed power
lines, widespread power outages, significant damage to buildings and infrastructure, and limited access to areas
of the County. Heavy rains from a hurricane could lead to significant flooding and associated damages.
Additionally, storm surge associated with a category 4 hurricane would lead to potentially damaging over
170,000 buildings and over $138 billion in damages. Over 1,800 critical facilities/lifelines would be exposed
and vulnerable as well.
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
hurricanes and tropical storms in Galveston County. Between 1953 and 2020, FEMA included the State of Texas
in 29 hurricane-related major disaster (DR) or emergency (EM) declarations. Generally, these disasters cover a
wide region of the State; therefore, they may have impacted many counties. Galveston County was included in
14 of these hurricane-related declarations; refer to Table 4-48.
Table 4-48 Hurricane-Related FEMA Declarations for Galveston County, 1953 to 2021
FEMA Declaration
Number Date(s) of Event Incident Type Incident Title
DR-689 August 18-20, 1983 Hurricane Hurricane Alicia
DR-1239 August 22-31, 1998 Severe Storm Tropical Storm Charley
DR-1245 September 9-October 5, 1998 Severe Storm Tropical Storm Frances
DR-1379 June 5-20, 2001 Coastal Storm Tropical Storm Allison
DR-1434 September 6-30, 2002 Coastal Storm Tropical Storm Fay
DR-1479 July 15-28, 2003 Hurricane Hurricane Claudette
EM-3261 and DR-1606 September 20-October 14, 2005 Hurricane Hurricane Rita
EM-3277 August 17-September 5, 2007 Hurricane Hurricane Dean
EM-3290 August 27-September 7, 2008 Hurricane Hurricane Gustav
EM-3294 and DR-1791 September 7-October 2, 2008 Hurricane Hurricane Ike
DR-4332 August 23-September 15, 2017 Hurricane Hurricane Harvey
EM-3530 July 25-31, 2020 Hurricane Hurricane Hanna
EM-3540 August 23-27, 2020 Hurricane Tropical Storms Marco and Laura
DR-4572 August 23-27, 2020 Hurricane Hurricane Laura
Source: FEMA 2021
Figure 4-28 from the NOAA Historical Hurricane Tracker illustrates the tracks of storms between 1950 and 2020
within 60 nautical miles of Galveston County. NOAA showed 45 hurricanes or tropical storms being tracked
within 60 nautical miles of the County. As the figure depicts, the County is frequently impacted by hurricanes,
tropical storms, and tropical depressions.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-94
2022 Update
Figure 4-28 Historical Hurricane Tracks within 65 nautical miles of Galveston County, 1950 to 2020
Source: NOAA 2021
Note: Category refers to tropical cyclone strength.
This HMP update includes known hurricane and tropical storm events that have impacted Galveston County
between 2016 and 2021. These events are shown in Table 4-49. The events listed in Table 4-49 represent only
those that were reported to the NOAA-NCEI Storm Events Database, FEMA, and the 2017 Galveston County
HMP, and may not represent all hurricane and tropical storm events that have occurred since 2016. For events
prior to 2016, refer to the 2017 Galveston County HMP.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-95
2022 Update
Table 4-49. Hurricane and Tropical Storm Events in Galveston County, 2016 to 2021
Dates of Event Event Type
FEMA
Declaration
Number
(if
applicable)
County
Designated? Fatalities Injuries Damages Event Details*
June 21-22, 2017 Tropical
Storm Cindy N/A N/A - - -
Water and debris covered a low-lying section of Highway 87
near its intersection with Highway 124 which is an area that is
especially vulnerable to coastal flooding. Elsewhere, channels
were elevated around Jamaica Beach and other west end
communities of Galveston Island, but there was little impact.
August/September
2017
Hurricane
Harvey DR-4332 Yes 3 - $10 billion
Harvey made landfall as a category 4 hurricane near Rockport,
Texas during the evening of August 25th. Numerous roads were
flooded and impassable across northern and western Galveston
County. There were numerous water rescues across western and
central Galveston County. Flood waters completely inundated
hundreds to thousands of homes and businesses in League City,
Dickinson, and Santa Fe. Approximately 7,000 homes and 125
businesses were impacted by flood waters across the county.
Clear Creek measured record levels that lead to the widespread
flooding throughout Friendswood and League City. Major
flooding occurred along the Dickinson Bayou; from Cemetery
Road to east of Highway 3 along FM 517. Flood waters
inundated sections of Interstate 45, Bay Area Boulevard, FM
528, FM 518 and numerous primary and secondary county roads.
July 25-31, 2020 Hurricane
Hanna EM-3530 Yes - - - -
August 23-27,
2020
Tropical
Storms
Marco and
Laura
EM-3540 Yes - - -
Hurricane Laura made landfall along the southwest Louisiana
coast. The hurricane brought high surf, elevated tides and some
winds and wind gusts to tropical storm force along the SE Texas
coast. Period of storm surge flooding and high surf from August
26th through 27th leading to flooding of low lying areas and
roads. Beach erosion on Gulf side. Tide gauges measured tides 3
to 4 feet above MHHW. Bolivar Peninsula and Galveston Island,
including Jamaica Beach, with multiple roads closed.
August 23-27,
2020
Hurricane
Laura DR-4572 Yes - - -
October 8-9, 2020 Hurricane
Delta N/A N/A - - -
Hurricane Delta produced a long duration of sustained tropical
storm force winds across coastal areas. Delta also produced high
surf and elevated tides leading to mainly minor coastal flooding
along Gulf facing beaches and around Galveston Bay.
Source(s): FEMA 2021; NOAA-NCEI 2021; Galveston County HMP 2017
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact information may vary and has been summarized in the above table
- Not reported/not available
FEMA Federal Emergency Management Agency
HMP Hazard Mitigation Plan
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-96
2022 Update
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016). Major clusters of summertime storms in North
America will grow larger, more intense, and more frequent later this century in a changing climate, leading to
increased rainfall and posing a greater threat of flooding across wide areas (UCAR 2017).
Probability of Future Occurrences
Using the NOAA-NCEI database, NWS, FEMA, and the 2017 Galveston County HMP, Table 4-50 summarizes
data regarding the probability of occurrences of hurricane and tropical storm events in Galveston County based
on the historic record. It should be noted that many of these events impact a region. The information used to
calculate the probability of occurrences is based on the NWS’s Historic Hurricane Tracker and includes events
that were tracked within 60 nautical miles of the County.
Table 4-50. Probability of Future Occurrence of Hurricane/Tropical Storm Events
Hazard Type
Number of Occurrences Between
1954 and 2021*
% chance of occurrence in any
given year
Tropical Storms* 36 52.9%
Hurricanes
(Categories 1 and 2)* 12 17.6%
Major Hurricanes (Categories 3, 4, and 5)* 5 7.3%
TOTAL* 45 66.1%
Source: NOAA 2021
Note: * Individual storm category may have changed during the event, therefore the number of occurrences for each storm category will be
greater than the total number of individual storms.
Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected hurricane events
since 1968. Due to limitations in data, not all hurricane events occurring between 1954 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated.
Galveston County is expected to continue experiencing the direct and indirect impacts of hurricanes and tropical
storms each year. Based on historical records and input from the Steering Committee, the probability of
occurrence for hurricanes and tropical storm events in the County is considered occasional (between 10 and
100% annual chance of occurring). Refer to Section 4.4 for additional information on the hazard ranking
methodology and probability criteria.
Vulnerability Assessment
A probabilistic assessment was conducted for the 100- and 500-year MRPs through a Level 2 analysis in Hazus
to analyze the wind hazard associated with hurricanes and tropical storms and provide a range of loss estimates
due to wind impacts. Storm surge was also assessed using 2014 SLOSH (Sea, Lake, and Overland Surges from
Hurricanes) data from NOAA’s National Hurricane Center. Refer to Section 4.1 (Methodology and Tools) for
additional details on the methodology used to assess hurricane and tropical storm risk.
Impact on Life, Health and Safety
The impact of hurricanes and tropical storms on life, health, and safety is dependent upon several factors
including the severity of the event and whether or not adequate warning time was provided to residents. All
Galveston County residents are exposed to the hurricane storm and tropical storm hazard; however 18.9-percent,
36.8-percent, 60.1-percent, and 75.8-percent of the population is exposed to the SLOSH Category 1, Category
2, Category 3, and Category 4 inundation areas, respectively (2019 American Community Survey 5-year
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-97
2022 Update
Estimate). Table 4-51 for a summary of the number of persons exposed to the SLOSH Categories 1 through 4
by jurisdiction. Overall, the Cities of Clear Lake Shores and Dickinson have the great number of persons
exposed to the SLOSH Category 4 inundation areas.
Research has shown that some populations, while they may not have more hazard exposure, may experience
exacerbated impacts and prolonged recovery if/when impacted. This is due to many factors including their
physical and financial ability to react or respond during a hazard. Economically disadvantaged populations are
vulnerable because they are likely to evaluate their risk and make decisions based on the major economic impact
to their family and may not have funds to evacuate. The population over the age of 65 is also vulnerable and,
physically, they may have more difficulty evacuating. Additionally, the elderly are considered vulnerable
because they require extra time or outside assistance during evacuations and are more likely to seek or need
medical attention which may not be available due to isolation during a storm event. According to the 5-year
population estimates from the American Community Survey, Galveston County has a total of 37,264 persons
living in poverty and 46,103 over the age of 65 years old. Please refer to Section 3 (County Profile) for the
statistics of these populations.
Residents may be displaced or require temporary to long-term sheltering. In addition, downed trees, damaged
buildings, and debris carried by high winds can lead to injury or loss of life. Socially vulnerable populations are
most susceptible, based on a number of factors including their physical and financial ability to react or respond
during a hazard and the location and construction quality of their housing. Hazus estimates that 5,769 and 25,021
households will be displaced during the 100-year and 500-year MRP hurricane wind events, respectively. Hazus
also estimates that 3,725 and 16,068 persons will be seeking short-term shelter during the 100-year and 500-year
MRP hurricane wind events, respectively. Refer to Table 4-52 for a summary of the displaced households by
jurisdiction. Please note that estimates are only based on wind speed and do not account for sheltering needs
associated with flooding and storm surge that may accompany hurricane and tropical storm events.
Table 4-51. Estimated Population Exposed to the Hurricane Storm Surge SLOSH Category 1 through
Category 4 Hurricane Inundation Hazard Areas
Jurisdiction
Total
Population
(American
Community
Survey
2015-2019)
Number of Persons Located in the SLOSH Categories 1-4 Storm Surge Hazard Area
Storm Surge
Category 1
Storm Surge
Category 2
Storm Surge
Category 3
Storm Surge
Category 4
Number
of
Persons
Percent
of
Total
Number
of
Persons
Percent
of
Total
Number
of
Persons
Percent
of
Total
Number
of
Persons
Percent
of
Total
Bayou Vista (C) 1,763 1,702 96.6% 1,712 97.1% 1,710 97.0% 1,710 97.0%
Clear Lake Shores (C) 1,258 265 21.1% 1,250 99.3% 1,250 99.3% 1,252 99.5%
Dickinson (C) 20,847 595 2.9% 5,676 27.2% 19,349 92.8% 20,788 99.7%
Friendswood (C) 41,213 0 0.0% 108 0.3% 1,334 3.2% 6,721 16.3%
Hitchcock (C) 7,301 252 3.4% 5,259 72.0% 7,145 97.9% 7,254 99.4%
Jamaica Beach (C) 1,078 908 84.2% 1,015 94.2% 1,016 94.3% 1,007 93.4%
Kemah (C) 1,807 79 4.4% 569 31.5% 1,756 97.2% 1,771 98.0%
La Marque (C) 18,030 10,211 56.6% 10,816 60.0% 14,845 82.3% 17,548 97.3%
League City (C) 114,392 757 0.7% 11,013 9.6% 53,474 46.7% 86,750 75.8%
Santa Fe (C) 12,735 0 0.0% 4 0.0% 961 7.5% 3,075 24.1%
Tiki Island (V) 1,106 808 73.1% 899 81.3% 899 81.3% 899 81.3%
Galveston County (Total) 350,682 66,290 18.9% 129,076 36.8% 210,755 60.1% 265,843 75.8%
Source: NOAA 2014
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-98
2022 Update
Table 4-52. Estimated Hurricane Impact on Persons and Households
Jurisdiction
100-Year Mean Return Period
Hurricane 500-Year Mean Return Period Hurricane
Displaced
Households
Persons Seeking
Short-Term
Sheltering
Displaced
Households
Persons Seeking Short-Term
Sheltering
Bayou Vista (C) 36 15 125 52
Clear Lake Shores (C) 52 21 231 94
Dickinson (C) 284 207 1,458 1,054
Friendswood (C) 270 145 1,410 756
Hitchcock (C) 88 62 409 286
Jamaica Beach (C) 9 4 30 13
Kemah (C) 72 44 236 139
La Marque (C) 239 164 1,137 790
League City (C) 1,152 638 6,500 3,697
Santa Fe (C) 218 130 1,042 618
Tiki Island (V) 23 10 80 33
Galveston County
(Total)
5,769 3,725 25,021 16,068
Source: American Community Survey 2019 (5-year estimates 2015-2019), Hazus v4.2
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on General Building Stock
To estimate potential building exposure, the SLOSH inundation zones were overlaid upon the building stock
created for Galveston County. The estimated total number of buildings and replacement cost value located in
Categories 1 through 4 SLOSH inundation zones are summarized in Table 4-53 through Table 4-54 by
municipality. Overall, 50,086, 98,585, 144,078, and 170,325 buildings are exposed to the SLOSH Category 1,
Category 2, Category 3, and Category 4 inundation hazard areas, respectively. U p to 81.1-percent of the total
building stock in the County is exposed to the Category 4 inundation area, which is equal to approximately
$138.6 billion.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-99
2022 Update
Table 4-53. Number of Buildings in the SLOSH Category 1 through 2 Hurricane Inundation Hazard Areas
Jurisdiction
Total Number of
Buildings
Total Replacement Cost
Value (RCV)
Storm Surge Category 1 Storm Surge Category 2
Number of
Buildings
Percent of
Total
Total Replacement
Cost Value
Percent of
Total
Number of
Buildings
Percent of
Total
Total Replacement
Cost Value
Percent of
Total
Bayou Vista (C) 1365 $445,354,087.33 1,317 96.5% $424,749,186 95.4% 1,324 97.0% $425,921,023 95.6%
Clear Lake Shores (C) 1155 $904,562,368.66 274 23.7% $223,767,630 24.7% 1,144 99.0% $695,917,340 76.9%
Dickinson (C) 10351 $6,601,710,645.63 288 2.8% $171,527,463 2.6% 2,686 25.9% $1,555,280,586 23.6%
Friendswood (C) 14891 $10,815,456,384.12 0 0.0% $0 0.0% 38 0.3% $17,305,383 0.2%
Hitchcock (C) 5452 $4,592,036,651.86 181 3.3% $145,732,443 3.2% 3,713 68.1% $2,617,513,474 57.0%
Jamaica Beach (C) 1291 $458,205,838.82 1,076 83.3% $365,369,401 79.7% 1,217 94.3% $433,145,729 94.5%
Kemah (C) 1634 $2,631,702,105.60 126 7.7% $910,699,063 34.6% 555 34.0% $1,617,313,325 61.5%
La Marque (C) 10749 $7,927,292,522.28 6,169 57.4% $4,615,552,789 58.2% 6,505 60.5% $4,747,244,710 59.9%
League City (C) 46742 $31,237,974,594.10 313 0.7% $271,823,631 0.9% 4,450 9.5% $2,733,061,369 8.7%
Santa Fe (C) 7942 $4,831,628,162.13 0 0.0% $0 0.0% 2 0.0% $683,161 0.0%
Tiki Island (V) 868 $365,209,145.44 624 71.9% $242,284,194 66.3% 708 81.6% $305,474,558 83.6%
Galveston County (Total) 209947 $166,321,604,688.46 50,086 23.9% $45,671,691,795 27.5% 98,585 47.0% $87,001,755,597 52.3%
Sources: NOAA 2014; Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Table 4-54. Number of Buildings in the SLOSH Category 3 through 4 Hurricane Inundation Hazard Areas
Jurisdiction
Total Number of
Buildings
Total Replacement Cost
Value (RCV)
Storm Surge Category 3 Storm Surge Category 4
Number of
Buildings
Percent of
Total
Total Replacement
Cost Value
Percent of
Total
Number of
Buildings
Percent of
Total
Total Replacement
Cost Value
Percent
of Total
Bayou Vista (C) 1365 $445,354,087.33 1,323 96.9% $426,025,064 95.7% 1,323 96.9% $426,025,064 95.7%
Clear Lake Shores (C) 1155 $904,562,368.66 1,147 99.3% $899,559,394 99.4% 1,149 99.5% $900,188,943 99.5%
Dickinson (C) 10351 $6,601,710,645.63 9,668 93.4% $6,241,423,825 94.5% 10,324 99.7% $6,594,840,170 99.9%
Friendswood (C) 14891 $10,815,456,384.12 474 3.2% $282,516,903 2.6% 2,492 16.7% $2,379,152,704 22.0%
Hitchcock (C) 5452 $4,592,036,651.86 5,269 96.6% $4,099,893,161 89.3% 5,407 99.2% $4,505,169,550 98.1%
Jamaica Beach (C) 1291 $458,205,838.82 1,218 94.3% $433,511,885 94.6% 1,207 93.5% $430,756,581 94.0%
Kemah (C) 1634 $2,631,702,105.60 1,583 96.9% $2,579,015,109 98.0% 1,601 98.0% $2,590,925,240 98.5%
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-100
2022 Update
Jurisdiction
Total Number of
Buildings
Total Replacement Cost
Value (RCV)
Storm Surge Category 3 Storm Surge Category 4
Number of
Buildings
Percent of
Total
Total Replacement
Cost Value
Percent of
Total
Number of
Buildings
Percent of
Total
Total Replacement
Cost Value
Percent
of Total
La Marque (C) 10749 $7,927,292,522.28 8,883 82.6% $6,511,093,962 82.1% 10,421 96.9% $7,545,708,277 95.2%
League City (C) 46742 $31,237,974,594.10 21,998 47.1% $14,955,152,012 47.9% 35,640 76.2% $24,290,366,490 77.8%
Santa Fe (C) 7942 $4,831,628,162.13 562 7.1% $263,374,449 5.5% 1,850 23.3% $813,519,970 16.8%
Tiki Island (V) 868 $365,209,145.44 708 81.6% $305,322,200 83.6% 708 81.6% $305,875,137 83.8%
Galveston County (Total) 209947 $166,321,604,688.46 144,078 68.6% $119,703,104,280 72.0% 170,325 81.1% $138,655,890,684 83.4%
Sources: NOAA 2014; Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-101
2022 Update
Impact on Critical Facilities
Critical facilities are at risk of being impacted by high winds associated with structural damage, or falling tree
limbs/flying debris, which can result in the loss of power. Power loss can greatly impact households, business
operations, public utilities, and emergency personnel. For example, vulnerable populations in Galveston County
are at risk if power loss results in interruption of heating and cooling services, stagnated hospital operations, and
potable water supplies. Emergency personnel such as police, fire, and EMS will not be able to effectively
respond in a power loss event to maintain the safety of its citizens.
Hazus estimates that critical facilities in Galveston County has a 47.7-percent probability of sustaining minor to
moderate damages from the 100-year MRP hurricane wind event. Hazus also estimates that there are critical
facilities that have a 65.8-percent probability of sustaining severe damage from the 500-year MRP hurricane
wind event. Refer to Section 4.3.13 (Thunderstorm Wind) for details on the imp acts of winds on critical
facilities.
The critical facilities and lifelines located in the Category 1 through 4 inundation zones are summarized in Table
4-55. Over 78-percent of the critical facilities in the County are exposed to the Category 4 SLOSH inundation
area.
Table 4-55. Damage Level to Critical Facilities Exposed to Category 1 through 4 SLOSH Hazard Areas
FEMA Lifeline Category
Number
of
Lifelines
Number of
Lifelines Located
in the Storm
Surge SLOSH
Category 1
Hazard Area
Number of
Lifelines Located
in the Storm
Surge SLOSH
Category 2
Hazard Area
Number of
Lifelines Located
in the Storm
Surge SLOSH
Category 3
Hazard Area
Number of
Lifelines Located
in the Storm
Surge SLOSH
Category 4
Hazard Area
Communications 111 20 35 68 87
Energy 598 219 336 422 491
Food, Water, Shelter 162 66 131 145 150
Hazardous Materials 68 33 62 66 66
Health and Medical 91 15 51 68 81
Safety and Security 405 89 200 321 358
Transportation 882 211 373 511 590
Galveston County (Total) 2,317 653 1,188 1,601 1,823
Source: Hazus v4.2
At this time, Hazus does not estimate losses to transportation lifelines and utilities as part of the hurricane model.
Transportation lifelines are not considered particularly vulnerable to the wind hazard; they are more vulnerable
to cascading effects such as flooding, falling debris etc. Impacts to transportation lifelines affect both short-term
(e.g., evacuation activities) and long-term (e.g., day-to-day commuting) transportation needs. Furthermore,
evacuation routes are vulnerable to coastal storm surge events and hurricane wind events.
Impact on Economy
Damage to structures from flooding and wind can be the most immediate result of coastal storm events; however,
this damage can have long-lasting impacts on the economy. When a business is closed during storm recovery,
there is lost economic activity in the form of day-to-day business and wages to employees. Overall, economic
impacts include the loss of business function (e.g., tourism, recreation), damage to inventory, relocation costs,
wage loss and rental loss due to the repair/replacement of buildings. As evidenced by Hurricane Harvey, the
State of Texas, including Galveston County, lost millions of dollars in wages and economic activity.
Hazus estimates the total economic loss associated with each storm scenario (direct building losses and business
interruption losses). Direct building losses are the estimated costs to repair or replace the damage caused to the
Section 4.3.8 - Hurricane and Tropical Storm
Galveston County, TX | Hazard Mitigation Plan 4-102
2022 Update
building. This is reported in the “Impact on General Building Stock” section discussed earlier. Business
interruption losses are the losses associated with the inability to operate a business because of the wind damage
sustained during the storm or the temporary living expenses for those displaced from their home because of the
event.
Debris management can be costly and may also impact the local economy. Hazus estimates the amount of
building and tree debris that may be produced as result of the 100- and 500-year MRP wind events. Because the
estimated debris production does not include flooding, this is likely a conservative estimate and may be higher
if multiple impacts occur. According to the Hazus Hurricane User Manual, estimates of weight and volume of
eligible tree debris consist of downed trees that would likely be collected and disposed at public expense. Refer
to the User Manual for additional details regarding these estimates.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Any areas of growth could be potentially impacted by the hurricane and tropical storm hazard because the entire
County is exposed and vulnerable; however, due to increased standards and codes, new development can be less
vulnerable to the hazard compared with the aging building stock in the County.
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2015-2019 American Community Survey estimated population of 350,682. The population of the County is
expected to increase over the next few years. The increase in population will expose more people to the hurricane
and tropical storm hazard.
Climate Change
The entire State of Texas is projected to experience an increase in the frequency and severity of extreme storms
and rainfall. Major clusters of summertime thunderstorms in North America will grow larger, more intense, and
more frequent later this century in a changing climate, unleashing far more rain and posing a greater threat of
flooding across wide areas (UCAR 2017). An increase in storms will produce more wind events and may
increase hurricane and tropical storm activity (Climate Central 2016). Overall, Galveston County will continue
to remain vulnerable to the hurricane and tropical storm hazard.
Changes in Vulnerability Since the 2017 HMP
Galveston County continues to be vulnerable to hurricanes and tropical storms. Hurricane models on population
exposed and debris created were not run for the 2017 HMP; therefore, estimated losses were not populated.
Furthermore, the building stock has increased significantly, from $17 billion exposed in 2016 to over $96 billion
in this update. Overall, the vulnerability assessment presented in this update uses Hazus v4.2 and a more accurate
and updated building inventory. This provides more accurate estimated exposure and potential losses for
Galveston County.
Section 4.3.9 - Land Subsidence
Galveston County, TX | Hazard Mitigation Plan 4-103
2022 Update
4.3.9 Land Subsidence
The following section provides the hazard profile and vulnerability assessment for the land subsidence hazard
in Galveston County.
Hazard Profile
Description
Land subsidence is the gradual lowering of land-surface elevation. In the Houston-Galveston region, land
subsidence is caused by compaction of fine-grained aquifer sediments (silts and clays) below the land surface
due to groundwater withdrawals. Removing water from fine-grained aquifer sediments compresses the aquifer
leaving less pore space available to store water resulting in the lowering (sinking or settling) of the land-surface.
Most compaction that occurs as a result of groundwater withdrawals is irreversible; even if groundwater levels
rise, compacted sediments and the associated land-surface lowering would remain (USGS n.d.).
Consequences of land subsidence in the Houston-Galveston Region:
• Reduces the ability to store water in an aquifer.
• Partially or completely submerges land.
• Collapses water well casings.
• Disrupts collector drains and irrigation ditches.
• Alters the flow of creeks and bayous which may increase the frequency and severity of flooding.
• Damages roadways, bridges, building foundations, and other infrastructure.
Location
USGS measures over groundwater levels in over 700 wells in an 11-county area annually in the Houston-
Galveston area in order to develop a regional depiction of groundwater levels. The cumulative compaction in
the Chicot and Evangeline aquifers are measured at 13 extensometer stations in the 11-county area (USGS n.d.).
An extensometer is a device that measures the deformation of the ground in these areas.
Water-level altitude contours, wells, and compaction data have been combined in an interactive map that allows
users to view annual water-level altitudes from 1977 through the present, water-level changes over time, and
historical time series of compaction data (See Figure 4-30). As depicted by the green circles on the map in Figure
4-30, the areas with the greatest rate of land subsidence are near Santa Fe and San Leon.
Section 4.3.9 - Land Subsidence
Galveston County, TX | Hazard Mitigation Plan 4-104
2022 Update
Figure 4-29 The Subsidence Process
Source: (USGS n.d.)
Figure 4-30 Annual Land Subsidence Rates
Source: (USGS 2021)
Section 4.3.9 - Land Subsidence
Galveston County, TX | Hazard Mitigation Plan 4-105
2022 Update
Extent
Land subsidence is measured by rates of elevation loss. Figure 4-30 shows the areas near Santa Fe and San Leon
are shown to experience annual subsidence of 1 to 1.5 cm, while other areas in the County experience subsidence
at a rate of 0.5 cm to 1 cm per year. Figure 4-31 shows the estimated subsidence in total feet in 110 years from
1906 to 2016.
Figure 4-31 Estimated Subsidence Between 1906 and 2016
Source: (Harris-Galveston Subsidence District 2018)
Groundwater levels also decline as aquifer sediments are compacted and groundwater storage capability is
reduced. Figure 4-32 shows the receded water level contours of the Chicot Aquifer between 1977 and 2019.
Figure 4-32 Groundwater Contour Change Between 1977 and 2019
Source: (USGS 2021)
Section 4.3.9 - Land Subsidence
Galveston County, TX | Hazard Mitigation Plan 4-106
2022 Update
Worst-Case Scenario
A worse-case scenario for land subsidence is that it would continue at its current rates of between >-0.5 and -1.5
centimeters per year according to USGS surface GPS monitors and over time, impact the integrity of the built
environment and worsen the effects of coastal flooding. Impacts from land subsidence include road closures,
damage to infrastructure and buildings, and inaccessible areas that can disrupt emergency response.
Previous Occurrences and Losses
Subsidence is a continuous hazard, and its effects are intimately intertwined with those of other natural forces
and episodic hazardous events. Rates of subsidence have decreased across Galveston County, but its effects
continue to compound.
Climate Change Projections
While there is no established connection that climate change increases land subsidence, secondary impacts of
climate change such as drought and flood may have a greater impact on areas experiencing land subsidence. As
drought levels increase, the need to pump water from aquifers also increases which exacerbates subsidence. As
sea levels rise, coastal areas that have lost elevation due to subsidence will experience more frequent coastal
flooding (Shirzaei and Bürgmann 2018).
Probability of Future Events
It is anticipated that land subsidence will continue to occur in Galveston County. As the frequency of drought
conditions continues to increase, the probability for future subsidence events will likely increase as well. Due
to the gradual nature of this hazard and the lack of data on individual land subsidence events, the probability
of future events is based on previous events and input from the Steering Committee. The probability of
occurrence for land subsidence in the planning area is considered rare (between 1 and 10% annual chance of
occurring). Refer to Section 4.4 for additional information on the hazard ranking methodology and probability
criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entire County is vulnerable to land subsidence hazards; however, the eastern portion of the Harris-Galveston
Subsidence District along the Houston Bay Ship Channel is especially vulnerable. This location is near Bayou
Vista, Clear Lake Shores, Hitchcock, Kemah, and unincorporated areas of Galveston County.
Impact on Life, Health and Safety
Land subsidence is not generally considered an imminent threat to public safety then the changes are gradual
over many years. However, land subsidence has many negative secondary consequences. The decrease in land
surface elevation contributes to an increase in the frequency and extent of flooding, damage to infrastructure,
activation of acceleration of the movement of geologic faults resulting in property damage, erosion, and loss of
submerged aquatic vegetation, all of which have negative effects on human life, health, and safety (Galveston
County 2016 HMP). The entire population of the County is vulnerable to this hazard, however, the populations
of Bayou Vista, Clear Lake Shores, Hitchcock, Kemah, are especially vulnerable.
Impact on General Building Stock and Critical Facilities
Estimates of the impact on general building stock and critical facilities are vague. An estimate of the average
annual cost to property owners from 1969 to 1974 for the HGSD was $31,000,000 (measured in 1975 dollars).
Due to the decrease in rates of subsidence, this cost may be much lower today. Costs to relocate or fortify
industrial facilities would likely exceed those estimates (Galveston County 2016 HMP).
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Impact on the Economy
Estimates of the financial impact of subsistence are vague. “Many millions of dollars” are spent reclaiming land
submerged by tidal water, elevating structures such as buildings, wharves, and roadways, constructing levees to
protect against tidal inundation and to repair damage due to fault movement (Galveston County 2016 HMP). For
estimates of the economic impacts on the building stock, see the above section.
Future Changes that May Impact Vulnerability
Understanding future changes that affect vulnerability can assist in planning for future development and ensure
establishment of appropriate mitigation, planning, and preparedness measures. The County considered the
following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change
Projected Development
As discussed, and illustrated in Section 3 (County Profile), areas targeted for future growth and development
have been identified across the County. Any areas of growth could be affected by erosion if the growth areas are
within identified hazard areas. Areas targeted for potential future growth and development could be potentially
impacted by land subsidence if they are located within areas prone to land subsidence
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2019 American Community Survey estimated population of 350,682. Furthermore, the populations of the most
vulnerable jurisdictions have increased. The population of the county is expected to increase over the next few
years. The increase in population will expose more people to the land subsidence hazard.
Climate Change
While there is no established connection that climate change increases land subsidence, secondary impacts of
climate change such as drought and flood may have a greater impact on areas experiencing land subsidence. As
drought levels increase, the need to pump water from aquifers also increases which exacerbates subsidence. As
sea levels rise, coastal areas that have lost elevation due to subsidence will experience more frequent coastal
flooding (Shirzaei and Bürgmann 2018).
Change of Vulnerability
Galveston County’s population increased since the last plan, increasing the number of people at risk to a land
subsidence event. Therefore, the entire County remains vulnerable to land subsidence events.
4.3.10 Lightning
The following section provides the hazard profile and vulnerability assessment for the lightning hazard in
Galveston County.
Profile
Lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground, produced by a
thunderstorm. Energy from lightning channel heats the air to around 18,000°F. This causes the air to rapidly
expand, creating a sound wave known as thunder. Thunder can be heard up to 25 miles away from the lightning
discharge (NOAA n.d.). Figure 4-33 illustrates how lightning develops. Lightning is a major cause of storm-
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related deaths in the United States, with an average of 43 reported fatalities and 243 injuries each year (NWS
n.d.). Between 1990 and 2003, 52 lightning-related deaths was reported in the State of Texas, ranking second
in the United States for deaths associated with lightning strikes (National Lighting Safety Institute 2021).
Figure 4-33. How Lightning Develops
Source: Weather Underground 2021
Location
Lightning occurs with thunderstorms, making all of Galveston County susceptible to the lightning hazard. The
National Lightning Detection Network (NLDN) collects cloud-to-ground lightning data for the continental
United States. Figure 4-34 illustrates the cloud-to-lightning incidence across the United States. The figure
shows that Galveston County experienced 12 to 20 flashes per square mile each year.
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Figure 4-34. Cloud-to-Lightning Incidence, 2008 to 2017
Source: Vaisala 2021
Extent
Lightning is most often associated with moderate to severe thunderstorms. The severity of lightning refers to the
frequency of lightning strikes during a storm. The Lightning Activity Level (LAL) is a scale which describes
lightning activity. The scale is part of the National Fire Danger Rating System. The scale is a range of numbers,
from one to six, which reflects frequency and character of cloud-to-ground lightning (National Wildfire
Coordinating Group n.d.) (NWS n.d.).
Table 4-56. Lightning Activity Level
Lightning Activity Level (LAL) Conditions
1 No thunderstorms
2 Isolated thunderstorms. Light rain will occasionally reach the ground. Lightning is
very infrequent, 1 to 5 cloud to ground strikes in a five-minute period.
3 Widely scattered thunderstorms. Light to moderate rain will reach the ground.
Lightning is infrequent, 6 to 10 cloud to ground strikes in a 5-minute period.
4 Scattered thunderstorms. Moderate rain is commonly produced Lightning is frequent,
11 to 15 cloud to ground strikes in a 5-minute period.
5 Numerous thunderstorms. Rainfall is moderate to heavy. Lightning is frequent and
intense, greater than 15 cloud to ground strikes in a 5-minute period.
6
Dry lightning (same as LAL 3 but without rain). This type of lightning has the
potential for extreme fire activity and is normally highlighted in fire weather forecasts
with a Red Flag Warning.
Sources: National Wildfire Coordinating Group 2021; NWS 2021
Worst-Case Scenario
A worst-case scenario for lightning strikes would be an event with multiple strikes that result in injury and death
like the September 2003 event, or major structural damage like the August 2018 event. This type of event would
be a 4 or 5 on the LAL scale. An event with frequent lightning strikes could lead to power outages, structural
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fires, injuries, and deaths. Countywide power outages would disrupt operations, inundate shelters, increase
emergency response calls, and impact critical services that relies on power to assist the community.
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
lightning strikes in Galveston County. According to the NOAA-NCEI Storm Events Database, Galveston
County has been impacted by 19 lightning events between 1996 and 2020 that resulted in 5 deaths and caused
almost $3.3 million in property damage (refer to Table 4-57).
Table 4-57. Lightning Events 1996-2020
Hazard Type
Number of
Occurrences
Between 1996
and 2020
Total
Fatalities Total Injuries
Total
Property
Damage ($)
Total Crop
Damage ($)
Lightning 19 5 3 $3,259,000 -
Sources: NOAA-NCEI 2021; Galveston County HMP 2017
Note: Due to limitations in data, not all thunderstorm wind events occurring between 1950 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated
As stated earlier, lightning occurs with thunderstorms. Between 1953 and 2021, the State of Texas was included
in five thunderstorm or hail-related FEMA major disaster (DR) or emergency (EM) declarations. Of those
declarations, Galveston County was included in one declaration. Table 4-58 lists FEMA DR and EM declarations
for Galveston County.
Table 4-58. Thunderstorm-Related FEMA Declarations for Galveston County, 1953 to 2021
FEMA Declaration
Number Date(s) of Event Incident Type Incident Title
DR-1041 October 14-November 8, 1994 Flood Severe Thunderstorms and Flooding
Source: FEMA 2021
This HMP update includes known lightning strikes that have impacted Galveston County between 2016 and
2021. These events listed in Table 4-59 represent only those that were reported in the NOAA-NCEI Storm
Events Database, FEMA, and the Galveston County 2017 HMP. However, local knowledge indicates more
instances of lightning strikes occurring in the County. Therefore, Table 4-59 may not represent all lightning
strikes that have occurred prior to or since 2016.
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Table 4-59. Lightning Events in Galveston County, 2016 to 2021
Date of
Event
Event
Type
FEMA
Declaration
Number
(if
applicable)
County
Designated? Deaths Injuries Damages Event Details*
June 28,
2016 Lighting N/A N/A - - $8,000 A lightning strike caused electrical damage to the League City’s City Hall's
parking lot lights.
August
29, 2018 Lighting N/A N/A - - $745,000 Lightning struck a home and caused a fire that destroyed the property.
August
29, 2018 Lighting N/A N/A - - $1,000 Lightning struck and damaged a house.
August
29, 2021 Lightning N/A N/A - - $250,000 Lightning strike initiated a fire which severely damaged a two story home.
Family and pets were able to evacuate in time with no injuries.
Source(s): FEMA 2021; NOAA-NCEI 2021; Galveston County HMP 2017
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact information may vary and has been summarized in the above table
- Not available/not recorded
FEMA Federal Emergency Management Agency
NCEI National Centers for Environmental Information
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Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016).
Climate change may lead to an increase in the number of lightning-producing storms. Major clusters of
summertime thunderstorms in North America will grow larger, more intense, and more frequent later this century
in a changing climate, unleashing far more rain and posing a greater threat of flooding across wide areas (UCAR
2017). At century's end, the number of summertime storms that produce extreme downpours could increase by
more than 400% across parts of the United States, including sections of the Gulf Coast, Atlantic Coast, and the
Southwest. In addition, the intensity of individual extreme rainfall events could increase by a s much as 70% in
some areas (National Science Foundation 2016).
Probability of Future Occurrences
Table 4-60 summarizes data regarding the probability of occurrences of lightning events in Galveston County
based on the historic record. The information used to calculate the probability of occurrences is based on the
2017 Galveston HMP, the NOAA-NCEI Storm Events Database, and FEMA.
Table 4-60. Probability of Future Occurrence of Lightning Events
Hazard Type
Number of Occurrences Between 1954
and 2021
% chance of occurrence in any
given year
Lightning 20 29.4%
Source: NOAA-NCEI 2021; FEMA 2021; Galveston County HMP 2017
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected lightning events
since 1968. Due to limitations in data, not all lightning events occurring between 1954 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated
Galveston County will continue experiencing the direct and indirect impacts of lightning events each year. Based
on information from the 2017 Galveston County HMP, FEMA and the NOAA-NCEI Storm Events Database,
there have been fifteen reported lightning strikes in the County in 20 years. However, as stated earlier, local
knowledge indicates many more instances of lightning strikes occurring in the County. Therefore, the calculated
probability based on recorded incidents might not represent the actual probability of occurrence. Based on
historical records and input from the Steering Committee, the probability of occurrence for thunderstorm events
in Galveston County is considered occasional (between 10 and 100% annual chance of occurring). Refer to
Section 4.4 for additional information on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the lightning hazard; therefore, all assets within the
County (population, structures, critical facilities, and lifelines), as described in Section 3 (County Profile), are
potentially vulnerable to a thunderstorm event. The following text evaluates and estimates the potential impact
of the lightning hazard in the County.
Impact on Life, Health and Safety
Across the United States, the 10-year average (2009 to 2018) for lightning-caused fatalities is 27, while the 30-
year average (1989 to 2018) is 43 (NWS 2020). Refer to Figure 4-35 for an illustration of these statistics.
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According to the NOAA-NCEI Storm Events Database, there has been five fatalities and three injuries as a result
of lightning events from 1996 to 2021.
Figure 4-35. Weather Fatalities in the United States, 2018
Source: NOAA 2020
The impact of a lightning on life, health, and safety is dependent upon several factors including the severity of the
event and whether adequate warning time was provided to residents. The entire population of Galveston County
is assumed to be exposed to this hazard.
Lightning can be responsible for deaths, injuries, and property damage. Lightning-based deaths and injuries
typically involve heart damage, inflated lungs, or brain damage, as well as loss of consciousness, amnesia,
paralysis, and burns, depending on the severity of the strike. Additionally, most people struck by lightning
survive, although they may have severe burns and internal damage. People located outdoors (i.e., recreational
activities and farming) are considered most vulnerable to lightning strikes because there is little to no warning,
and shelter might not be available. Moving to a lower risk location will decrease a person’s vulnerability.
Impact on General Building Stock
For the purpose of this plan update, the entire general building stock and all infrastructure in Galveston County
are considered exposed to the lightning hazard. Lightning can spark wildfires or building fires, especially if
structures are not protected by surge protectors on critical electronic, lighting, or information technology
systems. While damage to the building stock is possible as a result of lightning, it is difficult to estimate and
would not have as wide of an impact as a high wind or tornado event.
Impact on Critical Facilities
For the purpose of this plan update, all critical facilities in Galveston County are considered exposed to the
lightning hazard.
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Impact on Economy
According to NOAA’s Technical Paper on Lightning Fatalities, Injuries, and Damage Reports in the United
States from 1959 - 1994, monetary losses for lightning events range from less than $50 to greater than $5 million
(larger losses associated with forest fires with homes destroyed and crop loss) (NOAA 1997).
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. Areas
targeted for potential future growth and development could be potentially impacted by thunderstorms since the
entire County is exposed to the lightning hazard. However, due to increased standards and codes, new
development can be less vulnerable to the lightning hazard compared with the aging building stock in the County.
Projected Changes in Population
The County experienced an increase in population between the 2010 Census (291,309) and the estimated 2015-
2019 American Community Survey estimated population of 350,682. The population of the County is expected
to increase over the next few years. The increase in population will expose more people to the lightning hazard.
Climate Change
Climate change may lead to an increase in the number of lightning strikes and lightning-producing storms. Major
clusters of summertime thunderstorms in North America will grow larger, more intense, and more frequent later
this century in a changing climate, leading to increased rainfall and posing a greater threat of flooding across
wide areas (University Corporation for Atmospheric Research [UCAR] 2017). The changing climate may also
increase the frequency of lightning flashes could rise by an estimated 50-percent across the continental United
States over the next century. A warmer atmosphere can hold more moisture and moisture is one of the key
ingredients for triggering a lightning strike (Lee 2014).
Changes in Vulnerability Since the 2017 HMP
Galveston County’s population increased since the last plan; increasing the number of people impacted during a
lightning. Therefore, the entire County remains vulnerable to lightning.
4.3.11 Pandemic
This section provides the hazard profile and vulnerability assessment for the pandemic hazard for Galveston
County.
Profile
Hazard Description
An outbreak or an epidemic occurs when new cases of a certain disease, in a given population, substantially
exceed what is expected. An epidemic may be restricted to one locale, or it may be global, at which point it is
called a pandemic. Pandemic is defined as a disease occurring over a wide geographic area and affecting a high
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proportion of the population. A disease outbreak can cause sudden, pervasive illness in all age groups on a local
or global scale. A pandemic is a novel virus to which humans have no natural immunity that spreads from person-
to-person. A pandemic will cause both widespread and sustained effects and is likely to stress the resources of
both the State and federal government (Madhav, et al. 2017). In addition to health impacts, disease outbreaks
reaching pandemic proportions can cause social and economic impacts on a global scale (Shang, Li and Zhang
2021).
Coronavirus
Coronavirus disease (COVID-19) is an infectious disease first identified in 2019. The virus rapidly spread into
a global pandemic by spring of 2020. Older people, and those with underlying medical problems like
cardiovascular disease, diabetes, chronic respiratory disease, and cancer are more likely to develop serious illness
(World Health Organization n.d.). With the virus being relatively new, information regarding transmission and
symptoms of the virus is still new. The COVID-19 virus spreads primarily through droplets of saliva or discharge
from the nose when an infected person coughs or sneezes. Reported illnesses have ranged from mild symptoms
to severe illness. Reported symptoms include fever or chills, cough, shortness of breath or difficulty breathing
and fatigue. Symptoms may appear 2-14 days after exposure to the virus (CDC 2021).
In an effort to slow the spread of the virus, the federal government and states have urged the public to avoid
touching of the face, properly wash hands often, and use various social distancing measures. At the time of this
plan update, there are three approved and authorized vaccines available in the United States to reduce risk of
severe illness (CDC 2021).
Influenza
The risk of a global influenza pandemic has increased over the last several years. This disease is capable of
claiming thousands of lives and adversely affecting critical infrastructure and key resources. An influenza
pandemic has the ability to reduce the health, safety, and welfare of the essential services workforce; immobilize
core infrastructure; and induce fiscal instability.
Pandemic influenza is different from seasonal influenza (or "the flu") because outbreaks of seasonal flu are
caused by viruses that are already among people. An influenza pandemic is a global outbreak of a new influenza
A virus. Pandemics happen when new (novel) influenza A viruses emerge which are able to infect people easily
and spread from person to person in an efficient and sustained way (CDC n.d.).
At the national level, the CDC’s Influenza Division has a long history of supporting the World Health
Organization (WHO) and its global network of National Influenza Centers (NIC). With limited resources, most
international assistance provided in the early years was through hands-on laboratory training of in-country staff,
the annual provision of WHO reagent kits (produced and distributed by CDC), and technical consultations for
vaccine strain selections. The Influenza Division also conducts epidemiologic research including vaccine studies
and serologic assays and provided international outbreak investigation assistance (CDC n.d.).
West Nile Virus
West Nile Virus (WNV) encephalitis is a mosquito-borne viral disease, which can cause an inflammation of the
brain. WNV is commonly found in Africa, West Asia, the Middle East, and Europe. West Nile Virus was first
reported in Texas in 2002. In a small number of cases, WNV has been spread by blood transfusion, which has
resulted in the screening of blood donations for the virus in the US, or by organ transplantation. WNV can also
be spread from mother to baby during pregnancy, delivery, or breast-feeding in a small number of cases. The
symptoms of severe infection (West Nile encephalitis or meningitis) can include headache, high fever, neck
stiffness, muscle weakness, stupor, disorientation, tremors, seizures, paralysis, and coma. WNV can cause
serious illness, and in some cases, death. Usually, symptoms occur from two to 14 days after being bitten by an
infected mosquito (Texas Department of State Health Services n.d.).
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Location
Disease outbreaks can occur without regard for location. However, factors such as density, visitation, and the
length of time in which the public spends in a location all contribute to the spread of infectious diseases. For
example, COVID-19 is more likely spread by persons in close contact. Indoor areas in which people are in close
contact with each other appear to be significant vectors for the disease, which is spread through respiratory
droplets. Infectious diseases spread by insects may be subject to other types of location hazards. For example,
the prevalence of standing water can provide breeding grounds for diseases such as West Nile Virus. Diseases
that can infect humans are variable in nature and methods of transmission. Ultimately, residents need to be
vigilant about diseases altogether in order to better understand and respond to disease outbreak hazards.
Extent
The exact size and extent of an infected population depends on how easily the illness is spread, the mode of
transmission, and the amount of contact between infected and uninfected individuals. The transmission rates
of pandemic illnesses are often higher in more densely populated areas. The transmission rate of infectious
diseases will depend on the mode of transmission of a given illness.
Coronavirus
The most recent large-scale disease outbreak is COVID-19, which is ongoing at the time of this report’s
publication.
Texas’s first COVID-19 cases were reported on March 6th, 2020. By mid-April, hundreds of new cases were
being confirmed each day. Beginning in May, daily new cases in excess of 1,000 were reported, with the number
of daily new cases growing near-exponentially beginning in mid-June. On a county-wide basis, there have been
55,166 confirmed cases as of December 2, 2021 (Galveston County Health District 2021), The graph in Figure
4-36 shows the rate of confirmed cases in Galveston County through December 3, 2021 (Texas Department of
State Health Services 2021).
Figure 4-36. COVID-19 Confirmed Case Rate in Galveston County, Texas
Source: Texas Department of State Health Services, 2021
A significant metric of COVID-19 has been hospital bed utilization. Efforts to “flatten the curve” of new reported
cases are meant to avoid overwhelming medical systems by heading off hospital over-capacity issues. Figure
4-37 shows that as of December 3, 2021, COVID-19 cases account for 3.4 percent of general beds in use and
hospital bed use is below capacity in Galveston County.
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Figure 4-37. Hospital Census Data, Galveston County, Texas
Source: SETRAC
Previous Occurrences and Losses
Between 1953 and 2021, FEMA issued a disaster (DR) or emergency (EM) declaration for the State of Texas
for one pandemic-related event. Galveston County was included in this declaration for COVID-19. For the 2022
HMP update, known disease outbreaks that have impacted Galveston County between 2003 and 2021 are
identified in Table 4-61 below.
Table 4-61. Public Health Events in Galveston County, 2014 to December 3, 2021
Date(s) of Event Event Type
FEMA
Declaration
Number
(if applicable)
Galveston
County
Designated? Description
2003-Present West Nile
Virus None N/A Between 2003 and 2021, 22 human cases of West
Nile Virus were reported in Galveston County.
2015-Present Zika Virus None N/A
Nine Galveston County residents were reported to
contract Zika in 2016, a mosquito-borne illness.
All cases were associated with travel, and none
were reported to have been contracted locally. The
vast majority of cases in Texas were determined to
have not been contracted locally.
March 2020-
Present
Novel
Coronavirus
DR-4485
EM-3458 Yes As of December 3, 2021, there were 55,166
confirmed COVID-19 cases in Galveston County.
Sources: FEMA 2021; Galveston County Health District 2021; CDC 2021
Climate Change Projections
Climate change will likely have significant indirect impacts on disease outbreaks. In Texas, higher temperatures,
decreased water availability, and more severe storm events are anticipated due to climate change. According to
the World Health Organization, changing climatic conditions are being studied for impacts upon disease
transmission. Seasonal infectious diseases that are influenced by meteorological conditions may see significant
variability in recurrence and duration. The World Health Organization concludes that variations in infectious
disease transmission patterns are likely major consequences of climate change.
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Probability of Future Occurrences
Though occurrences of disease outbreaks overall are often difficult to p redict at the local level, it is anticipated
that Galveston County will continue to be impacted by disease outbreaks for the foreseeable future. Seasonality
for cold and flu is well established and anticipated in Texas on an annual basis.
Based on the recent disease outbreak cases shown in Table 4-62, the future occurrence of disease outbreak cases
in the planning area can be considered frequent (100% chance of occurring; occurs multiple times a year). Refer
to Section 4.4 for additional information on the hazard ranking methodology and probability criteria.
Table 4-62 Probability of Pandemic Cases
Hazard Type Number of Occurrences Between 2014 and
December 3, 2021
% chance of occurrence in any
given year
Pandemic Cases 55,197 100%
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected events since 1968.
Due to limitations in data, not all pandemic events occurring between 1954 and 1996 are accounted for in the tally of occurrences. As
a result, the number of hazard occurrences is underestimated.
Vulnerability Assessment
To understand risk, a community must evaluate what assets are exposed or vulnerable to the identified hazard.
The following discusses Galveston’s vulnerability, in a qualitative nature, to the disease outbreak hazard.
Impact on Life, Health and Safety
The entire population of Galveston County is vulnerable to the disease outbreak hazard. Due to a lack of
quantifiable loss information, a qualitative assessment was conducted to evaluate the assets exposed to this
hazard and the potential impacts associated with this hazard. Healthcare providers and first responders have an
increased risk of exposure due to their frequent contact with infected populations. Areas with a higher population
density also have an increased risk of exposure or transmission of disease to do the closer proximity of population
to potentially infected people.
Most recently with COVID-19, the Centers for Disease Control and Prevention have indicated that persons over
65 years and older, persons living in a nursing home or long-term care facility, and persons with underlying
medical conditions such as diabetes, severe obesity, serious heart conditions, etc. are at a higher risk of getting
severely ill (CDC 2020). According to the 2019 American Community Survey, 13.1% of Galveston County
residents (or approximately 46,103 people) are over the age of 65. As of January 13, 2022, there have been
68,933 positive COVID-19 cases in Galveston County (GCHD 2022).
Impact on General Building Stock
No structures are anticipated to be directly affected by pandemic events.
Impact on Critical Facilities
No critical facilities are anticipated to be affected by disease outbreaks. Hospitals and medical facilities will
likely see an increase in patients, but it is unlikely that there will be damages or interruption of services. However,
large rates of infection may result in an increase in the rate of hospitalization which may overwhelm hospitals
and medical facilities and lead to decreased services for those seeking medical attention. The 2020 coronavirus
pandemic has led to overwhelmed hospitals in numerous hotspots.
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Impact on Economy
Disease outbreaks impacts on the economy and estimated dollar losses are difficult to measure and quantify.
Costs associated with the activities and programs implemented to conduct surveillance and address disease
outbreaks have not been quantified in available documentation. As evidenced in the COVID-19 outbreak,
quarantines, shutdowns, and social distancing measures can have outsized economic impacts, particularly on the
leisure, tourism, and food/accommodations sectors.
Future Changes that May Impact Vulnerability
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Any areas of growth could be potentially impacted by the disease outbreak hazard because the entire planning
area is exposed and vulnerable. Additional development of structures in close proximity to waterbodies or areas
with high population density are at an increased risk.
Projected Changes in Population
The County experienced an increase in population between the 2010 Census (291,309) and the estimated 2015-
2019 American Community Survey estimated population of 350,682. The population of the County is expected
to increase in the near future. The increase in population will expose more people to the pandemic hazard as
residents move into area and the population exposed increases. Population density changes when househ olds
move throughout the County could influence the number of persons exposed to disease outbreaks. Higher
density jurisdictions are not only at risk of greater exposure to disease outbreak, density may also reduce
available basic services provided by critical facilities such as hospitals and emergency facilities for persons that
are not affected by a disease.
Climate Change
The relationship between infectious diseases occurrence and climate change is difficult to predict with certainty.
However, there may be linkages between the two. Changes in the environment may create a more livable habitat
for vectors carrying disease as suggested by the Centers for Disease Control and Prevention (CDC n.d.).
Localized changes in climate and human interaction may also be a factor in the spread of disease. For example,
in the wake of Hurricane Harvey prolonged and intense precipitation provided breeding grounds for mosquitos
that necessitated mosquito control measures.
The relationship between climate change and infectious diseases is not universally agreed upon. Climate change
may affect the spread of disease, while others are not convinced. However, research indicates that the only
force at work in increasing the spread of infectious diseases into the future. Other factors, such as expanded rapid
travel and evolution of resistance to medical treatments, are already changing the ways pathogens infect people,
plants, and animals. As climate change accelerates it is likely to work synergistically with many of these factors,
especially in populations increasingly subject to massive migration and malnutrition (Harmon 2010).
Section 4.3.11 - Pandemic
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Changes in Vulnerability Since the 2017 HMP
Pandemic is a new hazard profile for the 2022 HMP update. The occurrence and prevalence of COVID-19 in the
County underscores the need to address disease outbreak as part of the hazard mitigation planning process. The
County will continue to be exposed and vulnerable to pandemic events.
Section 4.3.12 - Severe Winter Storm
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2022 Update
4.3.12 Severe Winter Storm
The following section provides the hazard profile and vulnerability assessment for the severe winter storm hazard
in Galveston County.
Profile
Hazard Description
Severe winter storms bring the threat of snow, freezing rain, and ice storms to Galveston County. A winter storm
is a weather event in which the main types of precipitation are snow, sleet, or freezing rain. They can be a
combination of heavy snow, blowing snow, and dangerous wind chills. According to the National Severe Storms
Laboratory, the three basic components needed to make a winter storm include the following:
• Below freezing temperatures (cold air) in the clouds and near the ground to make snow and ice.
• Lift, something to raise the moist air to form clouds and cause precipitation, such as warm air colliding
with cold air and being forced to rise over the cold dome or air flowing up a mountainside (oliographic
lifting).
• Moisture to form clouds and precipitation, such as air blowing across a large lake or the ocean.
Some winter storms are large enough to immobilize an entire region while others might only affect a single
community. Winter storms typically are accompanied by low temperatures, high winds, freezing rain or sleet,
and heavy snowfall. The aftermath of a winter storm can have an impact on a community or region for days,
weeks, or even months; potentially causing cold temperatures, flooding, storm surge, closed and blocked
roadways, downed utility lines, and power outages. In Galveston County, winter storms include snowstorms,
blizzards, and ice storms. Extreme cold temperatures and wind chills are associated with winter storms; however,
they are discussed in Section 4.3.6 (Extreme Temperature).
Heavy Snow
According to the National Snow and Ice Data Center (NSIDC), snow is precipitation in the form of ice crystals.
It originates in clouds when temperatures are below the freezing point (32 °F) and water vapor in the atmosphere
condenses directly into ice without going through the liquid stage. Once an ice crystal has formed, it absorbs and
freezes additional water vapor from the surrounding air, growing into snow crystals or a snow pellet, which then
falls to the earth. Snow falls in different forms: snowflakes, snow pellets, or sleet. Snowflakes are clusters of ice
crystals that form from a cloud. Figure 4-38 depicts snow creation.
Figure 4-38. Snow Creation
Source: (NOAA NSSL n.d.)
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Snow pellets are opaque ice particles in the atmosphere. They form as ice crystals fall through super-cooled
cloud droplets, which are below freezing but remain a liquid. The cloud droplets then freeze to the crystals. Sleet
is made up of drops of rain that freeze into ice as they fall through colder air layers. They are usually smaller
than 0.30 inches in diameter (NSIDC 2020).
Figure 4-39. Sleet Creation
Source: (NOAA NSSL n.d.)
Blizzards
A blizzard is a winter snowstorm with sustained or frequent wind gusts of 35 miles per hour (mph) or more,
accompanied by falling or blowing snow reducing visibility to or below 0.25 mile, as the predominant conditions
over a 3-hour period. Extremely cold temperatures often are associated with blizzard conditions but are not a
formal part of the definition. The hazard, created by the combination of snow, wind, and low visibility,
significantly increases when temperatures are below 20 °F. A severe blizzard is categorized as having
temperatures near or below 10 °F, winds exceeding 45 mph, and visibility reduced by snow to near zero. Storm
systems powerful enough to cause blizzards usually form when the jet stream dips far to the south, allowing cold
air from the north to clash with warm, moister air from the south. Blizzard conditions often develop on the
northwest side of an intense storm system. The difference between the lower pressure in the storm and the higher
pressure to the west creates a tight pressure gradient, resulting in strong winds and extreme conditions caused
by the blowing snow (NWS n.d.).
Ice Storms
An ice storm describes those events when damaging accumulations of ice are expected during freezing rain
situations. Significant ice accumulations typically are accumulations of 0.25-inches or greater. Heavy
accumulations of ice can bring down trees, power lines, utility poles, and communication towers. Ice can disrupt
communications and power for days. Even small accumulations of ice can be extremely dangerous to motorists
and pedestrians (NWS 2018).
Section 4.3.12 - Severe Winter Storm
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2022 Update
Figure 4-40. Freezing Rain Creation
Source: (NOAA NSSL n.d.)
Location
Winter storms occur on a regional scale and can happen anywhere in the State of Texas; therefore, all of
Galveston County can experience winter storm events.
Extent
The magnitude or severity of a severe winter storm depends on several factors, including a region’s
climatological susceptibility to snowstorms, snowfall amounts, snowfall rates, wind speeds, temperatures,
visibility, storm duration, topography, time of occurrence during the day and week (e.g., weekday versus
weekend), and time of season.
The extent of a severe winter storm can be classified by meteorological measurements and by evaluating its
societal impacts. The National Oceanic and Atmospheric Administration’s (NOAA’s) National Climatic Data
Center (NCDC) is currently producing the Regional Snowfall Index (RSI) for significant snowstorms that impact
the eastern two-thirds of the United States. The RSI ranks snowstorm impacts on a scale from 1 to 5 and is based
on the spatial extent of the storm, the amount of snowfall, and the interaction of the extent and snowfall totals
with population (based on the 2000 Census). The NCDC has analyzed and assigned RSI values to over 500
storms since 1900 (NOAA NCEI n.d.). Table 4-63 presents the five RSI ranking categories.
Table 4-63. RSI Ranking Categories for the South Climate Region
Category Description RSI Value Snowfall Thresholds
1 Notable 1–3 <2
2 Significant 3–6 >2
3 Major 6–10 >5
4 Crippling 10–18 >10
5 Extreme 18.0+ >15
Source: (NOAA NCEI n.d.)
Note: RSI = Regional Snowfall Index
The NWS operates a widespread network of observing systems, such as geostationary satellites, Doppler radars,
and automated surface observing systems that feed into the current state-of-the-art numerical computer models
Section 4.3.12 - Severe Winter Storm
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to provide a look into what will happen next, ranging from hours to days. The models are then analyzed by NWS
meteorologists who then write and disseminate forecasts (NOAA 2017).
According to the National Weather Service (part of NOAA), the magnitude of a severe winter storm can be
qualified into five main categories by event type:
• Heavy Snowstorm – snowfall accumulating to 4 inches or more in 12 hours or less or snowfall
accumulating to six inches or more in 24 hours or less.
• Sleet Storm – Significant accumulations of solid pellets that form from the freezing of raindrops or
partially melted snowflakes causing slippery surfaces, posing a hazard to pedestrians and motorists.
• Ice Storm – Significant accumulation of rain or drizzle freezing on objects (trees, power lines, roadways)
as it strikes them, causing slippery surfaces and damage from sheer weight of ice accumulations;
significant ice accumulations are usually ¼” or greater.
• Blizzard – sustained winds or frequent gusts of 35 mph or more; considerable blowing snow with
visibility frequently below one-quarter mile prevailing over an extended period.
• Severe Blizzard – Wind velocity of 45 mph, temperatures of 10°F or lower, a high density of blowing
snow with visibility frequently measured in feet prevailing over an extended period.
The NWS uses winter weather watches, warnings, and advisories to ensure that people know what to expect in
the coming hours and days.
• Watches
o Blizzard – Conditions are favorable for blizzard conditions to be met in the next 12 to 48 hours.
o Winter Storm - Issued when sinter storm conditions, defined above, are possible within 24 to
48 hours.
• Warnings
o Blizzard – Issued when sustained winds or frequent gusts ≥ 35 mph combined with blowing
and or falling snow, reducing visibility below 1/4 mile for 3 hours or more, when imminent or
expected within the next 36 hours. Temperatures are assumed below 32°F, and snow should
accumulate at least one inch in 12 hours.
o Winter Storm - Issued when the following conditions, capable of producing high impact and
potentially life threatening conditions, are occurring or expected to occur within the 36 hours:
snow - ≥1 inch in 12 hours; sleet - ≥1/2 inch in 12 hours; and or a combination of snow, sleet,
ice with snow or sleet meeting warning criteria
o Ice Storm - Issued when ≥1/8 inch of Ice is expected to accrete on trees, power lines, and
bridges/overpasses for the entirety of the event. These conditions are capable of producing high
impact and potentially life threatening conditions and are either occurring or expected to occur
within the next 36 hours.
• Advisories
o Winter Weather - Issued when the following conditions, capable of producing significant, but
not necessarily life threatening, inconveniences, are occurring or expected to occur within the
next 36 hours:
▪ Snow: 1/2 to 1 inch in 12 hours
▪ Sleet: < 1/2 inch in 12 hours
▪ Ice: < 1/8 inch in 12 hours
▪ Combination: Snow, sleet, and ice with snow or sleet meeting advisory criteria.
Section 4.3.12 - Severe Winter Storm
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Worst-Case Scenario
Overall, the maximum winter weather extent that can be expected in Galveston County is an RSI Category 3
snowfall event. Because the County is located in the National Centers for Environmental Information’s south
climate region, the amount of snow that can fall for this category event is up to 10 inches; however, the area will
most likely see lower amounts of snow based on history of occurrence. A winter storm of that magnitude has the
potential to cause between $16-166 billion in property damage countywide.
A worst-case severe winter storm scenario would be a storm similar to that of the February 2021 ice storm that
brought extreme temperature lows, deaths and injuries, significant buildup of ice on structures and infrastructure
including highway overpasses. A storm like this could lead to downed trees and power lines, power outages,
closed roadways, and overall impact to the planning area. This would lead to disruption in emergency services
and limited access to essentials (e.g. water, heat).
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
severe winter storm events in Galveston County. According to the NOAA-NCEI storm events database,
Galveston County has been impacted by four winter weather events between 1950 and 2021. Table 4-64 and
Table 4-65 summarize these statistics (NOAA-NCEI 2020).
Table 4-64. Severe Winter Events 1950-2021
Hazard Type
Number of
Occurrences
Between 1950
and 2021 Total Fatalities Total Injuries
Total
Property
Damage ($)
Total Crop
Damage ($)
Blizzard 0 0 0 $0 $0
Heavy Snow 1 0 0 $0 $0
Ice Storm 3 9 0 $12 million $0
Sleet 0 0 0 $0 $0
Winter Storm 0 0 0 0 0
Winter Weather 0 0 0 $0 $0
Total 4 9 0 $12 million $0
Source: NOAA-NCEI 2021
Note: NOAA-NCEI database includes winter-related events starting in 1996. Events that occurred prior to 1996 are not included in the table.
Between 1953 and 2021, FEMA included the State of Texas in one winter storm-related major disaster (DR)
declaration classified as a severe ice storm. Generally, these disasters cover a wide region of the state; therefore,
they may have impacted many counties. Galveston County was included that winter storm-related declaration
(FEMA 2021). For the 2022 update, severe winter weather events were summarized from 2016 to 2021 (see
Table 4-65). For events prior to 2016, refer to the 2016 Galveston County HMP.
Table 4-65. Severe Winter Weather Events in Galveston County, 2016 to 2021
Dates of
Event Event Type
FEMA
Declaration
Number
County
Designated? Event Details*
February
11-21, 2021 Ice Storm DR-4586 Yes
Very cold air and gusty winds overspread SE Texas behind an Arctic
front with wind chill indices from near zero to single digits for much
the period from Sunday night to Tuesday morning. Increased power
demand, wind and ice led to widespread power outages. Bursting
pipes caused many to be without water as well. Numerous fatalities
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Table 4-65. Severe Winter Weather Events in Galveston County, 2016 to 2021
Dates of
Event Event Type
FEMA
Declaration
Number
County
Designated? Event Details*
resulted both from hypothermia, carbon monoxide poisoning and
other effects.
Sources: FEMA 2021; NOAA-NCEI 2021
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact information
may vary and has been summarized in the above table
FEMA Federal Emergency Management Agency
NCEI National Centers for Environmental Information
Climate Change Projections
Changes in climate can affect how much snow falls and influence the timing of the winter snow season. Changes
in the amount of snow covering the ground, and changes in how the snow melts in the spring, will affect the
water supplies that people use for things like farming and making electricity (NSIDC 2010). With these
projections, the County might not experience an increase in winter weather events, but the lack of snow could
impact the water supply.
According to the National Climate Assessment, rising air and water temperatures and changes in precipitation
are intensifying droughts, increasing heavy downpours, reducing snowpack, and causing declines in surface
water quality, with varying impacts across regions. Future warming will add to the stress on water supplies and
adversely impact the availability of water in parts of the United States (USGCRP 2018).
Probability of Future Occurrences
For the 2022 HMP update, the most up-to-date data was collected to calculate the probability of future occurrence
of winter storm events, of all types, for Galveston County. Table 4-66 summarizes data regarding the probability
of occurrences of severe winter storm events in the County based on the historic record. The information used
to calculate the probability of occurrences is based on NOAA-NCEI storm events and FEMA database results.
Table 4-66. Probability of Future Occurrence of Severe Winter Weather Events in Galveston County
Hazard Type
Number of Occurrences Between 1950
and 2021
% chance of occurrence in any given
year
Blizzard 0 0%
Heavy Snow 1 1.39%
Ice Storm 3 4.17%
Sleet 0 0%
Winter Storm 0 0%
Winter Weather 0 0%
Total 4 5.56%
Source: NOAA-NCEI 2021, FEMA 2021
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act and selected severe winter
weather events since 1968. Due to limitations in data, not all severe winter weather events occurring between 1954 and 1996 are
accounted for in the tally of occurrences. As a result, the number of hazard occurrences is underestimated.
Based on the number of winter weather events, the County averages less than one winter weather event each
year. A winter weather event has a 5.56% chance of occurring in any given year. Based on the history of events
and input from the Steering Committee, the probability for severe winter storm events occurring in Galveston
Section 4.3.12 - Severe Winter Storm
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County is considered rare (between 1 and 10% annual chance of occurring). Refer to Section 4.4 for additional
information on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the severe winter storm hazard; therefore, all assets
within the County (population, structures, critical facilities, and lifelines), as described in Section 3 (County
Profile), are potentially vulnerable to a winter weather event. The following text evaluates and estimates the
potential impact of the severe winter storm hazard in the County.
Impact on Life, Health and Safety
For the purposes of this HMP, the entire population of the County (350,682) is exposed to winter storm events
(U.S. Census 2015-2019 ACS 5-Year Population Estimate). The homeless and elderly are considered most
susceptible to this hazard; the homeless due to their lack of shelter and the elderly due to their increased risk of
injuries and death from falls and overexertion or hypothermia from attempts to clear snow and ice.
According to the 2019 ACS 5-Year Population Estimate, 13.1 percent of the population in Galveston County is
65 and over. Winter storm events can reduce the ability of these populations to access emergency services.
Winter weather can immobilize a region and paralyze a city. Additional impacts include stranding commuters,
stopping the flow of supplies, and disrupting emergency and medical services. Accumulations of snow can
collapse buildings and knock down trees and power lines. The cost of snow removal, repairing damages, and
loss of business can have large economic impacts on cities and towns (NSSL 2006)
Impact on General Building Stock
The entire general building stock inventory in Galveston County is exposed and potentially vulnerable to the
severe winter storm hazard; however, properties in poor condition or in particularly vulnerable locations may be
at risk to the most damage. In general, structural impacts include damage to roofs and building frames rather
than building content. Current modeling tools are not available to estimate specific losses for this hazard. As an
alternate approach, the percent damage to structures that could result from severe winter storm conditions is
considered. This allows planners and emergency managers to select a range of potential economic impact based
on an estimate of the percent of damage to the general building stock. Table 4-67 summarizes the estimated loss
to structures. Given professional knowledge and the currently available information, the potential loss for this
hazard is considered to be overestimated because of varying factors (building structure type, age, load
distribution, building codes in place). Therefore, the table’s data should be used as estimates only for planning
purposes with the knowledge that the associated losses for severe winter storm events vary greatly.
Table 4-67. General Building Stock Exposure and Estimated Losses from Severe Winter Storm Events
Jurisdiction
Total Replacement
Cost Value (RCV)
1-Percent
Exposure/Loss
5-Percent
Exposure/Loss
10-Percent
Exposure/Loss
Bayou Vista (C) $445,354,087.33 $4,453,541 $22,267,704 $44,535,409
Clear Lake Shores (C) $904,562,368.66 $9,045,624 $45,228,118 $90,456,237
Dickinson (C) $6,601,710,645.63 $66,017,106 $330,085,532 $660,171,065
Friendswood (C) $10,815,456,384.12 $108,154,564 $540,772,819 $1,081,545,638
Hitchcock (C) $4,592,036,651.86 $45,920,367 $229,601,833 $459,203,665
Jamaica Beach (C) $458,205,838.82 $4,582,058 $22,910,292 $45,820,584
Section 4.3.12 - Severe Winter Storm
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Jurisdiction
Total Replacement
Cost Value (RCV)
1-Percent
Exposure/Loss
5-Percent
Exposure/Loss
10-Percent
Exposure/Loss
Kemah (C) $2,631,702,105.60 $26,317,021 $131,585,105 $263,170,211
La Marque (C) $7,927,292,522.28 $79,272,925 $396,364,626 $792,729,252
League City (C) $31,237,974,594.10 $312,379,746 $1,561,898,730 $3,123,797,459
Santa Fe (C) $4,831,628,162.13 $48,316,282 $241,581,408 $483,162,816
Tiki Island (V) $365,209,145.44 $3,652,091 $18,260,457 $36,520,915
Galveston County
(Total) $166,321,604,688.46 $1,663,216,047 $8,316,080,234 $16,632,160,469
Source: Hazus 4.2, Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on Critical Facilities
Full functionality of critical facilities, such as police, fire, and medical facilities is essential for response during
and after a severe winter storm event. These critical facility structures are largely constructed of concrete and
masonry; therefore, they should only suffer minimal structural damage from severe winter storm events. Heavy
accumulations of ice can bring down trees, electrical wires, telephone poles, utility lines, and communication
towers. Communications and power can be disrupted for days while utility companies work to repair the
extensive damage. Even small accumulations of ice can cause extreme hazards to motorists and pedestrians.
Bridges and overpasses are particularly dangerous because they freeze before other surfaces (NSSL 2006).
Winter weather events, such as ice storms, can lead to power outages. Therefore, it is recommended that critical
facilities install backup power sources.
Infrastructure at risk for this hazard includes roadways that could be damaged due to salt application and
intermittent freezing and warming conditions that can damage roads over time. Severe snowfall requires the
clearing roadways and alerting citizens to dangerous conditions; following the winter season, resources for road
maintenance and repair might be required.
Impact on Economy
The cost of snow and ice removal and repair of roads from the freeze/thaw process can drain local financial
resources. Impacts on the economy also include commuter difficulties into or out of the area for work or school.
The loss of power and closure of roads prevent commuters within the county.
Future Changes that May Impact Vulnerability
Understanding future changes that impact vulnerability in the county can assist in planning for future
development and ensure that appropriate mitigation, planning, and preparedness measures are in place. The
county considered the following factors to examine potential conditions that can affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Any areas of growth could be potentially impacted by the severe winter storm hazard because the entire County
is exposed and vulnerable. The ability of new development to withstand severe winter storm impacts lies in
sound land use practices and consistent enforcement of codes and regulations for new construction.
Section 4.3.13 - Thunderstorm Wind
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Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2015-2019 American Community Survey estimated population of 350,682. The population of the County is
expected to increase over the next few years. With an increase in population, more people will be exposed to
winter weather events. Additionally, the age of the population, changes in their geography, and how climate
change could alter the winter weather received (rain versus snow) will be important to continue to assess future
changes in vulnerability.
Climate Change
Climate is defined not just as average temperature and precipitation, but also by type, frequency, and intensity
of weather events. Both globally and at the local level, climate change can potentially alter prevalence and
severity of weather extremes, such as winter storms. While predicting changes in winter storm events under a
changing climate is difficult, understanding vulnerabilities to potential changes is a critical part of estimating
future climate change impacts on human health, society, and the environment (U.S. EPA 2006). Based on the
projections, the County can expect to experience more rain than snow during the winter months. In the
immediate future, Galveston County can anticipate continuing to experience the impacts of winter weather
events.
Change of Vulnerability Since 2017 HMP
Galveston County’s population increased since the last plan; increasing the number of people impacted during a
winter weather event. Therefore, the entire County remains vulnerable to severe winter storm events.
Furthermore, the 2017 HMP did not include a quantitative analysis of impacts on building stock, considering it
negligible. However, a 1-percent exposure can result in $1.6 in damages. While winter weather is a rare
occurrence, they can occur and cause impacts.
4.3.13 Thunderstorm Wind
The following section provides the hazard profile and vulnerability assessment for the wind -related events
associated with thunderstorms in Galveston County.
Profile
Hazard Description
A thunderstorm is a storm with lightning and thunder produced by cumulonimbus clouds, usually producing
wind gusts, heavy rain, and sometimes hail or tornadoes (NWS n.d.). Thunderstorms are usually short-lived
(less than two hours), but they can deliver strong winds and enough rain to cause urban or flash flooding. The
NWS considers a thunderstorm severe only if it produces damaging wind gusts of 58 mph or higher or large hail
one inch (quarter size) in diameter or larger or tornadoes (NWS n.d.). Thunderstorms can occur at any time.
However, they usually occur during the spring and summer months and during the afternoon and evening. Severe
thunderstorms are most common from Texas to southern Minnesota; however, severe storms can occur anywhere
in the United States (NOAA n.d.).
It is estimated that each year there are 16 million thunderstorms worldwide. Approximately 100,000
thunderstorms occur in the United States each year (NSSL 2020). Figure 4-41 illustrates the average number of
days with thunderstorms using data from 1993 to 2018. This figure shows that Galveston County experiences
between 63 and 72 days of thunderstorms each year.
Section 4.3.13 - Thunderstorm Wind
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Figure 4-41. Annual Mean Thunderstorm Days, 1993-2018
Source: National Weather Service
Note: The approximate location of Galveston County is outlined in a red circle.
Thunderstorms can lead to flooding, landslides, strong winds, tornadoes, lightning, and hail. Roads could become
impassable from flooding, downed trees or power lines, or a landslide. Strong straight-line winds (up to more
than 12 mph) associated with thunderstorms can down trees and utility poles, causing utility outages.
Thunderstorms can create tornadoes with winds of up to 300 mph. Lightning can damage homes and injure
people. In the United States, an average of 300 people are injured and 80 people are killed by lightning each
year. Thunderstorms can produce hail up to the size of softballs damaging cars and windows, and killing
livestock caught out in the open (NOAA n.d.).
High winds are often associated by other severe weather events such as thunderstorms, tornadoes, hurricanes,
and tropical storms. Wind begins with differences in air pressures. It is usually horizontal movement of air
caused by the uneven heating of the Earth by the sun and the Earth's own rotation. Winds range from light
breezes to natural hazards (National Geographic Society 2021).
Location
Since thunderstorms can develop anywhere in the United States, all of Galveston County is exposed and
vulnerable to the impacts of thunderstorms.
Extent
Severe thunderstorm watches and warnings are issued by the local NWS office and the Storm Prediction Center
(SPC). The NWS and SPC will update the watches and warnings and notify the public when they are no longer
in effect. Watches and warnings for thunderstorms in Galveston County are as follows:
Section 4.3.13 - Thunderstorm Wind
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• Severe Thunderstorm Warnings are issued when there is evidence based on radar or a reliable spotter
report that a thunderstorm is producing, or forecast to produce, wind gusts of 58 mph or greater,
structural wind damage, or hail one inch in diameter or greater. A warning will include where the storm
was located, what municipalities will be impacted, and the primary threat associated with the severe
thunderstorm warning. After it has been issued, the NWS office will follow up periodically with Severe
Weather Statements that contain updated information on the severe thunderstorm and advise the public
when the warning is no longer in effect (NOAA NWS 2009).
• Severe Thunderstorm Watches are issued by the SPC when conditions are favorable for the development
of severe thunderstorms over a larger-scale region for a duration of at least three hours. Tornadoes are
not expected in such situations, but isolated tornado development can also occur. A Severe
Thunderstorm Watch is issued when an organized episode of hail 1 inch diameter or larger and/or
damaging thunderstorm winds are expected during a two-to-eight-hour period. During the watch, the
NWS will keep the public informed on what is happening in the watch area and also advise public when
the watch has expired or been cancelled (SPC 2021) (NOAA NWS 2009).
Figure 4-42 presents the severe thunderstorm risk categories, as provided by the SPC.
Figure 4-42. Severe Thunderstorm Risk Categories.
Source: SPC 2020
Winds associated with thunderstorms are measured according to the Beaufort Wind Scale, as outlined in Table
4-68. This scale was one of the first to estimate wind speeds. It starts with 0 and goes to a force of 12.
Table 4-68. Beaufort Wind Scale
Force Wind (Knots) WMO Classification Appearance of Wind Effects on Land
0 Less than 1 Calm Calm, smoke rises vertically
1 1-3 Light Air Smoke drift indicates wind direction, still wind vanes
2 4-6 Light Breeze Wind felt on face, leaves rustle, vanes begin to move
3 7-10 Gentle Breeze Leaves and small twigs constantly moving, light flags extended
4 11-16 Moderate Breeze Dust, leaves, and loose paper lifted; small tree branches move
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-132
2022 Update
Force Wind (Knots) WMO Classification Appearance of Wind Effects on Land
5 17-21 Fresh Breeze Small trees in leaf begin to sway
6 22-27 Strong Breeze Larger tree branches moving, whistling in wires
7 28-33 Near Gale Whole trees moving, resistance felt walking against wind
8 34-40 Gale Twigs breaking off trees, generally impedes progress
9 41-47 Strong Gale Slight structural damage occurs, slate blows off roofs
10 48-55 Storm Seldom experienced on land, trees broken, or uprooted, considerable
structural damage occurs
11 56-63 Violent Storm If experienced on land, widespread damage
12 64+ Hurricane Violence and destruction
Source: (NWS n.d.)
The NWS issues advisories and warnings for winds. Issuance is normally site-specific. High wind advisories,
watches, and warnings are products issued by the NWS when wind speeds can pose a hazard or are life
threatening. The criterion for each of these varies from state to state. According to the NWS, wind warnings and
advisories for Galveston County are as follows:
• High Wind Warnings are issued when sustained wind speeds of 40 mph or greater lasting for one hour
or longer or for wind gusts of 58 mph or greater for any duration.
• Wind Advisories are issues when sustained winds of 31 to 39 mph are forecast for one hour or longer,
or wind gusts of 46 to 57 mph for any duration (NWS n.d.).
Worst-Case Scenario
A worst-case scenario would involve prolonged high winds of 85 mph, Force 12 on the Beaufort Wind Scale,
during a thunderstorm event. This type of event would have both a short- and long-term effects on Galveston
County. The strong winds would lead to downed trees and power lines, creating road closures and countywide
power outages. Parts of the County could experience limited ingress and egress.
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
thunderstorms in Galveston County. According to the NOAA-NCEI Storm Events Database, there were 203
thunderstorm wind events recorded in Galveston County between 1950 and November 2021. Damages reported
for these events totaled over $53 million (refer to Table 4-69).
Table 4-69. Thunderstorm Wind Events in Galveston County, 1950-2021
Hazard Type
Number of
Occurrences
Between 1950
and 2021 Total Fatalities Total Injuries
Total Property
Damage ($)
Total Crop
Damage ($)
Thunderstorm Wind 203 0 7 $53,133,000 $8,500
Source: NOAA-NCEI 2021
Note: Due to limitations in data, not all thunderstorm wind events occurring between 1950 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated
Between 1953 and 2021, the State of Texas was included in seven thunderstorm-related FEMA major disaster
(DR) or emergency (EM) declarations. Of those declarations, Galveston County was included in two
declarations. Table 4-70 lists FEMA DR and EM declarations for Galveston County.
Table 4-70. Thunderstorm-Related FEMA Declarations for Galveston County, 1953 to 2021
FEMA Declaration
Number Date(s) of Event Incident Type Incident Title
DR-1041 October 14-November 8, 1994 Flood Severe Thunderstorms and Flooding
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-133
2022 Update
FEMA Declaration
Number Date(s) of Event Incident Type Incident Title
DR-4245 October 22-31, 2015 Severe Storm Severe Storms, Tornadoes, Straight-
line Winds, and Flooding
Source: FEMA 2021
For the 2022 HMP update, known thunderstorm wind events were summarized from 2016 to 2021 (see Table
4-71). For events prior to 2016, refer to the 2017 Galveston County HMP. For detailed information on damages
and impacts to each municipality, refer to Section 9 (Jurisdictional Annexes). The events listed in Table 4-71
represent only those that were reported to the NOAA-NCEI Storm Events Database and FEMA and may not
represent all events that occurred or impacted the County since 2016.
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-134
2022 Update
Table 4-71. Thunderstorm Wind in Galveston County, 2016 to 2021
Date(s) of
Event Event Type
FEMA
Declaration
Number
(if
applicable)
County
Designated?
Magnitude
(wind
speed in
knots) Fatalities Injuries Damages Event Details*
February 14,
2017
Thunderstorm
Wind - - 52 0 0 $4000 Six power poles were blown down near the intersection
of Highway 87 and Helen Blvd.
February 14,
2017
Thunderstorm
Wind - - 53 0 0 $12000 A couple of trees were downed (one on a house) along
Avenue I between 21st Street and 24th Street.
February 14,
2017
Thunderstorm
Wind - - 53 0 0 $4000 Power poles were snapped at Crenshaw Elementary
School.
October 20,
2017
Thunderstorm
Wind - - 50 0 0 $0 Damage was reported near the intersection of FM 646
and Highway 3.
March 29,
2018
Thunderstorm
Wind - - 50 0 0 $1000 There was some minor residential awning and tree limb
damage.
March 29,
2018
Thunderstorm
Wind - - 50 0 0 $0
An oleander tree was knocked down and a wooden
bench swing collapsed around the intersection of 15th
Street and Avenue M.
March 29,
2018
Thunderstorm
Wind - - 52 0 0 $1000 A power pole was downed near an apartment complex
on 21st Street.
June 9, 2018 Thunderstorm
Wind - - 52 0 0 $3000 Numerous trees were downed off of Gordy Road.
October 31,
2018
Thunderstorm
Wind - - 56 0 0 $0
Thunderstorm winds caused minor structure damage.
Winds rolled over an exposed, non-anchored mobile
trailer off of Dike Drive.
October 31,
2018
Thunderstorm
Wind - - 50 0 0 $0 Thunderstorm winds downed two palm trees on
Harborside Drive and 29th Street.
October 31,
2018
Thunderstorm
Wind - - 52 0 0 $0 There was a report of a collapsed residence on Ave S
and 47th street.
January 19,
2019
Thunderstorm
Wind - - 50 0 0 $15000
Trees and fences were downed and there were damaged
and destroyed trampolines, gazebos, barn roofs and
retail signs.
April 7, 2019 Thunderstorm
Wind - - 53 0 0 $0 There were trees blown down.
April 7, 2019 Thunderstorm
Wind - - 52 0 0 $0 There were trees downed.
April 7, 2019 Thunderstorm
Wind - - 55 0 0 $7000 Some travel trailers were flipped over.
May 9, 2019 Thunderstorm
Wind - - 55 0 0 $0 There were reports of trees and power lines downed
along Highway 96 just west of Highway 3.
May 9, 2019 Thunderstorm
Wind - - 55 0 0 $0 Thunderstorm winds damaged the roof of the volunteer
fire department.
June 29,
2019
Thunderstorm
Wind - - 60 0 0 $0
A large area of the Bolivar Peninsula was without
power after strong thunderstorm wind gusts were
observed.
May 27,
2020
Thunderstorm
Wind - - 56 0 0 $11000 There was some roof damage to a Texas City business.
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-135
2022 Update
Date(s) of
Event Event Type
FEMA
Declaration
Number
(if
applicable)
County
Designated?
Magnitude
(wind
speed in
knots) Fatalities Injuries Damages Event Details*
May 27,
2020
Thunderstorm
Wind - - 56 0 0 $5500 Large tree limbs and some fencing were blown down.
May 27,
2020
Thunderstorm
Wind - - 61 0 0 $0 The wind gust was measured at KGLS.
April 23,
2021
Thunderstorm
Wind - - 50 0 0 $0 Local emergency managers reported a travel trailer
knocked over by strong thunderstorm wind gusts.
Source(s): FEMA 2021; NOAA-NCEI 2021
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact information may vary and has been summarized in the above table
- Not available/not recorded
FEMA Federal Emergency Management Agency
NCEI National Centers for Environmental Information
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-136
2022 Update
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016). Major clusters of summertime thunderstorms in
North America will grow larger, more intense, and more frequent later this century in a changing climate, leading
to increased rainfall and posing a greater threat of flooding across wide areas (UCAR 2017).
Probability of Future Occurrences
Table 4-72 summarizes data regarding the probability of occurrences of thunderstorm events in Galveston
County based on the historic record. The information used to calculate the probability of occurrences is based
on the 2017 Galveston County HMP, the NOAA-NCEI Storm Events Database, and FEMA.
Table 4-72. Probability of Future Occurrence of Thunderstorm Events
Hazard Type
Number of Occurrences Between
1950 and 2021
% chance of occurrence in any
given year
Thunderstorm Wind 205 100%
Source: NOAA-NCEI 2021; FEMA 2021; Galveston County HMP 2017
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected thunderstorm wind
events since 1968. Due to limitations in data, not all thunderstorm wind events occurring between 1954 and 1996 are accounted for in
the tally of occurrences. As a result, the number of hazard occurrences is underestimated.
Galveston County is expected to continue experiencing the direct and indirect impacts of thunderstorms each
year. Over 200 thunderstorm wind events were recorded in 71 years, giving the County a 100% chance of being
impacted by a thunderstorm in any given year. However, based on historical records and input from the Steering
Committee, the probability of occurrence for thunderstorm wind events in the County is considered frequent
(100% chance occurring; occurs multiple times a year). Refer to Section 4.4 for additional information on the
hazard ranking methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the thunderstorm hazard; therefore, all assets within
the County (population, structures, critical facilities, and lifelines), as described in Section 3 (County Profile),
are potentially vulnerable to a thunderstorm event. The following text evaluates and estimates the potential
impact of the thunderstorm hazard in the County.
Impact on Life, Health and Safety
The most common problems associated with thunderstorms are immobility and loss of utilities. Although the
entire population of the County is exposed to thunderstorms, some populations are more vulnerable. Vulnerable
populations include the elderly, low income, linguistically isolated populations, people with life-threatening
illnesses, and residents living in areas that are isolated from major roads. Power outages can be life threatening
to those dependent on electricity for life support. In general, populations who lack adequate shelter during a
thunderstorm, those who are reliant on sustained sources of power in order to survive, and those who live in
isolated areas with limited ingress and egress options are the most vulnerable.
The impact of thunderstorms on life, health, and safety is dependent upon several factors including the severity of
the event and whether adequate warning time was provided to residents. The entire population of Galveston
County (350,682) is assumed to be exposed to this hazard (2015-2019 ACS 5-Year Population Estimate).
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-137
2022 Update
People located outdoors (i.e., recreational activities and farming) are considered most vulnerable to hailstorms,
thunderstorms, and tornadoes because there is little to no warning, and shelter might not be available. Moving
to a lower risk location will decrease a person’s vulnerability.
As a result of severe weather events, residents can be displaced or require temporary to long-term sheltering.
The HAZUS-MH results for the 100-year and 500-year MRP hurricane wind events are able to show displaced
households and people requiring short-term sheltering. 5,769 households will be displaced, and 3,725 people
will require short-term sheltering in the 100-year event. 25,021 households will be displaced, and 16,068 people
will require short-term sheltering in the 500-year event.
Table 4-73. Displaced Households and Short-Term Sheltering
Jurisdiction
100-Year Mean Return Period
Hurricane
500-Year Mean Return Period
Hurricane
Displaced
Households
Persons Seeking
Short-Term
Sheltering
Displaced
Households
Persons Seeking
Short-Term
Sheltering
Bayou Vista (C) 36 15 125 52
Clear Lake Shores (C) 52 21 231 94
Dickinson (C) 284 207 1,458 1,054
Friendswood (C) 270 145 1,410 756
Hitchcock (C) 88 62 409 286
Jamaica Beach (C) 9 4 30 13
Kemah (C) 72 44 236 139
La Marque (C) 239 164 1,137 790
League City (C) 1,152 638 6,500 3,697
Santa Fe (C) 218 130 1,042 618
Tiki Island (V) 23 10 80 33
Galveston County (Total) 5,769 3,725 25,021 16,068
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Economically disadvantaged populations are more vulnerable because they often evaluate evacuation needs and
make decisions based on the economic impact to their family. The population over the age of 65 (46,103) is also
vulnerable, can physically have difficulty evacuating, and are more likely to seek or need medical attention, which
may not be available due to isolation during a storm event (U.S. Census 2019 ACS 5-Year Population Estimate).
Section 3 (County Profile) provides for the statistics for these populations for Galveston County.
Impact on General Building Stock
Damage to buildings is dependent upon several factors, including wind speed, storm duration, and path of the
storm track. Building construction also plays a major role in the extent of damage resulting from a storm. Due
to differences in construction, residential structures are generally more susceptible to wind damage than
commercial and industrial structures. Wood and masonry buildings, in general, regardless of their occupancy
class, tend to experience more damage than concrete or steel buildings.
To better understand these risks, Hazus was used to estimate the expected wind-related building damages.
Specific types of wind damages are also summarized in Hazus at the following wind damage categories: no
damage/very minor damage, minor damage, moderate damage, severe damage, and total destruction. Table 4-74
summarizes the definition of the damage categories.
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-138
2022 Update
Table 4-74. Description of Damage Categories
Qualitative Damage Description
Roof
Cover
Failure
Window
Door
Failures
Roof
Deck
Missile
Impacts
on
Walls
Roof
Structure
Failure
Wall
Structure
Failure
No Damage or Very Minor Damage
Little or no visible damage from the outside.
No broken windows, or failed roof deck.
Minimal loss of roof over, with no or very
Limited water penetration.
≤2% No No No No No
Minor Damage
Maximum of one broken window, door, or
garage door. Moderate roof cover loss that
can be covered to prevent additional water
entering the building. Marks or dents on
walls requiring painting or patching for
repair.
>2% and
≤15%
One
window,
door, or
garage door
failure
No <5
impacts
No No
Moderate Damage
Major roof cover damage, moderate window
breakage. Minor roof sheathing failure.
Some resulting damage to interior of
building from water.
>15%
and
≤50%
> one and ≤
the larger of
20% & 3
1 to 3
panels
Typically
5 to 10
impacts
No No
Severe Damage
Major window damage or roof sheathing
loss. Major roof cover loss. Extensive
damage to
interior from water.
>50% > the larger
of 20% & 3
and ≤50%
>3 and
≤25%
Typically
10 to 20
impacts
No No
Destruction
Complete roof failure and/or, failure of wall
frame. Loss of more than 50% of roof
sheathing.
Typically
>50%
>50% >25% Typically
>20
impacts
Yes Yes
Table 4-75. Estimated Losses for the 100-Year MRP Hurricane Wind Events
Jurisdiction
Building
Replacement Cost
Value
Estimated Building
Losses Caused by
the 100-Year Mean
Return Period
Hurricane
Percent of
Total
Estimated Building
Losses Caused by
the 100-Year Mean
Return Period
Hurricane for
Residential
Structures Only
Estimated Building
Losses Caused by
the 100-Year Mean
Return Period
Hurricane for
Commercial
Structures Only
Bayou Vista (C) $287,902,599.47 $36,983,852 12.8% $30,661,401 $4,810,433
Clear Lake Shores (C) $519,006,216.88 $53,521,768 10.3% $44,602,868 $8,161,448
Dickinson (C) $3,924,480,999.53 $288,661,121 7.4% $200,469,958 $56,870,394
Friendswood (C) $6,532,042,745.35 $406,504,909 6.2% $336,560,004 $53,763,471
Hitchcock (C) $2,606,611,538.31 $158,617,043 6.1% $91,124,991 $49,025,770
Jamaica Beach (C) $292,462,937.69 $31,500,492 10.8% $26,697,522 $4,078,968
Kemah (C) $1,410,211,778.23 $96,243,976 6.8% $54,140,360 $37,997,929
La Marque (C) $4,518,194,733.81 $312,776,831 6.9% $194,440,522 $70,454,482
League City (C) $18,876,791,173.65 $1,389,159,281 7.4% $1,127,306,904 $201,230,703
Santa Fe (C) $2,826,459,977.04 $252,241,130 8.9% $171,659,441 $38,509,804
Tiki Island (V) $240,413,556.57 $23,596,649 9.8% $19,570,959 $3,059,031
Galveston County (Total) $96,229,561,611.86 $8,513,160,224 8.8% $5,339,350,583 $2,253,000,595
Source: Hazus-MH 4.2
Notes: MRP = Mean return period
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-139
2022 Update
Impact on Critical Facilities
Overall, all critical facilities in Galveston County are vulnerable to being affected by thunderstorms. Utility
infrastructure could suffer damage from high winds associated with falling tree limbs or other debris, resulting
in the loss of power or other utility service. Loss of service can impact residents, critical facilities, and business
operations alike. Interruptions in heating or cooling utilities can affect populations, such the young and elderly,
who are particularly vulnerable to temperature-related health impacts. Loss of power can impact other public
utilities, including potable water, wastewater treatment, and communications. In addition to public water
services, property owners with private wells might not have access to potable water until power is restored. Lack
of power to emergency facilities, including police, fire, EMS, and hospitals, will inhibit a community’s ability
to effective respond to an event and maintain the safety of its citizens.
Hazus estimates that critical facilities in Galveston County have a low percent probability of sustaining minor
to moderate damages from the 100-year MRP hurricane wind event. Hazus also estimates that there are critical
facilities that have a 65.8-percent probability of sustaining severe damage from the 500-year MRP hurricane
wind event. These probabilities can be found in Table 4-76 and Table 4-77 by facility type.
Table 4-76. Estimated Impacts to Critical Facilities for the 100-Year MRP Hurricane Wind Event
Facility Type
100-Year Mean Return Period Hurricane
Loss of Days
Percent-Probability of Sustaining Damage
Minor Moderate Severe Complete
EOC 0 18.1% - 23.3% 24.1% - 30.6% 10.2% - 29.8% 0.0%
Medical Facilities 1 - 6 10.3% - 15.1% 29.7% - 41.8% 3.4% - 17.3% <0.1% - 1.3%
Police Stations 0 16.3% - 23.4% 22.4% - 30.7% 9.0% - 35.1% 0.0% - <0.1%
Fire Stations/EMS 0 11.0% - 14.9% 16.5% - 30.1% 4.3% - 23.3% 0.1% - 2.1%
Schools 7 - 70 3.7% - 10.2% 38.3% - 47.7% 5.3% - 33.3% <0.1% - 0.1%
Source: Hazus-MH v4.2
Table 4-77. Estimated Impacts to Critical Facilities for the 500-Year MRP Hurricane Wind Event
Facility Type
500-Year Mean Return Period Hurricane
Loss of Days
Percent-Probability of Sustaining Damage
Minor Moderate Severe Complete
EOC 0 - 4 12.0% - 15.3% 29.2% - 31.1% 38.0% - 47.0% <0.1%
Medical Facilities 6 - 31 4.2% - 10.5% 35.5% - 42.0% 16.8% - 40.6% 1.0% - 5.7%
Police Stations 0 - 1 7.9% - 19.6% 24.2% - 31.2% 26.6% - 60.6% 0.0% - 0.1%
Fire Stations/EMS 0 - 1 2.5% - 12.2% 20.8% - 32.6% 17.1% - 50.3% 1.1% - 19.4%
Schools 35 - 310 2.1% - 5.8% 10.7% - 46.1% 22.5% - 65.8% 0.3% - 16.5%
Source: Hazus-MH v4.2
Impact on Economy
Thunderstorm events can impact the economy of the County. Impacts include loss of business function, damage
to inventory, relocation costs, wage loss, and rental loss due to the repair or replacement of buildings. Business
interruption losses include losses associated with the inability to operate a business because of the wind damage
sustained during a storm or the temporary living expenses for those displaced from their home because of an
event.
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-140
2022 Update
Impacts to transportation lifelines affect both short-term (e.g., evacuation activities) and long-term (e.g., day-to-
day commuting and goods transport) transportation needs. Utility infrastructure (power lines, gas lines, electrical
systems) could suffer damage and impacts can result in the loss of power, which can impact business operations
and can impact heating or cooling provision to the population.
Hazus estimates the total economic loss associated with each storm scenario (direct building losses and business
interruption losses). Direct building losses are the estimated costs to repair or replace the damage caused to the
building. This is reported in the “Impact on General Building Stock” section discussed earlier. Business
interruption losses are the losses associated with the inability to operate a business because of the wind damage
sustained during the storm or the temporary living expenses for those displaced from their home because of the
event.
Debris management can be costly and may also impact the local economy. Hazus estimates the amount of
building and tree debris that may be produced as result of the 100- and 500-year MRP wind events. Because the
estimated debris production does not include flooding, this is likely a conservative estimate and may be higher
if multiple impacts occur. According to the Hazus Hurricane User Manual, estimates of weight and volume of
eligible tree debris consist of downed trees that would likely be collected and disposed at public expense. Refer
to the User Manual for additional details regarding these estimates. Table 4-78 and Table 4-79 summarizes debris
production estimates for the 100- and 500-year MRP wind events.
Table 4-78. Estimated Debris Created During the 100-Year Mean Return Period Hurricane Wind Event
Jurisdiction
Estimated Debris Created During the 100-Year Mean Return Period Hurricane Wind
Event**
Brick and Wood
(Tons)
Concrete and Steel
(Tons) Tree (Tons)
Eligible Tree Volume
(Cubic Yards)
Bayou Vista (C) 13,342 57 0 0
Clear Lake Shores (C) 3,843 17 0 0
Dickinson (C) 234,729 732 0 0
Friendswood (C) 11,300 50 0 0
Hitchcock (C) 3,733 18 0 0
Jamaica Beach (C) 18,206 75 0 0
Kemah (C) 16,447 73 0 0
La Marque (C) 17,982 83 0 0
League City (C) 3,426 14 0 0
Santa Fe (C) 4,377 18 0 0
Tiki Island (V) 8,748 40 0 0
Galveston County
(Total)
21,256 85 0 0
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Table 4-79. Estimated Debris Created During the 500-Year Mean Return Period Hurricane Wind Event
Jurisdiction
Estimated Debris Created During the 500-Year Mean Return Period Hurricane Wind
Event**
Brick and Wood
(Tons)
Concrete and Steel
(Tons) Tree (Tons)
Eligible Tree Volume
(Cubic Yards)
Bayou Vista (C) 19,524 115 0 0
Clear Lake Shores (C) 7,120 52 0 0
Dickinson (C) 1,078,099 7,295 0 0
Friendswood (C) 17,059 106 0 0
Hitchcock (C) 12,292 125 0 0
Section 4.3.13 - Thunderstorm Wind
Galveston County, TX | Hazard Mitigation Plan 4-141
2022 Update
Jurisdiction
Estimated Debris Created During the 500-Year Mean Return Period Hurricane Wind
Event**
Brick and Wood
(Tons)
Concrete and Steel
(Tons) Tree (Tons)
Eligible Tree Volume
(Cubic Yards)
Jamaica Beach (C) 31,113 191 0 0
Kemah (C) 29,188 196 0 0
La Marque (C) 57,036 526 0 0
League City (C) 6,632 43 0 0
Santa Fe (C) 7,104 44 0 0
Tiki Island (V) 29,359 272 0 0
Galveston County
(Total)
42,147 265 0 0
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on the Environment
The impact of thunderstorm wind events on the environment varies, but researchers are finding that the long-
term impacts of more severe events can be destructive to the natural and local environment. National
organizations such as USGS and NOAA have been studying and monitoring the impacts of extreme weather
phenomena as it impacts long term climate change, streamflow, river levels, reservoir elevations, rainfall, floods,
landslides, erosion, etc. (USGS 2017). For example, severe weather that creates longer periods of rainfall can
erode natural banks along waterways and degrade soil stability for terrestrial species. Tornadoes can tear apart
habitats causing fragmentation across ecosystems. Researchers also believe that a greater number of diseases
will spread across ecosystems because of impacts that severe weather and climate change will have on water
supplies (NOAA 2013c). Overall, as the physical environment becomes more altered, species will begin to
contract or migrate in response, which may cause additional stressors to the entire ecosystem within Galveston
County.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. Areas
targeted for potential future growth and development could be potentially impacted by thunderstorms since the
entire County is exposed to the thunderstorm hazard. However, due to increased standards and codes, new
development can be less vulnerable to the thunderstorm hazard compared with the aging building stock in the
County.
Projected Changes in Population
The County experienced an increase in population between the 2010 Census (291,309) and the estimated 2015-
2019 American Community Survey estimated population of 350,682. The population of the County is expected
to increase over the next few years. The increase in population will expose more people to the thunderstorm
hazard.
Section 4.3.14 - Tornadoes
Galveston County, TX | Hazard Mitigation Plan 4-142
2022 Update
Climate Change
Major clusters of summertime thunderstorms in North America will grow larger, more intense, and more
frequent later this century in a changing climate, unleashing far more rain and posing a greater threat of flooding
across wide areas (UCAR 2017). An increase in storms will produce more wind events and may increase tornado
activity. Additionally, an increase in temperature will provide more energy to produce storms that generate
tornadoes (Climate Central 2016). Overall, Galveston County will continue to remain vulnerable to the
thunderstorm hazard.
Changes in Vulnerability Since the 2017 HMP
Overall, the County’s vulnerability has not changed, and the entire County will continue to be exposed and
vulnerable to thunderstorm wind events. As existing development and infrastructure continue to age, they can
be at increased risk to failed utility and transportation systems if they are not properly maintained and do not
adapt to the changing environment.
4.3.14 Tornadoes
The following section provides the hazard profile and vulnerability assessment for the tornado hazard in
Galveston County.
Profile
Hazard Description
A tornado appears as a rotating, funnel-shaped cloud that extends from a thunderstorm to the ground with
whirling winds that can reach 300 miles per hour. Damage paths can be greater than 1 mile wide and 50 miles
long. Tornadoes typically develop from either a severe thunderstorm or hurricane as cool air rapidly overrides a
layer of warm air. Tornadoes typically move at speeds between 30 and 125 mph and can generate combined
wind speeds (forward motion and speed of the whirling winds) exceeding 300 mph. Most tornadoes are on the
ground for less than 15 minutes (NWS n.d.). Tornadoes can occur at any time of the year, with peak season for
Texas from May into early June (NOAA n.d.). An average of 1,141 tornadoes occur in the United States each
year, based on tornadoes recorded between 1985 and 2014. The State of Texas averages 140 tornadoes each
year.
Section 4.3.14 - Tornadoes
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2022 Update
Figure 4-43. Average Annual Number of Tornadoes, 1985 to 2014
Source: SPC 2021
Location
Similar to that of thunderstorms, tornadoes do not have any specific geographic boundary and can occur
anywhere in Galveston County. According to the FEMA Winds Zones of the United States map, the County is
located in Wind Zones III, where wind speeds can reach up to 200 mph. Additionally, the County is located in
the hurricane-susceptible region. FEMA .
Figure 4-44 illustrates wind zones across the United States, which indicate the impacts of the strength and
frequency of wind activity per region. The information on the figure is based on 70 years of tornado data and
160 years of hurricane data collected by FEMA (FEMA 2021).
Section 4.3.14 - Tornadoes
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2022 Update
Figure 4-44. Wind Zones in the United States
Source: FEMA 2021
Note: The blue circle indicates the approximate location of Galveston County.
Extent
Damage from tornadoes can vary from minor damage that break tree limbs to massive damage demolishing
homes in its path. The type of damage depends on the intensity, size, and duration of the tornado. The magnitude
or severity of a tornado is categorized using the Enhanced Fujita Tornado Intensity Scale (EF Scale). This is the
scale now used exclusively for determining tornado ratings by comparing wind speed and actual damage. Figure
4-45 illustrates the relationship between EF ratings, wind speed, and expected tornado damage. Galveston
County can experience tornadoes ranking from EF0 to EF4.
Section 4.3.14 - Tornadoes
Galveston County, TX | Hazard Mitigation Plan 4-145
2022 Update
Figure 4-45. Explanation of EF-Scale Ratings
Source: (NWS n.d.)
The NWS issues tornado watches and warnings. A tornado watch is issued by the SPC in Norman, Oklahoma.
They are issued when conditions are favorable for the development of tornadoes in and close to the watch area.
Their size can vary depending on the weather situation. Watches are typically issued for a duration of four to
eight hours. A tornado warning is issued by the local NWS office and will include where the tornado was located
and what municipalities will be in its path. It is issued when a tornado is indicated by a radar or spotters.
Warnings are issued for a duration of 30 minutes (NWS 2020). The current average lead time for tornado
warnings is 13 minutes. Occasionally, tornadoes develop so rapidly, that little, if any, advance warning is
possible (NOAA 2011).
Worst-Case Scenario
A worst-case scenario would be an EF3 tornado crossing through Galveston County with 3-second wind gusts
ranging from 136 to 165 mph, causing severe damage. A tornado of this magnitude would tear off roofs and
tear down walls, uproot trees, and lift vehicles off the ground. This could lead to downed utility poles, street
signals, and debris on roadways, disrupting normal operations and impacting emergency response times. Critical
and essential facilities could also be impacts, resulting in periods of service disruption to residents due to facility
damages or lack of back-up power.
Section 4.3.14 - Tornadoes
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2022 Update
Previous Occurrences and Losses
Many sources have provided historical information regarding previous occurrences and losses associated with
tornadoes events in Galveston County. According to NOAA-NCEI Storm Events Database, Galveston County
has been impacted by 94 tornado events that caused one fatality, 9 injuries, and more than $3.4 million in
property damage.
Table 4-80. Tornado Events in Galveston County, 1996-2020
Hazard Type
Number of
Occurrences
Between 1996
and 2020
Total
Fatalities
Total
Injuries
Total Property
Damage ($)
Total Crop
Damage ($)
Funnel Cloud 52 0 0 $0 $0
Tornado 42 0 9 $3,413,500 $0
TOTAL 94 0 9 $3,413,500 million $0
Source: NOAA-NCEI 2021
Between 1953 and 2021, the State of Texas was included in 15 tornado-related FEMA major disaster (DR) or
emergency (EM) declarations. Of those declarations, Galveston County was not included in any of the
declarations. For the 2022 update, tornado events were summarized from 2016 to 2021 (see Table 4-81). For
events prior to 2016, refer to the 2017 Galveston County HMP. For detailed information on damages and impacts
to each municipality, refer to Section 9 (Jurisdictional Annexes).
Section 4.3.14 - Tornadoes
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2022 Update
Table 4-81 Tornado Events in Galveston County, 2016 to 2021
Date(s) of
Event Event Type
FEMA
Declaration
Number
(if applicable)
County
Designated? Fatalities Injuries Damages Event Details*
April 24, 2016 Tornado
(EF0)
N/A N/A 0 0 $100,000 An EF-0 tornado produced intermittent damage that began
southwest of a Cabela’s parking lot then continued east across
Interstate 45 and then on toward the NE across a Candlewood
Suites hotel and an assisted living center. The tornado continued
north-northeast through the Victory Lakes subdivision then to near
Lynn Nursery along Pecan Orchard Road where they were some
minor tree damage. Vehicles were damaged by swirling winds and
debris around the Cabela’s and the Candlewood Suites sustained
roof damage. In area neighborhoods, damage was mostly minor
with numerous fences down and loose objects like basketball goals
and trampolines knocked over. One storage shed in Victory Lakes
was picked up and thrown approximately 300 yards.
July 17, 2016 Tornado
(EF0)
N/A N/A 0 0 0 A waterspout moved onshore and became a weak tornado just east
of the Galveston Fishing Pier at 61st Street. The tornado moved
across Seawall Boulevard and dissipated. There was no damage.
July 20, 2016 Funnel
Cloud
N/A N/A - - - A League City area funnel cloud lasted around fifteen minutes.
February 17,
2017
Funnel
Cloud
N/A N/A - - - A funnel cloud that was sighted over the city became a waterspout
when it moved into Galveston Bay.
May 22, 2017 Tornado
(EF0)
N/A N/A 0 0 $20,000 An EF0 tornado damaged a Holiday Inn along Termini-San Luis
Pass Road. Damage included blown out windows and lattice
damage. Witnesses indicated this was a waterspout that moved
onshore.
August 18,
2017
Funnel
Cloud
N/A N/A - - - A funnel cloud was observed near Harborside Drive on Galveston
Island.
August 18,
2017
Funnel
Cloud
N/A N/A - - - A second funnel cloud was observed near Harborside Drive on
Galveston Island.
August 25,
2017
Tornado
(EF0)
N/A N/A 0 0 $500 Funnel cloud sighting with fence damage near Ferry Road.
August 27,
2017
Tornado
(EF0)
N/A N/A 0 0 $200,000 Trees down, minor roof damage in Bacliff. Fences down.
October 20,
2017
Tornado
(EF0)
N/A N/A 0 0 $50,000 An EF0 tornado downed trees and branches along either side of
Benson's Bayou. Damage included home and vehicle windows
along with residential fences.
May 4, 2019 Tornado
(EF0)
N/A N/A 0 0 $10,000 Brief touchdown. Peeled off tin roof, damaged manufactured home
and storage shed.
May 27, 2020 Funnel
Cloud
N/A N/A - - - A funnel cloud was sighted.
Section 4.3.14 - Tornadoes
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2022 Update
Date(s) of
Event Event Type
FEMA
Declaration
Number
(if applicable)
County
Designated? Fatalities Injuries Damages Event Details*
May 29, 2020 Funnel
Cloud
N/A N/A - - - A funnel cloud was observed over the Bolivar Peninsula.
Source(s): FEMA 2021; NOAA-NCEI 2021; Galveston County HMP 2017
* Many sources were consulted to provide an update of previous occurrences and losses; event details and loss/impact information may vary and has been summarized in the above table
- Not reported/not available
FEMA Federal Emergency Management Agency
HMP Hazard Mitigation Plan
NCEI National Centers for Environmental Information
Section 4.3.14 - Tornadoes
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2022 Update
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016). An increase in storms will produce more wind
events and may increase tornado activity. However, the link between tornadoes and climate change is unclear
(Center for Climate and Energy Solutions n.d.).
Probability of Future Occurrences
Table 4-82 summarizes data regarding the probability of occurrences of tornado events in Galveston County
based on the historic record. The information used to calculate the probability of o ccurrences is based on the
2017 Galveston County HMP, the NOAA-NCEI storm events database, and FEMA.
Table 4-82. Probability of Future Occurrence of Tornado Events
Hazard Type
Number of Occurrences Between 1996
and 2021
% chance of occurrence in any
given year
Funnel Cloud 52 100%
Tornado (all magnitudes) 42 100%
TOTAL 94 100%
Source: NOAA-NCEI 2021; Galveston County HMP 2017, FEMA
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected tornado events
since 1968. Due to limitations in data, not all tornado events occurring between 1954 and 1996 are accounted for in the tally of
occurrences. As a result, the number of hazard occurrences is underestimated.
Galveston County is expected to continue experiencing the direct and indirect impacts of tornadoes each year.
The County experienced ninety-four tornado and funnel cloud incidents in 24 years, giving the County a 100%
chance of being impacted by a tornado of any magnitude in any given year. Based on historical records and
input from the Steering Committee, the probability of occurrence for tornadoes in Galveston County is
considered frequent (100% chance occurring; occurs multiple times a year). Refer to Section 4.4 for additional
information on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the tornado hazard; therefore, all assets within the
County (population, structures, critical facilities, and lifelines), as described in Section 3 (County Profile), are
potentially vulnerable to a thunderstorm event. The following text evaluates and estimates the potential impact
of the tornado hazard in the County.
Impact on Life, Health and Safety
Impacts of a tornado on life, health, and safety depend on several factors, including severity of the event and
whether adequate warning time was provided to residents. All residents in Galveston County are exposed to the
tornado hazard.
Residents impacted by tornadoes may be displaced or require temporary to long-term sheltering. In addition,
downed trees, damaged buildings, and debris carried by winds associated with tornadoes can lead to injury or
loss of life. Similar to other natural hazards, socially vulnerable populations are most susceptible, based on a
number of factors including their physical and financial ability to react or respond during a hazard and locations
and construction quality of their housing. Economically disadvantaged populations are more vulnerable because
Section 4.3.14 - Tornadoes
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2022 Update
they are likely to evaluate their risk and make decisions based on the major economic impact on their family and
may not have funds to evacuate. The population over the age of 65 is also more vulnerable and, physically, they
may have more difficulty evacuating. The elderly are considered most vulnerable because they require extra
time or outside assistance during evacuations and are more likely to seek or need medical attention that may not
be available due to isolation during a storm event. Section 3 (County Profile) presents the statistical information
regarding these populations in the County.
Impact on General Building Stock
The entire County’s building stock is exposed to the tornado hazard. Damage to buildings depends on several
factors, including wind speed, storm duration, path of the storm track or tornado, and distance from the tornado
funnel.
Manufactured housing (i.e. mobiles homes) is particularly vulnerable to high winds and tornadoes. The U.S.
Census Bureau defines manufactured homes as “movable dwellings, 8 feet or wider and 40 feet or more long,
design to be towed on its own chassis, with transportation gear integral to the unit when it leaves the factory, and
without need of a permanent foundation (Census, 2010).” They can include multi-wides and expandable
manufactured homes but exclude travel trailers, motor homes, and modular housing. Due to their light-weight
and often unanchored design, manufactured housing is extremely vulnerable to high winds and will generally
sustain the most damage.
Impact on Critical Facilities
Utility infrastructure could suffer damage from tornadoes associated with falling tree limbs or other debris,
resulting in the loss of power or other utility service. Loss of service can impact residents, critical facilities, and
business operations alike. Interruptions in heating or cooling utilities can affect populations, such the young and
elderly, who are particularly vulnerable to temperature-related health impacts. Loss of power can impact other
public utilities, including potable water, wastewater treatment, and communications. In addition to public water
services, property owners with private wells might not have access to potable water until power is restored. Lack
of power to emergency facilities, including police, fire, EMS, and hospitals, will inhibit a community’s ability
to effective respond to an event and maintain the safety of its citizens.
Impact on Economy
Tornados also impact the economy, including loss of business function (e.g., tourism, recreation), damage to
inventory, relocation costs, and wage loss and rental loss due to repair/replacement of buildings. Impacts on
transportation lifelines affect both short-term (e.g., evacuation activities) and long-term (e.g., day-to-day
commuting and goods transport) transportation needs. Utility infrastructure (power lines, gas lines, electrical
systems) could sustain damage, and impacts could result in loss of power, which can affect business operations
and provision of heating or cooling to the population.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Section 4.3.15 - Tsunami
Galveston County, TX | Hazard Mitigation Plan 4-151
2022 Update
Projected Development
Any areas of growth could be potentially impacted by the tornado hazard because the entire County is exposed
and vulnerable. Residential development, specifically manufactured homes, may be considered more vulnerable
to the tornado hazard.
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2015-2019 American Community Survey estimated population of 350,682. The population of the County is
expected to increase over the next few years. The increase in population will expose more people to the tornado
hazard.
Climate Change
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. In the eastern two-thirds of the State, average annual rainfall is increasing; however, the soil is
becoming drier. Rainstorms are more intense, and floods are becoming more severe. In the coming decades,
storms are likely to become more severe in Texas (EPA 2016). An increase in storms will produce more wind
events and may increase tornado activity. Additionally, an increase in temperature will provide more energy to
produce storms that generate tornadoes (Climate Central 2018). With an increased likelihood of strong winds
and tornado events, all of the County’s assets will experience additional risk for losses as a result of extreme
wind events.
Changes in Vulnerability Since the 2017 HMP
The County’s population increased since the last plan, increasing the number of people vulnerable during a
tornado. Therefore, the entire County remains vulnerable to tornado events.
4.3.15 Tsunami
The following section provides the hazard profile and vulnerability assessment for the tsunami hazard for
Galveston County.
Profile
Hazard Description
A tsunami is a series of high-energy waves that radiate outward like pond ripples from an area where a
generating event occurs, arriving at shorelines over an extended period. Tsunamis can be induced by earthquakes,
landslides, and submarine volcanic explosions. Tsunamis are typically classified as local or distant, depending
on the location of their source in comparison to where waves occur:
• The waves nearest to the generating source represent a local tsunami. Such events have minimal warning
time, leaving few options except to run to high ground after a strong, prolonged local earthquake.
Damage from the tsunami adds to damage from the triggering earthquake due to ground shaking, surface
faulting, liquefaction, and landslides.
• The waves far from the generating source represent a distant tsunami. Distant tsunamis may travel for
hours before striking a coastline, giving a community a chance to implement evacuation plans if a
warning is received.
In the open ocean, a tsunami may be only a few inches or feet high, but it can travel with speeds approaching
600 miles per hour. As a tsunami enters the shoaling waters near a coastline, its speed diminishes, its wavelength
decreases, and its height increases greatly. At the shoreline, tsunamis may take the form of a fast-rising tide, a
cresting wave, or a bore (a large, turbulent wall-like wave). The bore phenomenon resembles a step-like change
SECTION 4.3.15: Tsunami
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2022 Update
in the water level that advances rapidly (from 10 to 60 miles per hour). The first wave is usually followed by
several larger and more destructive waves.
The configuration of the coastline, the shape of the ocean floor, and the characteristics of advancing waves play
important roles in the destructiveness of the waves. Bays, sounds, inlets, rivers, streams, offshore canyons,
islands, and flood control channels may alter the level of damage. Offshore canyons can focus tsunami wave
energy, and islands can filter the energy. A tsunami wave entering a flood control channel could reach a mile or
more inland, especially if it enters at high tide. The orientation of the coastline determines whether the waves
strike head-on or are refracted from other parts of the coastline. A wave may be small at one point and much
larger at others. The inundation area for a tsunami event is often described as runup as illustrated in Figure 4-46.
Figure 4-46 Runup Distance and Height in Relation to the Datum and Shoreline
Source: (UNESCO 2007)
Location
Galveston County is not at a high risk from tsunami due to the local rarity of the geologic events that most often
generate these dangerous waves. However, according to the Regional Assessment of Tsunami Potential in the
Gulf of Mexico (USGS 2009), there is sufficient evidence to consider submarine landslides in the Gulf of Mexico
as a present‐day tsunami hazard, as there are clear observations of large landslides along the continental margin
of the Gulf. In this study hydrodynamic modeling of potential maximum tsunamis from landslide sources were
conducted for the East Breaks (EB) slide (south Texas) and for hypothetical slides along the Florida/Campeche
margin. Wave propagation yielded potential maximum tsunami run‐up of approximately 4 meters or 13 feet,
relative to mean sea level (Galveston County 2017). All of coastal Galveston County is exposed and vulnerable
to the potential impacts of tsunamis.
Extent
A tsunami’s size and speed, as well as the coastal area’s form and depth, affect the impact of the tsunami. At
some locations, the advancing turbulent wave front will be the most destructive part of the tsunami wave. In
other situations, the greatest damage will be caused by the outflow of water back to the sea between crests,
SECTION 4.3.15: Tsunami
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sweeping away items on the surface and undermining roads, buildings, bulkheads, and other structures. This
outflow action can carry enormous amounts of highly damaging debris, resulting in further destruction. Ships
and boats, unless moved away from shore, may be forced against breakwaters, wharves, and other craft, or be
washed ashore and left grounded after the withdrawal of the seawater (National Tsunami Warning Center 2021).
Worst-Case Scenario
While the probability of a tsunami is very low, a worst-case scenario would be a locally generated tsunami with
little warning time to evacuate. If such an event were to occur, low-lying coastal properties would be inundated
and the potential for injury or death would be significant, similar to a hurricane storm surge event.
Previous Occurrences and Losses
According to available records from the State of Texas 2018 HMP Update and FEMA, there have been no
reported tsunami incidents recorded for Galveston County, however a verified tsunami event exists in the NGDC
database. Resulting from an aftershock of an earthquake near Puerto Rico on October 11, 1918, a small wave
was recorded at the Galveston, Texas tide gage on October 24, 1918. The magnitude of the tsunami runup was
not reported (NRC n.d.).
Climate Change Projections
The impacts of global climate change on tsunami probability are unknown. Some scientists say that melting
glaciers could induce tectonic activity, inducing earthquakes. Other scientists have indicated that underwater
avalanches (also caused by melting glaciers), may also result in tsunamis. Even if climate change does not
increase the frequency with which tsunamis occur, it may result in more destructive waves. As sea levels continue
to rise, tsunami inundation areas would likely reach further into communities than current mapping indicates.
Probability of Future Occurrences
An analysis of historical data indicates a very low risk for future occurrences of a tsunami for Galveston County.
The probability of the future occurrence of a tsunami is unlikely, with the last definite occurrence in 1918, more
than 100 years ago. Based on the one historical occurrence, the probability of a future event is considered low
(not likely to occur in 100 years). Refer to Section 4.4 for additional information on the hazard ranking
methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard.
Tsunami-related vulnerability data was generated using a GIS analysis for the tsunami hazard. A probabilistic
assessment was conducted for a 322-foot buffer from evacuation routes to analyze the tsunami hazard and
provide a range of loss estimates.
Impact on Life, Health and Safety
The impact of a tsunami on life, health and safety is dependent upon several factors including the severity of the
event and whether or not adequate warning time was provided to residents. The populations in Galveston County
that would be most exposed to this type of hazard are those along beaches and low lying coastal areas. The Cities
of Hitchcock, Kemah, La Marque, and Santa Fe are considered at risk, as with the highest percentage of their
populations exposed to the tsunami hazard area (Table 4-83). Tsunamis can cause great loss of life and property
damage where they come ashore, and most deaths are the result of drowning. Associated risks include water
pollution, damaged gas lines, and flooding.
SECTION 4.3.15: Tsunami
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Table 4-83. Population Located within the Tsunami Hazard Area
Jurisdiction
Total Population (American
Community Survey 2015-
2019)
Estimated Population Located Within the Tsunami
Hazard Area
Number of People Within 322
Feet of Tsunami Evacuation Route
Percent of
Total
Bayou Vista (C) 1,763 11 0.6%
Clear Lake Shores (C) 1,258 0 0.0%
Dickinson (C) 20,847 16 0.1%
Friendswood (C) 41,213 0 0.0%
Hitchcock (C) 7,301 583 8.0%
Jamaica Beach (C) 1,078 0 0.0%
Kemah (C) 1,807 23 1.3%
La Marque (C) 18,030 241 1.3%
League City (C) 114,392 3 0.0%
Santa Fe (C) 12,735 247 1.9%
Tiki Island (V) 1,106 0 0.0%
Galveston County (Total) 350,682 1,255 0.4%
Source: Galveston County GIS 2021, American Community Survey 2019 (5-year estimates 2015-2019)
Note (1): The Tsunami hazard area it (evacuation areas plus high tide – 300 ft plus 22 ft). The tidal buffer area was 322 ft from the mapped
shoreline
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on General Building Stock
Similar to the population exposed, for the purposes of this planning effort, all general building stock, critical
facilities, and infrastructure are considered vulnerable to the tsunami hazard. However, the areas with the highest
vulnerability are those areas that are low-lying along the coastline located of the County, including the Cities of
Hitchcock, Kemah, La Marque, and Santa Fe. The impact of the waves and the scouring associated with debris
that may be carried in the water could be very damaging to structures located in the tsunami’s path. Structures
that would be most vulnerable are those located in the front line of tsunami impact and those that are structurally
unsound.
Roads are the primary resource for evacuation to higher ground before and during the course of a tsunami event.
Flooding caused by a tsunami will greatly impact this important component in the management of tsunami
related emergencies. Bridges exposed to tsunami events can be extremely vulnerable due to the forces
transmitted by the wave run up and by the impact of debris carried by the wave action. The forces of tsunami
waves can also impact above ground utilities by knocking down power lines and radio/cellular communication
towers. Power generation facilities can be severely impacted by both the velocity impact of the wave action and
the inundation of floodwaters (Humboldt County Hazard Mitigation Plan 2008).
Tsunamis may induce secondary hazards such as water quality and supply concerns, and public health concerns.
Impacts on the economy are difficult to quantify. As discussed above, losses include but are not limited to general
building stock damages, business interruption/closure, impacts to tourism and tax base to Galveston County.
Table 4-84 provides a summary of the building stock exposed to the tsunami hazard area in the County. The
City of Hitchcock’s building stock is most vulnerable to the tsunami hazard, as it has almost 19% of its building
stock located in the tsunami hazard area. However, most municipalities in the County could experience
secondary impacts from a tsunami.
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2022 Update
Table 4-84. Building Stock Located within the Tsunami Hazard Area
Jurisdiction
Total
Number of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located in the Tsunami
Hazard Area
Number of
Buildings
Located
Within 322
Feet of
Tsunami
Evacuation
Route
Percent
of Total
Total RCV of
Buildings
Within 322
Feet of
Tsunami
Evacuation
Route
Percent
of Total
Bayou Vista (C) 1,365 $445,354,087.33 30 2.2% $27,811,590 6.2%
Clear Lake Shores (C) 1,155 $904,562,368.66 1 0.1% $203,406 0.0%
Dickinson (C) 10,351 $6,601,710,645.63 25 0.2% $50,113,058 0.8%
Friendswood (C) 14,891 $10,815,456,384.12 0 0.0% $0 0.0%
Hitchcock (C) 5,452 $4,592,036,651.86 528 9.7% $867,463,601 18.9%
Jamaica Beach (C) 1,291 $458,205,838.82 0 0.0% $0 0.0%
Kemah (C) 1,634 $2,631,702,105.60 70 4.3% $241,918,493 9.2%
La Marque (C) 10,749 $7,927,292,522.28 192 1.8% $209,195,400 2.6%
League City (C) 46,742 $31,237,974,594.10 33 0.1% $197,929,274 0.6%
Santa Fe (C) 7,942 $4,831,628,162.13 335 4.2% $499,193,162 10.3%
Tiki Island (V) 868 $365,209,145.44 0 0.0% $0 0.0%
Galveston County (Total) 209,947 $166,321,604,688.46 1,722 0.8% $3,204,780,207 1.9%
Source: Galveston County GIS 2021, Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note (1): The Tsunami hazard area it (evacuation areas plus high tide – 300 ft plus 22 ft). The tidal buffer area was 322 ft from the mapped
shoreline
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on Critical Facilities
Utility infrastructure could suffer damage to high waves associated with tsunamis, resulting in the loss of power
or other utility service. Loss of service can impact residents, critical facilities, and business operations alike.
Interruptions in heating or cooling utilities can affect populations, such the young and elderly, who are
particularly vulnerable to temperature-related health impacts. Loss of power can impact other public utilities,
including potable water, wastewater treatment, and communications. In addition to public water services,
property owners with private wells might not have access to potable water until power is restored. Lack of power
to emergency facilities, including police, fire, EMS, and hospitals, will inhibit a community’s ability to effective
respond to an event and maintain the safety of its citizens. Furthermore, tsunamis can restrict transportation
routes, preventing residents from evacuating or emergency equipment from helping those in need. According to
Table 4-85, there are 234 lifelines in the County located within the 322-foot tsunami evacuation route.
Table 4-85. Critical Facilities Located within the Tsunami Hazard Area
FEMA Lifeline Category Number of Lifelines
Number of Lifelines Located
Within 322 Feet of Tsunami
Evacuation Route
Communications 111 13
Energy 598 4
Food, Water, Shelter 162 6
Hazardous Materials 68 1
Health and Medical 91 4
Safety and Security 405 13
Transportation 882 193
Galveston County (Total) 2,317 234
SECTION 4.3.15: Tsunami
Galveston County, TX | Hazard Mitigation Plan 4-156
2022 Update
Source: Galveston County GIS 2021 (322 buffer from evacuation routes)
Note: The Tsunami hazard area it (evacuation areas plus high tide – 300 ft plus 22 ft). The tidal buffer area was 322 ft from the mapped
shoreline
Impact on the Economy
Tsunamis impact the economy; with impacts including loss of business function, damage to inventory, relocation
costs, wage loss, and rental loss due to the repair or replacement of buildings. While a tsunami is expected to
negatively impact infrastructure, it is not a significant amount, only 1.9% of the replacement cost value of the
building stock. It is expected that the loss of life from a tsunami event would be much more damaging.
Table 4-86. Estimated Critical Facilities and Lifelines within 322 Feet of Tsunami Evacuation Route
Jurisdiction
Total CFs
Located in
Jurisdiction
Total
Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline
Facilities Located Within 322 Feet of
Tsunamic Evacuation Route
Critical
Facilities
Percent
of Total
Critical
Facilities Lifelines
Percent
of Total
Lifelines
Bayou Vista (C) 5 5 5 100.0% 5 100.0%
Clear Lake Shores (C) 24 24 0 0.0% 0 0.0%
Dickinson (C) 91 83 9 9.9% 9 10.8%
Friendswood (C) 96 82 0 0.0% 0 0.0%
Hitchcock (C) 214 212 38 17.8% 36 17.0%
Jamaica Beach (C) 11 11 0 0.0% 0 0.0%
Kemah (C) 15 14 6 40.0% 6 42.9%
La Marque (C) 121 107 29 24.0% 29 27.1%
League City (C) 321 283 29 9.0% 29 10.2%
Santa Fe (C) 135 128 42 31.1% 41 32.0%
Tiki Island (V) 7 7 0 0.0% 0 0.0%
Galveston County (Total) 2,437 2,317 237 9.7% 234 10.1%
Source: Galveston County GIS 2021, Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note (1): The Tsunami hazard area it (evacuation areas plus high tide – 300 ft plus 22 ft). The tidal buffer area was 322 ft from the mapped
shoreline
Note (2): The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on the Environment
All waterways and beaches would be exposed to the effects of a tsunami; inundation of water and introduction
of foreign debris could be hazardous to the environment. All wildlife inhabiting the area also is exposed.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
SECTION 4.3.16: Utility Failure
Galveston County, TX | Hazard Mitigation Plan 4-157
2022 Update
Projected Development
Any areas of growth could be potentially impacted by the tsunami hazard because the entire County is exposed
and vulnerable; however, due to increased standards and codes, new development can be less vulnerable to the
hazard compared with the aging building stock in the County.
Projected Changes in Population
The County has experienced an increase in population between the 2010 Census (291,309) and the estimated
2015-2019 American Community Survey estimated population of 350,682. The population of the County is
expected to increase over the next few years. The increase in population will expose more people to the tsunami
hazard.
Climate Change
The impacts of global climate change on tsunami probability are unknown. Some scientists say that melting
glaciers could induce tectonic activity, inducing earthquakes. Other scientists have indicated that underwater
avalanches (also caused by melting glaciers), may also result in tsunamis. Even if climate change does not
increase the frequency with which tsunamis occur, it may result in more destructive waves. As sea levels continue
to rise, tsunami inundation areas would likely reach further into communities than current mapping indicates.
Change of Vulnerability Since the 2017 HMP
Galveston County continues to be vulnerable to tsunamis. Tsunami models on building stock were not run for
the 2017 HMP; therefore, estimated losses were not populated. Furthermore, the population of the County has
increased, therefore exposing more people the hazard.
4.3.16 Utility Failure
The following section provides the hazard profile and vulnerability assessment for the utility failure hazard for
Galveston County.
Profile
Hazard Description
Power failure is defined as any interruption or loss of electrical service caused by disruption of power
transmission caused by accident, sabotage, natural hazards, or equipment failure (also referred to as a loss of
power or power outage). A significant power failure is defined as any incident of a long duration, which would
require the involvement of the local and/or state emergency management organizations to coordinate provision
of food, water, heating, cooling, and shelter.
Widespread power outages can occur without warning or as a result of a natural disaster. Generally warning
times will be short in the case of technological failure, such as a fire at a sub-station, traffic accident, human
error, or terrorist attack. In cases where a power failure is caused by natural hazards, greater warning time is
possible. For example, high wind events such as tornados and hurricanes often cause widespread power failure
and are often forecasted before they affect a community. Additionally, severe winter weather conditions such as
ice storms, blizzards, and snowstorms often cause power failure. Incidents such as these often have plenty of
warning time, thus power response crews can stage resources to prepare for power failure.
Power failures can lead to secondary hazards as well, leading to negative impacts on the health and safety of
residents.
Section 4.3.16: Utility Failure
Galveston County, TX | Hazard Mitigation Plan 4-158
2022 Update
• During periods of extreme heat or extreme cold, vulnerable populations such as the elderly and
medically frail can be affected and are susceptible to hypothermia or heat stroke. Additionally, power
failure can lead to food spoilage, which has negative impacts on public health.
• Residents who rely on electric medical devices such as home oxygen machines, medication nebulizers,
home dialysis, infusion pumps, and electric wheelchairs may face life-threatening situations if power
failure extends beyond the battery backup timeframe of their device (Huff 2021).
• Another secondary hazard that can result from power failure is a loss of communications capability by
first responders, which may in turn have negative impacts on public safety. Power outages can also lead
to instances of civil disturbance, including looting.
• Power interruptions at chemical handling plants are of particular concern because of the potential for a
chemical spill during restart (EPA 2001). Chemical spills in turn can have significant health and
environmental impacts.
• Wastewater and potable water utility interruption may occur as a result of a power failure. These critical
utilities are essential to community continuity and recovery. Their interruption of service may have
cascading economic and environmental impacts. Lack of power can prevent fuel pumps from operating
and lead to fuel shortages.
• Power failure may also lead to an increase in traffic accidents. Traffic accidents may increase because
of the lack of traffic control devices such as stoplights and railroad crossing advisory signals. Power
outages lasting a long duration will force law enforcement officials to man traffic control points to
prevent accidents.
Location
Power failures in Galveston County are usually localized and are usually the result of a natural hazard event
involving high winds. Power failure is particularly problematic for homes that are cooled or heated with
electricity. Widespread power outages during the summer and winter months can directly impact vulnerable
populations such as the elderly and medically frail. According to the 2019 American Community Survey 5-Year
Estimates, 51.6 percent of homes across Galveston County are heated with electricity.
Wastewater treatment for most municipalities is provided by municipal or private treatment facilities. Many
areas of Galveston County rely on on-site sewage facilities (septic systems) since they do not have access to
municipal sewer systems.
Galveston County is served by a variety of communications systems. In addition to land line, cellular, and
broadband communications systems, Galveston County has an extensive radio communications network that is
utilized by emergency services agencies, hospitals, law enforcement, public works, transportation, and other
supporting organizations.
The most common sources of potable water within Galveston County are municipal and private sources.
According to the Texas Commission on Environmental Quality Water Well Report Viewer, Galveston County
has 175 plotted and non-plotted water well reports. Municipal water supplies are provided by municipal utility
districts.
Extent
The extent and severity of a power outage depends on the cause, location, duration, and time of year. It can range
from a small, localized event to a countywide power outage. Impacts from an outage can be significant to the
county and its residents.
Power failures often result from damage to or electrical hazards within an electric power system. System
components include power generation plants, substations, circuits, switches, transformers, power lines, and
Section 4.3.16: Utility Failure
Galveston County, TX | Hazard Mitigation Plan 4-159
2022 Update
power poles. Due to the varied nature of power outage causes ranging from vehicle accidents to severe weather,
utility interruptions can happen at any time.
Power failures lead to the inability to use electric-powered equipment, such as: lighting; heating, ventilation, and
air conditioning (HVAC) and necessary equipment; communication equipment (telephones, computers, etc.);
fire and security systems; small appliances such as refrigerators, sterilizers, etc.; and medical equipment. This
all can lead to food spoilage, loss of heating and cooling, basement flooding due to sump pump failure, and loss
of water due to well pump failure.
Worst-Case Scenario
A wide-spread utility failure could impact the entire population of Galveston County. The vulnerable
populations (over 65 and under 5, below poverty threshold) and those who rely on power for home medical
devices would be more susceptible to utility failures. Another event like the snow/cold event of February 2021
would present a worst-case scenario with power outages lasting multiple days combined with temperatures
dropping to near-freezing levels.
Previous Occurrences
Many sources provided power outage information regarding previous occurrences and losses associated with
events that caused outages throughout Galveston County. With so many sources reviewed for the purpose of this
HMP, loss and impact information for many events could vary depending on the source. Therefore, the accuracy
of monetary figures discussed is based only on the available information identified during research for this HMP.
Between 1954 and 2021, FEMA included the State of Texas in one disaster declaration (DR) that included
widespread power outages.
For this plan update, power outage events were summarized from 2013 to 2021. Table 4-87 includes power
outage events that occurred between 2013 and 2020. With documentation for Texas and Galveston County being
so extensive, not all sources have been identified or researched. Therefore, Table 4-87 may not include all events
that have occurred throughout the County.
Table 4-87 Power Failure Events in Galveston County, 2013 to 2021
Date(s)
of Event Event Type
FEMA
Declaration
Number
(if
applicable)
County
Designated? Event Details*
May 27,
2014
Thunderstorm
Wind
N/A N/A Severe thunderstorm winds blew down a utility pole and power lines in
Galveston. Power poles were snapped at Crenshaw Elementary School.
February
14, 2017
Thunderstorm
Wind
N/A N/A Six power poles were blown down near the intersection of Highway 87
and Helen Blvd.
March 29,
2018
Thunderstorm
Wind
N/A N/A A power pole was downed near an apartment complex on 21st Street.
May 9,
2019
Thunderstorm
Wind
N/A N/A Trees and power lines downed along Highway 96 just west of Highway 3.
June 29,
2019
Thunderstorm
Wind
N/A N/A A large area of the Bolivar Peninsula was without power after strong
thunderstorm wind gusts were observed.
February
15-16,
2021
Cold/Wind
Chill
DR-4586 Yes Very cold air and gusty winds overspread SE Texas behind an Arctic
front with wind chill indices from near zero to single digits for much the
period from Sunday night to Tuesday morning. Increased power demand,
wind and ice led to widespread power outages. Bursting pipes caused
many to be without water as well.
September
13, 2021
Tropical
Storm
N/A N/A Hurricane Nicholas produced several hours of strong tropical storm force
sustained winds and gusts. There were numerous power outages and
minor to moderate damage to some structures and roofs. The storm also
produced minor storm surge flooding.
Section 4.3.16: Utility Failure
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2022 Update
Sources: National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Information (NCEI) 2021; FEMA
2021 FEMA Federal Emergency Management Agency
K Thousand ($)
N/A Not applicable
Climate Change Projections
The climate of Texas is changing. Most of the State has warmed between one half and one degree Fahrenheit in
the past century. Storms are more intense, and floods are becoming more severe. In the coming decades, storms,
including those causing utility failures, are likely to become more severe in Texas (EPA 2016).
Probability of Future Occurrences
While the probability of future power failure incidents in Galveston County is difficult to predict, historical
records indicate that significant power failures have occurred as a result of high winds and winter weather. Data
were not readily available on the frequency of smaller power outages across the county; however, it is reasonable
to assume that power failure events of shorter duration will continue to occur in the future. In addition, future
changes in climate may also impact the frequency and probability of future power failure occurrences.
Table 4-88 summarizes data regarding the probability of occurrences of utility failure events in Galveston
County based on the historic record. The information used to calculate the probability of occurrences is based
on the NOAA-NCEI Storm Events Database and FEMA.
Table 4-88. Probability of Future Occurrence of Utility Failure Events
Hazard Type
Number of Occurrences Between 1996
and 2021
% chance of occurrence in any
given year
Utility Failure 34 100%
Source: NOAA-NCEI 2021; FEMA 2021
Note: Disaster occurrences include federally declared disasters since the 1950 Federal Disaster Relief Act, and selected utility failure
events since 1968. Due to limitations in data, not all utility failure events occurring between 1954 and 1996 are accounted for in the
tally of occurrences. As a result, the number of hazard occurrences is underestimated.
Galveston County is expected to continue experiencing the direct and indirect impacts of utility failures. Thirty-
four recorded utility failure events in twenty-five years were recorded in Galveston County, giving the County
a 100% chance of being impacted by a utility failure in any given year. Based on historical records and input
from the Steering Committee, the probability of occurrence for utility failure events in the County is considered
frequent (100% chance occurring; occurs multiple times a year). Refer to Section 4.4 for additional information
on the hazard ranking methodology and probability criteria.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the utility failure hazard; therefore, all assets within
the County (population, structures, critical facilities, and lifelines), as described in Section 3 (County Profile),
are potentially vulnerable to a utility failure event. The following text evaluates and estimates the potential
impact of the utility failure hazard in the County.
Impact on Life, Health and Safety
The entire population of Galveston County is exposed to impacts from utility failures. However, vulnerable
populations, including the elderly, low income, and people with life -threatening illnesses are more susceptible
to negative impacts from utility failures. Power outages can be life threatening to those dependent on electricity
for life support. The population over the age of 65 (46,103) are most likely to rely on electricity for life support.
Section 4.3.16: Utility Failure
Galveston County, TX | Hazard Mitigation Plan 4-161
2022 Update
Power outages can be especially harmful to life, health, and safety, during winter and summer months, when
people rely on electricity to mitigate the harmful effects of extreme temperatures such as frostbite, hypothermia,
heat exhaustion, and heat stroke. Power outages can also contribute to traffic accidents when streetlights and
traffic signals are inoperable.
Power outages can also impact residents’ access to water, as domestic wells require power to operate. Domestic
wells are relatively common in Galveston County, with about 20-30 wells per square kilometer (USGS 2019).
This can further exacerbate the impacts on health of extreme temperature events, where drinking water is
essential in preventing heat exhaustion and heat stroke.
Impact on General Building Stock
All of the building stock in the County is exposed to the utility failure hazard. Refer to Section 3 (County Profile)
which summarizes the building inventory in Galveston County. Impacts sustained from utility interruption are
likely to be secondary impacts. Should potable water distribution be reduced or not available, then structures
could be at increased risk for structural fire since current fire suppression is dependent accessing water supply
from hydrants. Utility failure does not impact directly impact buildings, but it does impact business function.
Utility failure can indirectly impact the building stock when coupled with extreme temperature events, leading
to problems such as frozen and burst pipes.
Impact on Critical Facilities
All critical facilities in the County are exposed to the utility failure hazard. It is essential that critical facilities
remain operational during natural hazard events, as many people rely on them to mitigate the effects of hazard
events. Loss of power can have serious impacts on the health and welfare of residents, continuity of business,
and the ability of public safety agencies to respond to emergencies. Interruption of utility gas or water distribution
could also reduce the effectiveness of critical facilities to operate at full capacity. Backup power is recommended
for critical facilities and infrastructure.
Impact on the Economy
During a utility interruption event, the County may experience losses because of an interruption of critical
services. Further, increased costs such as providing shelters, and costs related to cooling and heating centers may
be incurred. Extended power outages will require officials to shelter victims who require heat and power for
activities of daily living.
A prolonged power failure in Galveston County may impact the County’s economy. With major roadways,
businesses, and tourist destinations, any disruption would mean that many workers, residents, and travelers
would not be able to go where needed.
Power interruptions can cause economic impacts stemming from lost income, spoiled food and other goods,
costs to the owners/operators of the utility facilities, and costs to government and community service groups.
FEMA’s benefit-cost analysis methodology measures the loss of electrical service on a per-person-per-day-of-
lost-service basis for the service area affected.
Interruption of utility gas or potable water distribution could also cause significant economic impacts such as:
additional costs for bringing in water tenders to maintain fire suppression capabilities; opening additional
warming centers should electric and gas utility be interrupted to residential areas; and distribution of potable
water for public consumption. There could be significant costs associated with reimbursing fire departments
from other counties within Texas to travel, staff, and maintain water tenders within Galveston County during the
duration of a water outage event.
Section 4.3.16: Utility Failure
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2022 Update
Potential modeling of economic impacts from utility interruption would be calculating interruption of service
costs which is derived from a standard value per person per day multiplied out by the number of customers
served. This would help to provide an estimate of the impact of the interrupted utility service but may not be
representative of the complete economic impact of a prolonged utility interruption. The FEMA BCA Toolkit
version 5.3 uses the following standard values per person per day:
• Electric - $148.00
• Potable water - $105.00
• Wastewater - $49.00
Impact on the Environment
Utility failure is not known to directly impact the environment. However, secondary impacts may occur when
power is lost at sewage pump stations and treatment plants. Overflows can occur which contaminate the local
environment and groundwater supply. When power failures occur at mechanized flood control infrastructure,
the likelihood of flood damage to the natural environment increases, including streambed scour and topsoil
erosion.
Future Changes that May Impact Vulnerability
Understanding future changes that effect vulnerability in the County can assist in planning for future
development and ensure establishment of appropriate mitigation, planning, and preparedness measures. The
County considered the following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development.
• Projected changes in population.
• Other identified conditions as relevant and appropriate, including the impacts of climate change.
Projected Development
Understanding future changes that impact vulnerability in the County can assist in planning for future
development and ensuring that appropriate mitigation, planning, and preparedness measures are in place. With
more development, more buildings and people will be exposed to the utility failure hazard.
Projected Changes in Population
The County experienced an increase in population between the 2010 Census (291,309) and the estimated 2015-
2019 American Community Survey estimated population of 350,682. The population of the County is expected
to increase over the next few years. The increase in population will expose more people to the utility failure
hazard.
Climate Change
Due to climate change, storms such as hurricanes, and thunderstorms are becoming more intense (EPA 2016).
Therefore, the frequency and intensity of utility failures will most likely increase. Furthermore, increasing
temperatures and frequencies of droughts are likely to exacerbate the effects of utility failures. Lastly, as
temperatures rise and energy demands thus also increase, increasing the likelihood of utility failure due to brown-
outs.
Change of Vulnerability Since the 2017 HMP
Utility failure was not included as a hazard in the 2017 HMP. However, it was discussed in the vulnerability
assessments of natural events that cause utility failures. For the 2022 Update, the Planning Partnership agreed to
have a standalone profile focusing on utility failures in the County.
Section 4.3.17: Wildfire
Galveston County, TX | Hazard Mitigation Plan 4-163
2022 Update
4.3.17 Wildfire
The following section provides the hazard profile and vulnerability assessment for the wildfire hazard for
Galveston County.
Profile
Hazard Description
Wildland fire is defined as any fire burning wildland vegetation‐fuels; it includes prescribed fire, wildland fire
use, and wildfire. Prescribed fires are planned fires started by land managers to accomplish specific natural
resource objectives. Fires that occur from natural causes, such as lightning, that are then used to achieve
management purposes under carefully controlled conditions with minimal suppression costs are known as
wildland fire use (WFU).
Wildfires are unwanted and unplanned fires that result from natural ignition, unauthorized human-caused fire,
escaped WFU, or escaped prescribed fire.
A wildland‐urban interface (WUI) fire is a wildfire occurring in the wildland urban interface. The WUI is
described as the area where structures and other human improvements meet and intermingle with undeveloped
wildland or vegetative fuels. Population growth within the WUI substantially increases the risk from wildfire.
Prescribed burning, also known as controlled burning, is the deliberate use of fire under specified and controlled
conditions. Prescribed burning is used by forest management professionals and individual landowners to
accomplish one or more of the following tasks:
• Fuel Reduction – The reduction of accumulated grass, weeds, pine needles, and hardwood leaves. This
type of vegetation can encourage wildfires in young stands and hinder regeneration of older stands.
• Hardwood Control – Prevents hardwood trees from competing with pines for nutrients and moisture;
impeding visibility and access through the stands; and interfering with natural regeneration in areas
better suited for growing pines.
The wildland interface problem has grown due to increases in population, urban expansion, land management
decisions, parks, greenbelts and the ever‐present desire to intermingle with nature (Galveston County 2017).
Location
Wildfires can be a potentially damaging outgrowth of drought. While they are not confined to any specific
geographic location, and can vary greatly in terms of size, location, intensity, and duration; they are most likely
to occur in open grasslands. The threat to people and property is greater in the fringe areas where developed
areas meet open grass lands. See Figure 4-47 for wildfire ignition locations in Galveston County. According to
Texas A&M Forest Service, none of those wildfires were considered “large”, which means none of them reached
500 acres. Figure 4-48 shows the extent of the WUI in Galveston County. There are small areas of the intermix
areas in the eastern and western portions of the County, with an area of interface and intermix in the La Marque-
Hitchcock CCD.
Section 4.3.17: Wildfire
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2022 Update
Figure 4-47 Wildfire Ignition Locations 2005-2020
Source: (Texas A&M Forest Service 2021)
Section 4.3.17: Wildfire
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2022 Update
Figure 4-48 WUI in Galveston County
Section 4.3.17: Wildfire
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2022 Update
Extent
Fire risk is measured in terms of magnitude and intensity using the Keetch-Byram Drought Index (KBDI), a
mathematical system for relating current and recent weather conditions to potential or expected fire behavior.
The KBDI determines forest fire potential based on a daily water balance, where a drought factor is balanced
with precipitation and soil moisture (assumed to have a maximum storage capacity of 8 inches) and is expressed
in hundredths of an inch of soil moisture depletion.
Each color on the map represents the drought index at that location. The index ranges from zero, the point of no
moisture deficiency, to 800, the maximum drought that is possible (NOAA NIDIS n.d.).
Figure 4-49 Keetch-Byram Drought Index for the State of Texas, December 6, 2021
Source: (Texas Weather Connection 2021)
Note: The black circle denotes the approximate location of Galveston County.
Fire behavior can be categorized at four distinct levels:
• 0-200 – Soil and fuel moisture are high. Most fuels will not readily ignite or burn. However, with
sufficient sunlight and wind, cured grasses and some light surface fuels will burn in spots and patches.
Section 4.3.17: Wildfire
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2022 Update
• 200-400 – Fires more readily burn and will carry across an area with no gaps. Heavier fuels will still
not readily ignite and burn. Expect smoldering and the resulting smoke to carry into and possibly
through the night.
• 400-600 – Fire intensity begins to significantly increase. Fires will readily burn in all directions exposing
mineral soils in some locations. Larger fuels may burn or smolder for several days creating possible
smoke and control problems.
• 600-800 – Fires will burn to mineral soil. Stumps will burn to the end of underground roots and spotting
will be a major problem. Fires will burn through the night and heavier fuels will actively burn and
contribute to fire intensity.
Using the KBDI index is a good measure of the readiness of fuels for wildland fire. Caution should be exercised
in dryer, hotter conditions, and the KBDI should be referenced as the area experiences changes in precipitation
and soil moisture.
Worst-Case Scenario
A worst-case scenario would involve a wildfire during a high wind event, preceded by prolonged elevated
temperatures and drought, however since insufficient historical records exist, it is not possible to use previous
records to project specific damages for a worst-case scenario in the future. Nevertheless, this type of event would
have both a short- and long-term effects on the planning area. The fire could burn structures and infrastructure
creating power and communication outages. Parts of the planning area could experience limited ingress and
egress as transportation corridors are blocked by fire. Air quality would be affected and could pose serious risks
for the elderly and those with compromised respiratory systems.
Previous Occurrences
Between 1988 and 2021, Texas had 250 FEMA disaster declarations for wildfire, however Galveston County
was not included in any of those declarations. Likewise, between 1950 and 2021, the NCEI Storm Events
Database did not include any wildfire events for Galveston County. For this HMP update, there was limited
information regarding wildfire events in the planning area.
Climate Change Projections
Climate change has the potential to affect multiple elements of the wildfire system: fire behavior, ignitions, fire
management, and vegetation fuels. Hot dry spells create the highest fire risk. Increased temperatures may
intensify wildfire danger by warming and drying out vegetation.
Changes in climate patterns may impact the distribution and perseverance of insect outbreaks that create dead
trees (increase fuel). When climate alters fuel loads and fuel moisture, forest susceptibility to wildfires changes.
Climate change also may increase winds that spread fires. Faster fires are harder to contain, and thus are more
likely to expand into residential neighborhoods.
Probability of Future Occurrences
Due to the lack of data on past wildfire events in the planning area, the probability of future events is based on
event history and input from the Steering Committee. The probability of occurrence for wildfire events in the
planning area is considered occasional (between 10 and 100% annual chance of occurring.
Vulnerability Assessment
To understand risk, a community must evaluate assets exposed to and vulnerable to the identified hazard. The
entirety of Galveston County is exposed and vulnerable to the wildfire hazard; therefore, all assets within the
County (population, structures, critical facilities, and lifelines), as described in Section 3 (County Profile), are
Section 4.3.17: Wildfire
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2022 Update
potentially vulnerable to a wildfire event. The following text evaluates and estimates the potential impact of the
wildfire hazard in the County.
Impact on Life, Health and Safety
All people exposed to the wildfire hazard are potentially vulnerable to wildfire impacts. Smoke and air pollution
from wildfires can be a severe health hazard, especially for sensitive populations, including children, the elderly
and those with respiratory and cardiovascular diseases. In addition, wildfire may threaten the health and safety
of those fighting the fires. First responders are exposed to dangers from the initial incident and after-effects from
smoke inhalation and heat stroke. Persons with access and functional needs, the elderly and very young may be
especially vulnerable to a wildfire if there is not adequate warning time before evacuation is needed. However,
due to the humid climate of the Galveston County planning area, the number of previous occurrences and the
potential property at risk, the impact of an event would be minor with few injuries. Furthermore, there is only a
small percentage (1%) of Galveston County’s population that is located within the wildfire hazard area (Table
4-89).
Table 4-89. Estimated Population Located Within the WUI
Source: University of Wisconsin 2010, American Community Survey 2019 (5-year estimates 2015-2019)
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on General Building Stock
All property exposed to the wildfire hazard is vulnerable. Structures that were not constructed to standards
designed to protect a building from a wildfire may be especially vulnerable. As of 2008, the International
Building code requires minimum standards be met for new buildings in fire hazard severity zones. It is unknown
how many buildings in the County were built to these standards. However, there is only a small percentage of
buildings in the County that are located in the Wildland-Urban Interface/Intermix wildfire fuel hazard area, thus
not many are vulnerable to wildfires (Table 4-90 and Table 4-91).
Jurisdiction
Total
Population
(American
Community
Survey 2015-
2019)
Estimated Population Located Within the Wildland-Urban
Interface/Intermix (WUI) Wildfire Hazard Areas
Number of
People in the
WUI Interface
Wildfire
Hazard Area Percent of Total
Number of
People in the
WUI Intermix
Wildfire Hazard
Area Percent of Total
Bayou Vista (C) 1,763 0 0.0% 0 0.0%
Clear Lake Shores (C) 1,258 0 0.0% 0 0.0%
Dickinson (C) 20,847 0 0.0% 0 0.0%
Friendswood (C) 41,213 0 0.0% 0 0.0%
Hitchcock (C) 7,301 0 0.0% 0 0.0%
Jamaica Beach (C) 1,078 0 0.0% 0 0.0%
Kemah (C) 1,807 0 0.0% 0 0.0%
La Marque (C) 18,030 0 0.0% 0 0.0%
League City (C) 114,392 0 0.0% 0 0.0%
Santa Fe (C) 12,735 0 0.0% 0 0.0%
Tiki Island (V) 1,106 0 0.0% 0 0.0%
Galveston County (Total) 350,682 1,254 0.4% 1,973 0.6%
Section 4.3.17: Wildfire
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2022 Update
Table 4-90. Building Stock Located within the Wildland-Urban Interface Wildfire Hazard Area
Jurisdiction
Total
Number of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located Within the
Wildland-Urban Interface (WUI) Wildfire Fuel
Hazard Areas
Number
of
Buildings
in the
WUI
Hazard
Area
Percent
of Total
Total
Replacement
Cost Value of
Buildings
Located in
the WUI
Hazard Area
Percent
of Total
Bayou Vista (C) 1365 $445,354,087.33 0 0.0% $0 0.0%
Clear Lake Shores (C) 1155 $904,562,368.66 0 0.0% $0 0.0%
Dickinson (C) 10351 $6,601,710,645.63 0 0.0% $0 0.0%
Friendswood (C) 14891 $10,815,456,384.12 0 0.0% $0 0.0%
Hitchcock (C) 5452 $4,592,036,651.86 0 0.0% $0 0.0%
Jamaica Beach (C) 1291 $458,205,838.82 0 0.0% $0 0.0%
Kemah (C) 1634 $2,631,702,105.60 0 0.0% $0 0.0%
La Marque (C) 10749 $7,927,292,522.28 0 0.0% $0 0.0%
League City (C) 46742 $31,237,974,594.10 0 0.0% $0 0.0%
Santa Fe (C) 7942 $4,831,628,162.13 0 0.0% $0 0.0%
Tiki Island (V) 868 $365,209,145.44 0 0.0% $0 0.0%
Galveston County (Total) 209947 $166,321,604,688.46 1,173 0.6% $599,635,507 0.4%
Source: University of Wisconsin 2010, Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Table 4-91. Building Stock Located within the Wildland-Urban Intermix Wildfire Hazard Area
Jurisdiction
Total
Number
of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located Within the
Wildland-Urban Intermix (WUI) Wildfire Fuel
Hazard Areas
Number
of
Buildings
in the
WUI
Hazard
Area
Percent
of Total
Total
Replacement
Cost Value of
Buildings
Located in the
WUI Hazard
Area
Percent
of Total
Bayou Vista (C) 1365 $445,354,087.33 0 0.0% $0 0.0%
Clear Lake Shores (C) 1155 $904,562,368.66 0 0.0% $0 0.0%
Dickinson (C) 10351 $6,601,710,645.63 0 0.0% $0 0.0%
Friendswood (C) 14891 $10,815,456,384.12 0 0.0% $0 0.0%
Hitchcock (C) 5452 $4,592,036,651.86 0 0.0% $0 0.0%
Jamaica Beach (C) 1291 $458,205,838.82 0 0.0% $0 0.0%
Kemah (C) 1634 $2,631,702,105.60 0 0.0% $0 0.0%
La Marque (C) 10749 $7,927,292,522.28 0 0.0% $0 0.0%
League City (C) 46742 $31,237,974,594.10 0 0.0% $0 0.0%
Santa Fe (C) 7942 $4,831,628,162.13 0 0.0% $0 0.0%
Tiki Island (V) 868 $365,209,145.44 0 0.0% $0 0.0%
Section 4.3.17: Wildfire
Galveston County, TX | Hazard Mitigation Plan 4-170
2022 Update
Jurisdiction
Total
Number
of
Buildings
Total Replacement
Cost Value (RCV)
Estimated Building Stock Located Within the
Wildland-Urban Intermix (WUI) Wildfire Fuel
Hazard Areas
Number
of
Buildings
in the
WUI
Hazard
Area
Percent
of Total
Total
Replacement
Cost Value of
Buildings
Located in the
WUI Hazard
Area
Percent
of Total
Galveston County (Total) 209947 $166,321,604,688.46 1,812 0.9% $1,138,026,689 0.7%
Source: University of Wisconsin 2010, Galveston Central Appraisal District; Microsoft Bing 2018; RS Means 2021
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on Critical Facilities
Critical facilities not built to fire protection standards. Utility poles and lines, and facilities containing hazardous
materials are most vulnerable to the wildfire hazard. Most roads and railroads would not sustain damage except
in the worst scenarios, although roads and bridges can be blocked by debris or other wildfire -related conditions
and become impassable. While Table 4-92 indicates that no critical facilities are located in the wildland-urban
interface (WUI) wildfire hazard area, if a wildfire reached the following critical facilities, their vulnerability
could complicate response and recovery efforts during and following an event:
• Hazardous Materials and Fuel Storage—During a wildfire event, these materials could rupture due
to excessive heat and act as fuel for the fire, causing rapid spreading and escalating the fire to
unmanageable levels. In addition, they could leak into surrounding areas, saturating soils, and seeping
into surface waters, and have a disastrous effect on the environment.
• Communication Facilities—If these facilities are damaged and become inoperable, it would exacerbate
already difficult communication in the planning area.
• Fire Stations—If fire stations were compromised during a wildfire event, it would make fire
suppression and support services even more challenging.
Table 4-92. Estimated Critical Facilitates and Lifelines Located within the Wildland-Urban Interface
Wildfire Hazard Area
Jurisdiction
Total Critical
Facilities
Located in
Jurisdiction
Total
Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline Facilities
Located in the Wildland-Urban Interface Wildfire
Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent
of Total
Lifelines
Bayou Vista (C) 5 5 0 0.0% 0 0.0%
Clear Lake Shores (C) 24 24 0 0.0% 0 0.0%
Dickinson (C) 91 83 0 0.0% 0 0.0%
Friendswood (C) 96 82 0 0.0% 0 0.0%
Hitchcock (C) 214 212 0 0.0% 0 0.0%
Jamaica Beach (C) 11 11 0 0.0% 0 0.0%
Kemah (C) 15 14 0 0.0% 0 0.0%
La Marque (C) 121 107 0 0.0% 0 0.0%
League City (C) 321 283 0 0.0% 0 0.0%
Section 4.3.17: Wildfire
Galveston County, TX | Hazard Mitigation Plan 4-171
2022 Update
Jurisdiction
Total Critical
Facilities
Located in
Jurisdiction
Total
Lifelines
Located in
Jurisdiction
Number of Critical Facilities and Lifeline Facilities
Located in the Wildland-Urban Interface Wildfire
Hazard Area
Critical
Facilities
Percent of
Total Critical
Facilities Lifelines
Percent
of Total
Lifelines
Santa Fe (C) 135 128 0 0.0% 0 0.0%
Tiki Island (V) 7 7 0 0.0% 0 0.0%
Galveston County (Total) 2,437 2,317 0 0.0% 0 0.0%
Sources: Essential Government Functions Government Offices 2021; City of Galveston 2021; HIFLD 2020; Texas Commission on
Environmental Quality 2021; Texas Tech University 2021; University of Wisconsin 2010
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on the Economy
Wildfire events can have major economic impacts on a community from the initial loss of structures and the
subsequent loss of revenue from destroyed business and decrease in tourism. Wildfires can cost thousands of
taxpayer dollars to suppress and control and can involve hundreds of operating hours on fire apparatus and
thousands of volunteer man hours from the volunteer firefighters. There are also many direct and indirect costs
to local businesses that excuse volunteers from working to fight these fires.
Table 4-93. Estimated Building Stock Located Within the WUI
Jurisdiction
Estimated Building Stock Located Within the Wildland-Urban Interface/Intermix (WUI) Wildfire Fuel
Hazard Areas
Number
of
Buildings
in the
WUI
Interface
Wildfire
Hazard
Area
Percent
of Total
Total
Replacement
Cost Value of
Buildings
Located in
the WUI
Interface
Wildfire
Hazard Area
Percent
of Total
Number
of
Buildings
in the
WUI
Intermix
Wildfire
Hazard
Area
Percent
of Total
Total
Replacement
Cost Value of
Buildings
Located in the
WUI Intermix
Wildfire
Hazard Area
Percent
of Total
Bayou Vista (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Clear Lake Shores (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Dickinson (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Friendswood (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Hitchcock (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Jamaica Beach (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Kemah (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
La Marque (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
League City (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Santa Fe (C) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Tiki Island (V) 0 0.0% $0 0.0% 0 0.0% $0 0.0%
Galveston County (Total) 1,173 0.6% $599,635,507 0.4% 1,812 0.9% $1,138,026,689 0.7%
Sources: Essential Government Functions Government Offices 2021; City of Galveston 2021; HIFLD 2020; Texas Commission on
Environmental Quality 2021; Texas Tech University 2021; University of Wisconsin 2010
Note: The County total includes non-participating jurisdictions, census county divisions, and unincorporated areas in the County.
Impact on the Environment
Fire is a natural and critical ecosystem process in most terrestrial ecosystems, affecting the types, structure, and
spatial extent of native vegetation. However, it also can cause severe environmental impacts:
• Damaged Fisheries—Critical fisheries can suffer from increased water temperatures, sedimentation,
and changes in water quality.
Section 4.3.17: Wildfire
Galveston County, TX | Hazard Mitigation Plan 4-172
2022 Update
• Soil Erosion—The protective covering provided by foliage and dead organic matter is removed, leaving
the soil fully exposed to wind and water erosion. Accelerated soil erosion occurs, causing landslides
and threatening aquatic habitats.
• Spread of Invasive Plant Species—Non-native woody plant species frequently invade burned areas.
When weeds become established, they can dominate the plant cover over broad landscapes, and become
difficult and costly to control.
• Disease and Insect Infestations—Unless diseased or insect-infested trees are swiftly removed,
infestations and disease can spread to healthy forests and private lands. Timely active management
actions are needed to remove diseased or infested trees.
• Destroyed Endangered Species Habitat—Fire can have negative consequences for endangered
species.
• Soil Sterilization—Some fires burn so hot that they can sterilize the soil. Topsoil exposed to extreme
heat can become water repellant, and soil nutrients may be lost.
• Reduced Timber Harvesting—Timber can be destroyed and lead to smaller available timber harvests.
• Reduced Agricultural Resources—Wildfire can have disastrous consequences on agricultural
resources, removing them from production and necessitating lengthy restoration programs.
• Damaged Cultural Resources—Scenic vistas can be damaged, access to recreational areas can be
reduced and destruction of cultural resources may occur.
Future Changes that May Impact Vulnerability
Understanding future changes that affect vulnerability can assist in planning for future development and ensure
establishment of appropriate mitigation, planning, and preparedness measures. The County considered the
following factors to examine potential conditions that may affect hazard vulnerability:
• Potential or projected development
• Projected changes in population
• Other identified conditions as relevant and appropriate, including the impacts of climate change
Projected Development
As a highly urbanized planning area, wildfire risk exposure is low. Urbanization tends to alter the natural fire
regime and can create the potential for the expansion of urbanized areas into wildland areas. The expansion of
development toward wildfire hazard areas can be managed with strong land use and building codes. The
International Building Code includes minimum standards related to the design and construction of buildings in
fire hazard zones. The planning area is well equipped with these tools and this planning process has assessed
capabilities with regards to the tools. As the planning area experiences future growth, it is anticipated that the
exposure to this hazard will remain as assessed or even decrease over time due to these capabilities.
Projected Changes in Population
The County experienced an increase in population between the 2010 Census (291,309) and the estimated 2015-
2019 American Community Survey estimated population of 350,682. The population of the County is expected
to increase over the next few years. The increase in population will expose more people to the wildfire hazard.
Climate Change
Climate change has the potential to affect multiple elements of the wildfire system: fire behavior, ignitions, fire
management, and vegetation fuels. Hot dry spells create the highest fire risk. Increased temperatures may
intensify wildfire danger by warming and drying out vegetation. Changes in climate patterns may impact the
distribution and perseverance of insect outbreaks that create dead trees (increase fuel). When climate alters fuel
Section 4.4.1: Hazard Ranking Methodology
Galveston County, TX | Hazard Mitigation Plan 4-173
2022 Update
loads and fuel moisture, forest susceptibility to wildfires changes. Climate change also may increase winds that
spread fires. Faster fires are harder to contain, and thus are more likely to expand into residential neighborhoods.
Change of Vulnerability Since the 2017 HMP
For this hazard mitigation plan update, the 2010 Wildland-Urban Interface/Intermix data from the University of
Wisconsin was referenced to determine areas within Galveston County that are vulnerable to wildfires.
Population statistics have also been updated using the 5-Year 2015-2019 American Community Survey
Population Estimates. The 2017 general building stock was updated using RS Means 2021 replacement cost
values and updated parcel and tax assessment information from the Galveston Central Appraisal District.
Additionally, the critical facility inventory was updated by Galveston County.
Overall, this vulnerability assessment uses a more accurate and updated building inventory which provides more
accurate estimated exposure and potential losses for Galveston County.
4.4 RISK RANKING
A comprehensive range of hazards that pose a significant risk to Galveston County were selected and considered
during the development of this plan; see Section 4.2 (Identification of Hazards of Concern). However, each
community has differing levels of exposure and vulnerability to each of these hazards. It is important for each
community participating in this plan to recognize those hazards that pose the greatest risk to their community
and direct their attention and resources accordingly to manage risk and reduce losses most effectively and
efficiently. The hazard ranking for the County and each participating jurisdiction can be found in their
jurisdictional annexes in Volume II, Section 9 (Jurisdictional Annexes) of this plan.
To this end, a hazard risk ranking process was conducted for Galveston County and its jurisdictions using the
method described below. This method includes four risk assessment categories—probability of occurrence,
impact (population, property, and economy), adaptive capacity, and changing future conditions (i.e., climate
change). Each was assigned a weighting factor to calculate an overall ranking value for each hazard of concern.
Depending on the calculation, each hazard was assigned a high, medium, or low ranking. Details regarding each
of these categories is described below.
4.4.1 Hazard Ranking Methodology
Estimates of hazard risk for the County were developed using methodologies promoted by FEMA’s hazard
mitigation planning guidance, generated by FEMA’s Hazus risk assessment tool, and input from Galveston
County and participating jurisdictions.
As described in Section 4.1 (Methodology and Tools), three different levels of analysis were used to estimate
potential impacts: 1) historic loss/qualitative analysis; 2) exposure analysis; and 3) loss estimation. All three
levels of analysis are suitable for planning purposes; however, with any risk analysis, there is underlying
uncertainty resulting from assumptions used to describe and assess vulnerability and the methodologies available
to model impacts. Impacts from any hazard event within the County will vary from the analysis presented here
based on the factors described for each hazard of concern, namely location, extent, warning time, and mitigation
measures in place at the time of an event.
The hazard ranking methodology for some hazards of concern is based on a scenario event, while others are
based on their potential risk to the County as a whole. In order to account for these differences, the quantitative
hazard ranking methodology was adjusted using professional judgement and subject-matter input; assumptions
are included, as appropriate, in the following subsections. The limitations of this analysis are recognized given
the scenarios do not have the same likelihood of occurrence; nonetheless, there is value in summarizing and
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-174
2022 Update
comparing the hazards using a standardized approach to evaluate relative risk. The following categories were
considered when evaluating the relative risk of the hazards of concern.
• Probability of Occurrence - The probability of occurrence of the scenario evaluated was estimated by
examining the historic record and/or calculating the likelihood of annual occurrence. When no scenario
was assessed, an examination of the historic record and judgement was used to estimate the probability
of occurrence of an event that will impact the County.
• Impact—The following three hazard impact subcategories were considered: impact to people; impact
to buildings; and impact to the economy. The results of the updated risk assessment and/or professional
judgement were used to assign the numeric values for these three impact subcategories. A factor was
applied to each subcategory, giving impact on population the greatest weight.
o Population—Numeric value x 3
o Buildings—Numeric value x 2
o Economy—Numeric value x 1
• Adaptive Capacity - Adaptive capacity describes a jurisdiction’s current ability to protect from or
withstand a hazard event. This includes capabilities and capacity in the following areas: administrative,
technical, planning/regulatory, and financial. Mitigation measures already in place increases a
jurisdiction’s capacity to withstand and rebound from events (e.g. codes/ordinances with higher
standards to withstand hazards due to design or location; deployable resources; or plans and procedures
in place to respond to an event). In other words, assigning ‘weak’ for adaptive capacity means the
jurisdiction does not have the capability to effectively respond, which increases vulnerability; whereas
‘strong’ adaptive capacity means the jurisdiction does have the capability to effectively respond, which
decreases vulnerability. These ratings were assigned using the results of the core capability assessment
with subject-matter input from each jurisdiction.
• Climate Change (Changing Future Conditions) - Current climate change projections were considered
as part of the hazard ranking to ensure the potential for an increase in severity/frequency of the hazard
was included. This was important to Galveston County to include because the hazard ranking helps
guide and prioritize the mitigation strategy development, which should have a long-term future vision
to mitigate the hazards of concern. The potential impacts climate change may have on each hazard of
concern is discussed in Sections 4.3.1 through 4.3.17. The benchmark values in the methodology are
similar to confidence levels outlined in the National Climate Assessment 2017.
Table 4-94summarizes the categories, benchmark values, and weights used to calculate the risk factor for each
hazard. Using the weighting applied, the highest possible risk factor value is 6.9. The higher the number, the
greater the relative risk. Based on the total for each hazard, a priority ranking is assigned to each hazard of
concern (high, medium, or low). The rankings were categorized as follows: Low = Values less than 3.9; Medium
= Values between 3.9 and 4.9; High = Values greater than 4.9.
Table 4-94. Summary of Hazard Ranking Approach
Category
Level /
Category Degree of Risk / Benchmark Value
Numeric
Value
Weighted
Value
Probability of
Occurrence
Unlikely A hazard event is not likely to occur or is unlikely to occur
with less than a 1% annual chance probability.
0 30%
Hazard Ranking Equation
[Probability of Occurrence x 0.3] + [(Impact on Population x 3) + (Impact on Property x 2) + (Impact on
Economy x 1) x 0.3] + [Adaptive Capacity x 0.3] + [Climate Change x 0.1]
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-175
2022 Update
Category
Level /
Category Degree of Risk / Benchmark Value
Numeric
Value
Weighted
Value
Rare Between 1 and 10% annual probability of a hazard event
occurring.
1
Occasional Between 10 and 100% annual probability of a hazard event
occurring.
2
Frequent 100% annual probability; a hazard event may occur multiple
times per year.
3
Impact
(Sum of
all 3)
Population
(Numeric
Value x 3)
Low 14% or less of your population is exposed to a hazard with
potential for measurable life safety impact, due to its extent
and location.
1 30%
Medium 15% to 29% of your population is exposed to a hazard with
potential for measurable life safety impact, due to its extent
and location.
2
High 30% or more of your population is exposed to a hazard with
potential for measurable life safety impact, due to its extent
and location.
3
Property
(Numeric
Value x 2)
Low Property exposure is 14% or less of the total number of
structures for your community.
1
Medium Property exposure is 15% to 29% of the total number of
structures for your community.
2
High Property exposure is 30% or more of the total number of
structures for your community.
3
Economy
(Numeric
Value x 1)
Low Loss estimate is 9% or less of the total replacement cost for
your community.
1
Medium Loss estimate is 10% to 19% of the total replacement cost for
your community.
2
High Loss estimate is 20% or more of the total replacement cost for
your community.
3
Adaptive Capacity Weak Weak/outdated/inconsistent plans, policies, codes/ordinances
in place; no redundancies; limited to no deployable resources;
limited capabilities to respond; long recovery.
1 30%
Moderate Plans, policies, codes/ordinances in place and meet minimum
requirements; mitigation strategies identified but not
implemented on a widespread scale; county/jurisdiction can
recover but needs outside resources; moderate
county/Jurisdiction capabilities.
0
Strong Plans, policies, codes/ordinances in place and exceed
minimum requirements; mitigation/protective measures in
place; county/jurisdiction has ability to recover quickly
because resources are readily available, and capabilities are
high.
-1
Climate Change Low No local data is available; modeling projections are uncertain
on whether there is increased future risk; confidence level is
low (inconclusive evidence).
1 10%
Medium Studies and modeling projections indicate a potential for
exacerbated conditions due to climate change; confidence
level is medium to high (suggestive to moderate evidence).
2
High Studies and modeling projections indicate exacerbated
conditions/increased future risk due to climate change; very
high confidence level (strong evidence, well documented and
acceptable methods).
3
Note: A numerical value of zero is assigned if there is no impact.
*For the purposes of this exercise, “impacted” means exposed for population and property and estimated loss for economy.
For non-natural hazards, although they may occur anywhere in the County, an event will not likely cause countywide
impacts; therefore, impact to population was scored using an event-specific scenario.
In an attempt to summarize the confidence level regarding the input utilized to populate the hazard ranking, a
gradient of certainty was developed. A certainty factor of high, medium, or low was selected and assigned to
each hazard to provide a level of transparency and increased understanding of the data utilized to support the
resulting ranking. The following scale was used to assign a certainty factor to each hazard:
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-176
2022 Update
• High—Defined scenario/event to evaluate; probability calculated; evidenced-based/quantitative
assessment to estimate potential impacts through hazard modeling.
• Moderate—Defined scenario/event or only a hazard area to evaluate; estimated probability;
combination of quantitative (exposure analysis, no hazard modeling) and qualitative data to estimate
potential impacts.
• Low—Scenario or hazard area is undefined; there is a degree of uncertainty regarding event probability;
majority of potential impacts are qualitative.
Table 4-95 summarizes the hazard scenario or hazard area evaluated; highlights key impacts to population,
buildings/critical assets, and the economy; and lists the associated certainty factor assigned for each hazard to
convey the level of confidence in the data used. This table is n ot intended to be a complete and comprehensive
list of all hazard impacts determined in the risk assessment and considered for the hazard ranking exercise. Refer
to Sections 4.3.1 to 4.3.17 for a complete summary of all estimated impacts for each hazard.
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-177
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Table 4-95. Overview of the Hazard Scenario and Associated Estimated Impacts Considered in the Hazard Ranking
Hazard of
Concern
Hazard/ Scenario Area
Evaluated Population Buildings Economya
Certainty
Factor
Coastal and
Inland Erosion
Exposure to the Coastal
Erosion Hazard Area
Coastal Erosion Hazard
Area:
5,049 Coastal Erosion Hazard
Area:
4,922 Coastal Erosion Hazard Area: $6,077,155,937 Moderate
Exposure to Inland
Erosion Hazard Area
Inland Erosion Hazard
Area:
37,595 Inland Erosion Hazard
Area:
21,966 Inland Erosion Hazard Area: $16,543,834,687
Dam/ Levee
Failure
Partial or complete failure
of a dam or levee. There
are 2 dams and five levee
systems in the County.
Population impacted is dependent on the
location and capacity of the dam or
levee, the extent of the failure
inundation area and the severity of the
failure.
The number of buildings impacted is
dependent on the capacity of the
dam/levee, the extent of the
dam/levee failure inundation area,
and the severity of the failure.
Economic impacts include
dam/levee/building/infrastructure repairs; debris
removal/disposal; utility impacts.
Moderate
Drought Prolonged drought event -
the County is serviced
water suppliers who
primarily get water from
surface water, reservoirs,
and unconfined
groundwater sources.
Entire population exposed. Population
on surface water supplies may be
impacted first; water
restrictions/contamination; increased
wildfire risk.
Droughts are not expected to cause
direct damage to buildings.
Losses include aesthetic,
landscape/nursery/agricultural industry impacts
Moderate
Expansive Soils Soils (Linear Extensibility
>6%) Hazard Area
Soils (Linear Extensibility
>6%) Hazard Area:
167,514 Soils (Linear
Extensibility >6%)
Hazard Area:
85,766 Soils (Linear Extensibility
>6%) Hazard Area:
$62,998,467,572 Moderate
Extreme
Temperature
Extreme hot and cold
events
All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident.
Business and commercial losses due to long-term
utility outages; repairs to power and utility lines.
Moderate
Flood 1% annual chance
(100-year) and 0.2%
annual chance (500-year)
1% annual chance
(100-year)
103,507 1% annual chance
(100-year)
81,490 1% annual chance
(100-year)
$73,043,916,760 Moderate
Hail Hail impacts from severe
weather events
All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident and condition of structures.
Economic losses can include building/infrastructure
damage; power outages; repairs to utility and power
lines
Moderate
Hurricane and
Tropical Storm
Categories 1-4 Storm
Surge Hazard Area
Category 1 Storm Surge: 66,290 Category 1 Storm Surge: 50,086 Category 1 Storm Surge: $45,671,691,795 Moderate
Category 2 Storm Surge: 129,076 Category 2 Storm Surge: 98,585 Category 2 Storm Surge: $87,001,755,597
Category 3 Storm Surge: 210,755 Category 3 Storm Surge: 144,078 Category 3 Storm Surge: $119,703,104,280
Category 4 Storm Surge: 265,843 Category 4 Storm Surge: 170,325 Category 4 Storm Surge: $138,655,890,684
Land Subsidence Rates of Elevation Loss
and Groundwater Levels
All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident and condition of structures.
Economic losses can include building/infrastructure
damage
Moderate
Lightning Lightning impacts from
severe weather events
All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident and condition of structures.
Economic losses can include building/infrastructure
damage; power outages; repairs to utility and power
lines
Moderate
Pandemic Pandemic include:
Influenza, West Nile
Virus, and Coronavirus.
Population impacted is dependent on the
disease and severity of the outbreak; in
some cases, immuno-compromised
persons are more vulnerable.
Structural impacts due to a pandemic
would be limited.
Economic losses can include County financial
impacts to monitor/address outbreaks; lost wages or
commercial interruptions; depends on the severity
and type of pandemic.
Moderate
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-178
2022 Update
Hazard of
Concern
Hazard/ Scenario Area
Evaluated Population Buildings Economya
Certainty
Factor
Severe Winter
Storm
Blizzard, Snow, Ice All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident and condition of structures.
The cost of snow and ice removal and repair of
roads/infrastructure can impact operating budgets.
Moderate
Thunderstorm
Wind
100-Year and 500-MRP
events
All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident and condition of structures.
100-Year MRP Estimated
Damages
$8,513,160,224 Moderate
500-Year MRP Estimated
Damages
$22,980,263,787
Tornadoes Tornadoes All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident and condition of structures.
Economic losses can include building/infrastructure
damage; power outages; repairs to utility and power
lines
Moderate
Tsunami Tsunami Hazard Area
(evacuation areas plus
high tide – 300 ft plus 22
ft.)
Population located in
Tsunami Hazard Area:
1,255 Buildings located in
Tsunami Hazard Area:
1,722 RCV of buildings in Tsunami
Hazard Area:
$3,204,780,207 Moderate
Wildfire Wildland-Urban
Interface/Intermix (WUI)
Wildfire Fuel Hazard
Areas
Population residing in the
WUI Interface:
1,254 Number of buildings the
WUI Interface:
1,173 Replacement cost value of
buildings located in the WUI
Interface:
$599,635,507 Moderate
Population residing in the
WUI Intermix:
1,973 Number of buildings the
WUI Intermix:
1,812 Replacement cost value of
buildings located in the WUI
Intermix:
$1,138,026,689
Utility Failure Utility Outages from
Hazard Events
All residents/commuters/visitors are
exposed; socially-vulnerable
populations may be at increased risk.
All buildings are exposed; the degree
of impact depends on the scale of the
incident.
Business and commercial losses due to long-term
utility outages; repairs to power and utility lines.
Moderate
Notes:
a Estimated loss in replacement cost values as available from HAZUS-MH.
b The impacts and vulnerability from a hazardous materials event are greatly dependent on the material and its physical and chemical properties, the quantity released,
weather conditions, micro-meteorological effects of buildings and terrain, maintenance/mechanical failures, and distance and related response time for emergency response
teams.
All totals for exposure values include all of Galveston County, including non-participating municipalities, CCDs, and unincorporated areas.
Exposed = This refers to the number of assets located in the hazard area; all of which may not incur losses as a result of the event.
MRP = Mean Return Period
SFHA = Special flood hazard area (1-percent annual chance flood event)
RCV = Replacement cost value based on 2021 RSMeans
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-179
2022 Update
4.4.2 Hazard Ranking Results
Using the process described above, the ranking for the identified hazards of concern was determined for
Galveston County (refer to Table 4-96). The hazard ranking is detailed in the subsequent tables that present the
stepwise process for the ranking. The countywide ranking includes the entire planning area and may not reflect
the highest risk indicated for any of the participating jurisdictions. The resulting ranks of each municipality
indicate the differing degrees of risk exposure and vulnerability. The results support the appropriate selection
and prioritization of initiatives to reduce the highest levels of risk for each municipality. Both the County and
the participating jurisdictions have applied the same methodology to develop the countywide risk and local
rankings to ensure consistency in the overall ranking of risk; jurisdictions had the ability to alter rankings based
on local knowledge and experience in handling each hazard.
This hazard ranking exercise serves four purposes: 1) to describe the probability of occurrence for each hazard;
2) to describe the impact each would have on the people, property, and economy; 3) to evaluate the capabilities
a community has with regards to the hazards of concern; and 4) to consider changing future conditions (i.e.,
climate change) in Galveston County.
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-180
2022 Update
Table 4-96. Ranking for Hazards of Concern for Galveston County
Hazard of
Concern
Probability
Impact
Adaptive
Capacity
Climate
Change
Population Property Economy
Total
Impact
Value Category
Numeric
Value Impact
Numeric
Value
Weighted
Value
(x3) Impact
Numeric
Value
Weighted
Value
(x2) Impact
Numeric
Value
Weighted
Value
(x1)
Coastal and
Inland Erosion Occasional 2 L 1 1 x 3 = 3 L 1 1 x 2 = 2 M 2 2 x 1 = 2 9 M H
Dam/ Levee
Failure Rare 1 M 2 2 x 3 = 6 M 2 2 x 2 = 4 L 1 1 x 1 = 1 12 M M
Drought Occasional 2 M 2 2 x 3 = 6 M 2 2 x 2 = 4 M 2 2 x 1 = 2 14 M H
Expansive Soils Rare 1 H 3 3 x 3 = 9 H 3 3 x 2 = 6 H 3 3 x 1 = 3 19 M M
Extreme
Temperature Frequent 3 M 2 2 x 3 = 6 L 1 1 x 2 = 2 L 1 1 x 1 = 1 12 M H
Flood Frequent 3 M 2 2 x 3 = 6 L 1 1 x 2 = 2 H 3 3 x 1 = 3 14 M H
Hail Occasional 2 L 1 1 x 3 = 3 M 2 2 x 2 = 4 L 1 1 x 1 = 1 10 M M
Hurricane and
Tropical Storm Occasional 2 H 3 3 x 3 = 9 H 3 3 x 2 = 6 H 3 3 x 1 = 3 20 M H
Land
Subsidence Rare 1 L 1 1 x 3 = 3 L 1 1 x 2 = 2 M 2 2 x 1 = 2 8 M M
Lightning Occasional 2 L 1 1 x 3 = 3 L 1 1 x 2 = 2 L 1 1 x 1 = 1 8 M M
Pandemic Occasional 2 M 2 2 x 3 = 6 L 1 1 x 2 = 2 M 2 2 x 1 = 2 12 M M
Severe Winter
Storm Rare 1 M 2 2 x 3 = 6 L 1 1 x 2 = 2 L 1 1 x 1 = 1 10 M M
Thunderstorm
Wind Occasional 2 M 2 2 x 3 = 6 M 2 2 x 2 = 4 M 2 2 x 1 = 2 14 M H
Tornadoes Occasional 2 M 2 2 x 3 = 6 M 2 2 x 2 = 4 M 2 2 x 1 = 2 14 M M
Tsunami Rare 1 L 1 1 x 3 = 3 L 1 1 x 2 = 2 L 1 1 x 1 = 1 7 M M
Wildfire Rare 1 L 1 1 x 3 = 3 L 1 1 x 2 = 2 L 1 1 x 1 = 1 7 M M
Utility Failure Frequent 3 M 2 2 x 3 = 6 L 1 1 x 2 = 2 M 2 2 x 1 = 2 13 M M
Section 4.4: Risk Ranking
Galveston County, TX | Hazard Mitigation Plan 4-181
2022 Update
Table 4-97 presents the total calculations for each hazard ranking value for the hazards of concern.
Table 4-97. Total Hazard Ranking Values for the Hazards of Concern for Galveston County
Hazard of Concern
Probability x
30%
Total Impact
x 30%
Adaptive
Capacity x 30%
Changing
Future
Conditions x
10%
Total Hazard
Ranking Value
Coastal and Inland Erosion 0.6 2.1 0 0.3 3.0
Dam/ Levee Failure 0.3 3.3 0 0.2 3.8
Drought 0.6 3.6 0 0.3 4.5
Expansive Soils 0.3 5.4 0 0.2 5.9
Extreme Temperature 0.9 2.7 0 0.3 3.9
Flood 0.9 3.3 0 0.3 4.5
Hail 0.6 2.4 0 0.2 3.2
Hurricane and Tropical Storm 0.6 5.4 0 0.3 6.3
Land Subsidence 0.3 2.1 0 0.2 2.3
Lightning 0.6 1.8 0 0.2 2.6
Pandemic 0.6 3 0 0.2 3.8
Severe Winter Storm 0.3 2.7 0 0.2 3.2
Thunderstorm Wind 0.6 3.6 0 0.3 4.5
Tornadoes 0.6 3.6 0 0.2 4.4
Tsunami 0.3 1.8 0 0.2 2.3
Wildfire 0.3 1.8 0 0.2 2.3
Utility Failure 0.9 3 0 0.2 4.1
Low = Values less than 3.9; Medium = Values between 3.9 and 4.9; High = Values greater than 4.9
These rankings have been used as one of the bases for identifying the jurisdictional hazard mitigation strategies
included in Section 9 (Jurisdictional Annexes) of this plan. The summary rankings for the County reflect the
results of the vulnerability analysis for each hazard of concern and vary from the specific results of each
jurisdiction. For example, the severe storm hazard may be ranked low in one jurisdiction, but due to the exposure
and impact countywide, it is ranked as a high hazard and is addressed in the County’s mitigation strategy
accordingly. Jurisdictional ranking results are presented in each local annex in Section 9 (Jurisdictional Annexes)
of this plan.
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-1
2022 Update
SECTION 5. CAPABILITY ASSESSMENT
According to FEMA’s Mitigation Planning How-To Guide #3, a capability assessment is an inventory of a
community’s missions, programs, and policies and an analysis of its capacity to carry them out. Each jurisdiction
has a unique set of capabilities available to accomplish mitigation and reduce long-term vulnerable to future
hazard events. Capabilities include authorities, policies, programs, staff, and funding. Reviewing existing
capabilities helps identify capabilities that currently implement mitigation and leads to loss reductions or that
have the potential to be implemented in the future.
This assessment is an integral part of the planning process. The assessment process enables identification,
review, and analysis of current federal, state, and local programs, policies, regulations, funding, and practices
that could either facilitate or hinder mitigation.
During the original planning process, the county and all jurisdictions identified and assessed their capabilities in
the areas of planning and regulatory, administrative, and technical, and fiscal. By completing this assessment,
the Planning Committee and each jurisdiction learned how or whether they would be able to implement certain
mitigation actions by determining the following:
• Limitations that could exist on undertaking actions.
• The range of local and state administrative, programmatic, regulatory, financial, and technical resources
available to assist in implementing their mitigation actions.
• Actions deemed infeasible, as they are currently outside the scope of capabilities.
• Types of mitigation actions that could be technically, legally (regulatory), administratively, politically,
or fiscally challenging or infeasible.
• Opportunities to enhance local capabilities to support long term mitigation and risk reduction.
During the 2022 plan update process, all participating jurisdictions were tasked with developing or updating
their capability assessment, paying particular attention to evaluating the effectiveness of these capabilities in
supporting hazard mitigation and identifying opportunities to enhance local capabilities to integrate hazard
mitigation into their plans, programs, and day-to-day operations.
County and municipal capabilities in the areas of planning and regulatory, administrative, and technical, and
fiscal may be found in the Capability Assessment section of their jurisdictional annexes in Section 9
(Jurisdictional Annexes).
5.1 UPDATE PROCESS SUMMARY
The purpose of the capability assessment is to understand the planning, regulatory, administrative, technical, and
financial capabilities present in Galveston County. This assessment helps the County and its jurisdictions identify
strengths and opportunities that can be used to reduce losses from hazard events and reduce risks throughout
Galveston County.
To complete the capability assessment, the contracted consultant met with Galveston County and each
municipality virtually to review the capability assessment from the 2016 HMP and update accordingly. In
addition to virtual meetings, the consultant reviewed plans and codes/ordinances to enhance the information
provided by the jurisdictions.
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-2
2022 Update
A summary of the various federal and state capabilities available to promote and support mitigation and reduce
risk in Galveston County are presented below. Information provided by the County and municipalities are
presented in Volume II, Section 9 (Jurisdictional Annexes) of this plan update.
5.2 PLANNING AND REGULATORY CAPABILITY
Planning and regulatory capabilities are based on the implementation of ordinances, policies, local laws, and
state statutes, and plans and programs that relate to guiding and management growth and development. Planning
and regulatory capabilities refer not only to the current plans and regulations, but also to the jurisdiction’s ability
to change and improve those plans and regulations as needed. The following provides the planning and
regulatory capabilities for Galveston County.
5.2.1 Planning and Regulatory Capabilities – County and Local
The following table summarizes the planning and regulatory capabilities available to Galveston County, at the
county and local level.
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-3
2022 Update
Table 5-1. Planning and Regulatory Capabilities – County and Local
Capability Details
Building Code Description: The County is governed by the Texas Administrative Code § 5.4008 The 2018 International Building Code (IBC)
The 2018 International Residential Code (IRC) NFPA. By using the IRC, IBC and NFPA, the highest standards are
assured for County construction to reduce the risk of hazards and protect both lives and property
Responsible Agency: Texas Department of Insurance
Provides Funding for Mitigation: No
Hazard: All hazards
Subdivision Ordinance - Rules,
Regulations and Requirements
Relating to the Approval and
Acceptance of Improvements in
Subdivisions or Re-Subdivisions –
3/3/1997 – last revised – 10/3/2005
Description: Major drainage ways through a subdivision shall be designed and constructed to accommodate the 100 -year peak rate
of runoff, in the manner prescribed by the applicable Galveston County Drainage District and the Galveston County
Engineer.
The following requirements shall apply to all developments planned within the 100-year flood plain:
1. Any construction and/or fill that would obstruct flow and cause any increase in flood levels must be fully offset with
conveyance improvements.
2. Flood plain storage volumes shall not be reduced by way of fill. Where flood plain fill is proposed and is demonstrated
not to adversely affect conveyance, compensatory storage equal in volume and effect shall be excavated.
Responsible Agency: County Engineer
Provides Funding for Mitigation: No
Hazard: Flood
Stormwater Management - Storm
Water MS4 Pollution Control
Order 2012
Description: Stormwater Management reduces the risk of pollutants that may have the potential to endanger local residents through
inspection and enforcement of the MS4 regulations.
Responsible Agency: Galveston County Health Department
Provides Funding for Mitigation: No
Hazard: Flood
Real Estate Disclosure - Texas
Property Code Section § 5.008 -
Seller’s Disclosure of Property
Condition
Description: Real Estate Disclosure ensures that property owners are aware of historical disaster impacts and gives them information
necessary to plan for and mitigate future disasters
Responsible Agency: Texas Real Estate Commission
Provides Funding for Mitigation: No
Hazard: Flood
Flood Damage Prevention -
Galveston County Floodplain
Regulations August 2019
Description: Floodplain regulations reduce risk to lives and property by ensuring mitigation measures are put into place for repetitive
loss properties and new construction.
Responsible Agency: Galveston County Engineer
Provides Funding for Mitigation: No
Hazard: Flood
Emergency Management - Texas
Government Code Chapter 418
Description: Emergency Management requirements provide for the planning, mitigation, preparedness, response, and recovery
activities necessary for a high impact coastal community.
Responsible Agency: Texas Division of Emergency Management
Provides Funding for Mitigation: No
Hazard: All hazards
Capital Improvement Plan -
Fiscal Year 2021 – Annual
Operating Budget
Description: The County encourages departments to submit two to five year capital plans for approval by the Commissioners Court.
Approved plans shall be given priority during the annual budget process. Capital spending is reserved for major
renovation, building, or road and bridge related projects that are planned for the fiscal year.
Responsible Agency: Commissioners Court
Provides Funding for Mitigation: Yes
Hazard: Flood, Severe Winter Storm, Hurricane, Utility Failure
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-4
2022 Update
Capability Details
Galveston County Debris
Management Plan
Description: Planning in advance for the removal and management of disaster related debris reduces the risk to lives and property
from dangerous debris and vermin and begins the rebuilding process for the entire community.
Responsible Agency: County Road and Bridge Department
Provides Funding for Mitigation: No
Hazard: Flood, Hurricane
Open Space Plan - Parks,
Recreation, Open Space, and
Conservation/Natural Resource
Master Plan – January 2012 – 2017
Draft
Description: The destruction caused to much of Galveston County’s coastal wildlife habitat and recreation areas in September 2008,
has enhanced the need to prepare a new Master Plan that reflects current circumstances.
This Master Plan document establishes the guidelines which will direct the acquisition and development of parks,
recreation areas, and open spaces for the next eight years. The Master Plan Drawing illustrates the general type and
location of recommended parks and open spaces This document also includes specific recommendations for future land
acquisition, park development and natural resources conservation initiatives to serve the growing population and needs
of Galveston County residents.
Responsible Agency: County Parks and Recreation Department
Provides Funding for Mitigation: No
Hazard: Flood
Galveston County Dune
Protection and Beach Access
Plan
Description: Shoreline management reduces the risk to lives and property through regulations designed to minimize the impact of
natural hazards and manmade activities to the coastal environment
Responsible Agency: General Land Office
Provides Funding for Mitigation: No
Hazard: Flood
Texas Agri-Life Extension
Service
Description: Agricultural planning reduces the risk to the animals and community during times of disaster.
Responsible Agency: Galveston County Agricultural Extension
Provides Funding for Mitigation: No
Hazard: Flood, Hurricane, Severe Winter Storm
Galveston County Emergency
Management Plan 2017
Description: The Galveston County Emergency Management Plan details both short-term response and long-term recovery plans that
address communications, evacuation, and housing necessary for a variety of hazards that impact the community.
Responsible Agency: Galveston County Office of Emergency Management.
Provides Funding for Mitigation: No
Hazard: All Hazards
Post-Disaster Recovery Plan –
Annex J
Description: By preparing for recovery in advance, potential impact from hazards can be mitigated through planned response and
recovery activities
Responsible Agency: GCOEM and Long Term Recovery Group
Provides Funding for Mitigation: No
Hazard: All Hazards
5.2.2 Planning and Regulatory Capabilities – Federal and State
The following table summarizes the planning and regulatory capabilities available to Galveston County, at the federal and state level.
Table 5-2. Planning and Regulatory Capabilities – Federal and State
Capability Details
Disaster Mitigation Act (DMA) Description: The DMA is the current federal legislation addressing hazard mitigation planning. It emphasizes planning for disasters
before they occur. It specifically addresses planning at the local level, requiring plans to be in place before Hazard
Mitigation Assistance grant funds are available to communities. This plan is designed to meet the requirements of DMA,
improving eligibility for future hazard mitigation funds.
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-5
2022 Update
Capability Details
Responsible Agency: FEMA
Provides Funding for Mitigation: HMPs designed to meet the requirements of DMA will remain eligible for future FEMA Hazard Mitigation Assistance
funds
Hazard: All-natural hazards
National Flood Insurance
Program (NFIP)
Description: The NFIP is a federal program enabling property owners in participating communities to purchase insurance as a
protection against flood losses in exchange for state and community floodplain management regulations that reduce
future flood damages. The Flood Hazard Profile in Section 4.3.6 (Flood) provides information on recent legislation
related to reforms to the NFIP.
All municipalities in Galveston County actively participate in the NFIP. As of September 2021, there were 62,867
policies in Galveston County. There have been 55,196 claims made, totaling over $2 billion for damages to structures
and contents.
Responsible Agency: FEMA
Provides Funding for Mitigation: Full compliance and good standing under the NFIP are application prerequisites for all FEMA grant programs for which
participating jurisdictions are eligible under this plan.
Hazard: Flood
NFIP Community Rating System
(CRS)
Description: As an additional component of the NFIP, CRS is a voluntary incentive program that recognizes and encourages
community floodplain management activities that exceed the minimum NFIP requirements. As a result, flood insurance
premium rates are discounted to reflect the reduced flood risk resulting from the community actions meeting the three
goals of the CRS: (1) reduce flood losses, (2) facilitate accurate insurance rating, and (3) promote the awareness of flood
insurance. Municipalities, and the county as a whole, could expect significant cost savings on premiums if enrolled in
the CRS program. As of October 2021, 7 communities in Galveston County participate in the CRS program.
• City of Dickinson, Class 8
• City of Friendswood, Class 7
• City of Galveston, Class 6
• City of Jamaica Beach, Class 8
• City of Kemah, Class 8
• City of League City, Class 5
• Village of Tiki Island, Class 7
Other communities in Galveston County have noted they are exploring the possibility of participating in the program in
the future.
Responsible Agency: FEMA
Provides Funding for Mitigation: CRS premium discounts on flood insurance range from 5 percent for Class 9 communities up to 45 percent for Class 1
communities.
Hazard: Flood
Local Government Code
Title 7. Regulation Of Land Use,
Structures, Businesses, and
Related Activities
Subtitle A. Municipal Regulatory
Authority
Chapter 211. Municipal Zoning
Authority
Description: The powers granted under this subchapter are for the purpose of promoting the public health, safety, mor als, or general
welfare and protecting and preserving places and areas of historical, cultural, or architectural importance and
significance. The governing body of a municipality may regulate the size of buildings and other structures, lot coverage,
size of open spaces, population density, the location and use of buildings and groundwater use.
Zoning regulations must be adopted in accordance with a comprehensive plan and must be designed to:
(1) lessen congestion in the streets.
(2) secure safety from fire, panic, and other dangers.
(3) promote health and the general welfare.
(4) provide adequate light and air.
(5) prevent the overcrowding of land.
(6) avoid undue concentration of population; or
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-6
2022 Update
Capability Details
Subchapter A. General Zoning
Regulations
(7) facilitate the adequate provision of transportation, water, sewers, schools, parks, and other public requirements.
The governing body of a municipality may divide the municipality into districts of a number, shape , and size the
governing body considers best for carrying out this subchapter. Within each district, the governing body may regulate
the erection, construction, reconstruction, alteration, repair, or use of buildings, other structures, or land.
Zoning regulations must be uniform for each class or kind of building in a district, but the regulations may vary from
district to district. The regulations shall be adopted with reasonable consideration, among other things, for the character
of each district and its peculiar suitability for particular uses, with a view of conserving the value of buildings and
encouraging the most appropriate use of land in the municipality.
.
Responsible Agency: State of Texas
Provides Funding for Mitigation: No
Hazard: All Hazards
Texas Silver Jackets Description: Silver Jackets is a program under National Flood Risk Management Program to support agency collaboration and
coordination with interagency, state-led flood risk and multiple hazard management teams. Provides resources and
develops tools to support information sharing and networking and promotes implementation of flood risk management
efforts that improve flood risk awareness and result in actions to reduce risk. For more information:
http://silverjackets.nfrmp.us/
Responsible Agency: US Army Corp of Engineers
Provides Funding for Mitigation: No
Hazard: Flood
Texas General Land Office Description: The Texas General Land Office (GLO), through the Community Development and Revitalization division, works to
rebuild Texas communities by putting Texans back in their homes, restoring critical infrastructure and mitigating future
damage through resilient community planning. The GLO is setting a record pace administering both Community
Development Block Grant Disaster Recovery (CDBG-DR) and Mitigation (CDBG-MIT) funds from the U.S.
Department of Housing and Urban Development (HUD) on behalf of the state of Texas.
More than $14 billion have been allocated for recovery and mitigation following Hurricanes Rita, Dolly, and Ike, the
2011 wildfires, the 2015 and 2016 floods, Hurricane Harvey, the 2018 South Texas floods, and the 2019 disasters. These
grants can be used for a wide variety of activities including housing redevelopment, infrastructure repair and long-term
planning, depending on HUD guidance.
Responsible Agency: Texas General Land Office
Provides Funding for Mitigation: Yes
Hazard: Flood, Hurricane, Wildfire
Coastal Erosion Planning and
Response Act (CEPRA)
Description: The average erosion rate for the 367 miles of Texas coast is 4.1 feet per year. Sixty-four percent of the Texas coast is
eroding at an average rate of about 6 feet per year, with some locations losing more than 30 feet per year. FEMA
estimates that every dollar spent on erosion control and mitigation to preserve wetlands and other natural ecosystems,
will provide a return on average of $4 in future cost-savings.
Since 2000, the GLO’s Coastal Erosion Planning and Response Program has received $111.4 million in state -
appropriated funding. Project partners (local governments, non-profits, state, and federal entities) have contributed $52
million in non-federal matching funds and in-kind contributions, along with $165.2 million in federal funds and in-kind
contributions that have resulted in more than 355 coastal erosion response projects.
Responsible Agency: General Land Office
Provides Funding for Mitigation: Yes
Hazard: Flood, Hurricane, Land Subsidence
Coastal Management Program
(CMP)
Description: Texas receives approximately $2 million annually in grants from National Oceanic and Atmospheric Administration
(NOAA) and 90% of the funds are passed through to local governments and entities to address environmental needs and
promote sustainable economic development along the coast. Projects must improve the management of the state’s coastal
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-7
2022 Update
Capability Details
resources and ensure long-term ecological and economic productivity. Section 306 administrative funds can be used for
non-construction, coastal planning and education, and research. Section 306A improvement funds can be utilized for
construction and land acquisition projects and preservation and restoration.
CMP funding categories include Coastal Natural Hazards Response, Critical Areas Enhancement, Public Access,
Water/Sediment Quantity and Quality Improvements, Waterfront Revitalization and Ecotourism Development, Permit
Streamlining/Assistance, Governmental Coordination and Local Government Planning Assistance.
Responsible Agency: Texas General Land Office
Provides Funding for Mitigation: Yes
Hazard: Flood, Hurricane
Gulf of Mexico Energy Security
Act (GOMESA)
Description: GOMESA significantly enhances oil and gas leasing activities and creates revenue sharing provisions for the oil- and
gas-producing states of Alabama, Louisiana, Mississippi, and Texas, and their coastal political subdivisions (CPSs).
GOMESA funds are used for coastal conservation, restoration, and hurricane protection. The second phase of GOMESA
revenue sharing began in Fiscal Year 2017 and expands the definition of qualified Outer Continental Shelf revenues to
include receipts from Gulf of Mexico leases subject to withdrawal or moratoria restrictions. A revenue -sharing cap of
$500 million per year for the four Gulf producing states, their CPSs and the Land and Water Conservation Fund applies
from fiscal years 2016 through 2055. The $500 million cap does not apply to qualified revenues generated in those areas
associated with Phase I of the GOMESA program. From 2009 through 2016, the state of Texas received $3,192,269 and
its 18 CPSs received $798,036.
The goal of GOMESA funding is to conserve, restore, enhance, and protect the diversity, quality, quantity,
functions, and values of the state’s coastal natural resources. A primary focus for the GLO will be to
protect coastal natural resources while facilitating multiple human uses of coastal resources.
The GLO’s priority for the expenditures of GOMESA funds include:
1. Restoring and enhancing coastal natural resources.
2. Providing hurricane protection for coastal public resources.
3. Improving water quality.
4. Enhancing the balance between the protection of coastal natural resources and public use of
those resources.
5. Improving environmental management; and
6. Mitigating coastal erosion and stabilizing shorelines.
Responsible Agency: Texas General Land Office
Provides Funding for Mitigation: Yes
Hazard: Flood, Hurricane, Manmade Disasters
U.S. Army Corps of Engineers –
Dam Safety Program
Description: The U.S. Army Corps of Engineers (USACE) is responsible for safety inspections of some federal and non-federal dams
in the United States that meet the size and storage limitations specified in the National Dam Safety Act. USACE has
inventoried dams and has surveyed each state and federal agency’s capabilities, practices, and regulations regarding
design, construction, operation, and maintenance of the dams. USACE has also developed guidelines for inspection and
evaluation of dam safety (USACE 1997).
Responsible Agency: USACE
Provides Funding for Mitigation: Yes
Hazard: Flood
Natural Resources Damage
Assessment (NRDA)
Description: The natural resource trustees are the designated federal, state, and tribal agencies who are
responsible for the natural resources impacted by an oil spill or hazardous substance release.
They have common interests in sharing information, ideas, and expertise necessary to compensate the
public for harm to natural resources as a result of oil spills and hazardous substance releases.
Three Texas state agencies have been designated by the Governor to
Responsible Agency: Texas Commission on Environmental Quality
SECTION 5: CAPABILITY ASSESSMENT
Galveston County, TX | Hazard Mitigation Plan 5-8
2022 Update
Capability Details
Provides Funding for Mitigation: Yes
Hazard: Manmade Disasters
Coastal and Estuarine Land
Conservation Program (CELCP)
Description: Lands being targeted for protection through TCELCP include coastal and estuarine areas with
significant ecologic, conservation, recreation, historic, and aesthetic values. Many of these lands
are threatened by conversion from their natural state to other uses. This section describes the
geographic extent of the TCELCP boundary, outlines the types of lands and values to be
protected, and gives an assessment of their status and trends (when known), functions and
values, and potential threats.
When NOAA provides funding for CELCP, the GLO provides coastal communities an opportunity to apply
for up to three projects per year, with federal grants for any single project not to exceed $3
million.
Responsible Agency: NOAA, Texas General Land Office
Provides Funding for Mitigation: Yes
Hazard: Flood, Hurricane
Texas Division of Emergency
Management
Description: TDEM is charged with carrying out a comprehensive, all-hazard emergency management program for the state and
assisting cities, counties, and state agencies in implementing their own emergency management programs
Responsible Agency:
Provides Funding for Mitigation: No
Hazard: All Hazards
Community Health and Resource
Management (CHARM)
Description: CHARM is directed by the Texas Coastal Watershed Program, a part of Texas A&M AgriLife Extension Service. It is
a mapping application that gives local officials, stakeholders, and citizens the power to analyze growth with real -time
feedback. Using the weTable tool that transforms an ordinary tabletop into an interactive computer interface, CHARM
allows participants to engage the public and gather their input regarding the community’s future. The mapping
application is supported by a library of data about urbanization, storm surge, conservation, public facilities, and coastal
resources. The CHARM application can leverage local knowledge for better long-term planning, and is an ideal tool for
communities, watersheds, and environmental projects.
Responsible Agency: Texas A&M AgriLife Extension Service.
Provides Funding for Mitigation: No
Hazard: Flood
Home Program Description: The Texas Department of Housing and Community Affairs (TDHCA) administers the HOME Program on behalf of
the state. The purpose of the program is to expand the supply of
328 State of Texas Hazard Mitigation Plan 2018 |TDEM
decent, safe, affordable housing and strengthen public-private housing partnerships between units of local
governments, public housing authorities, nonprofits, and for profit entities. TDHCA has set aside funding for Disaster
Relief and Persons with Disabilities, among others.
Responsible Agency: TDHCA
Provides Funding for Mitigation: Yes
Hazard: All Hazards
Texas Water Development Board
(TWDB) – Flood Insurance
Program
Description: TWDB is the state agency charged with collecting and disseminating water-related data, assisting with regional
planning, preparing the State Water Plan, which addresses the development of the state‘s water resources. The agency
also administers cost-effective financial assistance programs for the construction of water supply, wastewater
treatment, flood control and agricultural water conservation projects. The TWDB has made great strides in floodplain
management since the last update to the 2013 SHMP. Examples include hiring full time staff to manage the State’s
Cooperating Technical Partner floodplain mapping program, developing a State Flood Plan (see below for information
on both), and creating a website to assist citizens and first responders during a flood event (www.TexasFloods.org).
The following is a list of programs available which may assist with flooding and the mitigation of Repetitive and
Severe Repetitive Loss properties.
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TWDB’s National Flood Insurance Program group conducts Community Assistance Visits (CAV), Community
Assistance Contacts (CAC), and floodplain management training to assist communities with maintaining NFIP
compliance and sound floodplain management practices.
The CAV is a scheduled visit to an NFIP community for the purpose of conducting a comprehensive assessment of the
community's floodplain management program and evaluating its knowledge and understanding of the requirements of
the NFIP. The purpose of the CAV is also to assist the community in understanding NFIP requirements when program
deficiencies are discovered.
Floodplain Management 101 workshops are offered to local officials and other interested parties which cover the NFIP
and various flood loss reduction techniques and strategies, such as the Community Rating System (CRS). The
workshops contain training modules on the Texas Water Code, Elevation Certificates, FEMA requirements,
community awareness, map reading, permitting, and ordinance comprehension.
Responsible Agency: TWDB
Provides Funding for Mitigation: Yes
Hazard: Flood
Cooperation Technical Partners
(CTP)
Description: TWDB also administers the FEMA Cooperating Technical Partners (CTP) Program, which allows communities, tribal
nations, universities, and regional and state agencies to be active partners in FEMA’s flood hazard mapping program.
The CTP program at the state level aims to produce flood risk information through leveraging state and local funds,
updated flood risk products, and coordination between statewide cooperating technical partners.
Responsible Agency: TWDB
Provides Funding for Mitigation: No
Hazard: Flood
Fund Development Program Description: TWDB also administers the Fund Development Program to provide loans for the planning, design, and construction of
water supply, wastewater, and flood control projects. Structural flood protection improvements may include construction
of storm water retention basins, the enlargement of stream channels public beach re-nourishment, the control of coastal
erosion, and the modification or reconstruction of bridges. Non-structural flood protection improvements may include
the acquisition of floodplain properties for use as public open space, the acquisition and removal of buildings and
residents located within a floodplain, flood warning systems, and the development of floodplain management plans. The
agency conducts an environmental review for all construction projects.
Responsible Agency: TWBD
Provides Funding for Mitigation: Yes
Hazard: Flood
Texas Natural Resources
Information System (TNRIS)
Description: The Texas Natural Resources Information System (TNRIS) is a division of TWDB, and is responsible for producing,
archiving, and distributing geographic data to agencies, businesses, and the public. TNRIS supports hazard mitigation
planning and implementation in three ways:
• Provides data to organizations for planning or response activities.
• Develops, locates, and prepares data for specific needs and/or projects.
• Updates the State Critical Facility Database.
Responsible Agency: TWDB
Provides Funding for Mitigation: No
Hazard: All Hazards
Texas Flash Flood Coalition Description: The TFFC is an organization dedicated to decreasing the number of deaths caused by flash flooding in Texas. More
than 30 representatives of higher education, media, private industry, local, state, and federal governments participate in
the coalition. Its strategy is to:
• Brainstorm and share ideas, data, resources, and best practices
• Include a diversity of folks from all levels of education, the public, private entities, and academia
• Attack the flash flood problem with mitigation, research, technology, education, awareness, warning, and
communication
Responsible Agency: Works with the Texas Floodplain Management Association
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Capability Details
Provides Funding for Mitigation: No
Hazard: Flood, Flash Flood
Community Hazard Analysis and
Mitigation Planning Support
(CHAMPS)
Description: The CHAMPS reports are summarized descriptions of historical hazard events and future hazard risks for each county
in Texas. These have been developed by the Texas Geographic Society in a project funded by FEMA and a dministered
by TDEM. CHAMPS reports have been developed to provide local mitigation planners with data, maps, and other
information they can use to support the hazard assessment portion of the mitigation planning process.
Each report includes information on county populations and built environments, historical losses from multiple hazards,
and expected future likelihood of more hazard events. Also included with every hazard is a comparative display showing
how the number of hazard events in that county compares with the number of events in other counties for that hazard
over the same timeframe.
Responsible Agency: Texas Geographic Society
Provides Funding for Mitigation: No
Hazard: All Hazards
Urban Tree Canopy Project –
Resilient Landscapes Program
Description: TFS has programs and funding opportunities, such as the Urban Tree Canopy Project, that address mitigation by
decreasing impact from summer heat, flooding, and erosion. The Fire-Adapted Communities Program provides cost-
share funds to assist in informing and preparing citizens to safely co-exist with wildland fire. The Resilient Landscapes
Program provides cost-share reimbursement funds to restore healthy, fire-adapted ecosystems. The Firewise USA
Program provides cost-share funds in cooperation with the National Fire Protection Administration to encourage
homeowners to take individual responsibility for protecting their homes from the risk of wildfire.
Responsible Agency: Texas A&M Forest Service
Provides Funding for Mitigation: No
Hazard: Wildfires
Texas Department of Licensing
and Regulation
Description: Licenses and regulates weather modification programs and hosts the Texas Weather Modification and Advisory
Committee meetings. Cloud seeding projects designed to increase rainfall from convective cloud towers are conducted
in nearly 31 million acres of Texas. In administering the Texas Weather Modification Act, TDLR’s weather modification
program issues license and permits for projects using specialized aircraft and sophisticated weather radar systems at sites
near Amarillo, San Angelo, and Pleasanton. TDLR also issues permit for hail suppression projects.
Responsible Agency: TDLR
Provides Funding for Mitigation: No
Hazard: Drought
Texas Department of
Transportation
Description: TXDOT incorporates tornado safe rooms into their Safe Rest Stops program through a federally-funded Transportation
Enhancement program (See Section 6.3). TXDOT also revises its design manual to include improved guidance on NFIP
requirements. The agency supports the effort to certify floodplain managers by encouraging all their personnel to become
certified. All engineers in TxDOT’s central hydraulics branch are certified.
Responsible Agency: TxDOT
Provides Funding for Mitigation: No
Hazard: Flood
Texas Residential Safe Room
Rebate Program
Description: TDEM, through the Hazard Mitigation Assistance (HMA) grants, began offering a rebate incentive for builders and
homeowners to build or install residential safe rooms. This program is implemented by local un its of government that
choose to administer the program through a grant provided through the HMGP or PDM program. TDEM has also
published a residential safe room handbook to assist local jurisdictions with the implementation of the program. This
program has raised the viability and the visibility of safe rooms in high tornado/windstorm regions of Texas.
Responsible Agency: TDEM
Provides Funding for Mitigation: Yes
Hazard: Tornado, Windstorm
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5.3 ADMINISTRATIVE AND TECHNICAL CAPABILITIES
Table 6-3 summarizes the administrative and technical capabilities in Galveston County. Detailed information regarding administrative and te chnical
capabilities in the County and the municipalities can be found in each jurisdictional annex found in Volume II, Section 9 (Jurisdictional Annexes).
Table 5-3. Administrative and Technical Capability – County and Local
Capability Details
Road and Bridge Department Description: The Road and Bridge Department is responsible for the maintenance of all county roads, road drainage, bridges and
bridge class culverts and road signage. Road signs are maintained to the TMUTCD standard and inspections are
completed regularly. The maintenance of county roads includes the reclamation of existing materials, placing new
materials, surface treatments, and paving. The Road and Bridge Department is responsible for debris management for
post disaster events and emergencies. The Department’s administrative responsibilities include providing customer
service, departmental budgeting and procurement, correspondence, maintenance documentation and other administrative
services.
Goals & Objectives
• Provide the highest level of customer service by meeting the needs of the public traveling the county roads.
• Provide the highest level of quality while controlling cost and expenditures, detail maintenance records for
all roads, drainage systems, bridges, and signage.
• Provide assistance within Galveston County to cities, villages and other entities for road rehabilitation and
drainage work through Inter-local Agreements.
Responsible Agency: County
Provides Funding for Mitigation: No
Hazard: Flood, Hurricane, Severe Winter Storm
Parks and Cultural Services
Department
Description: Galveston County parks are host to more than a half-million residents and visitors each year and home to a wealth of
wildlife. Within the Galveston County parks system there is approximately 1,500 wonderful acres of recreational
parkland nestled in the county’s neighborhoods for residents and visitors to enjoy. There are currently 20 parks and three
undeveloped parkland areas, 10 public boat ramps, countless amenities and an impressive assortment of indoor and
outdoor rental facilities that are easily accessible and expertly managed and maintained.
The Parks Department also oversees the County’s Senior Program.
Responsible Agency: County
Provides Funding for Mitigation: No
Hazard: Flood
Facilities and Maintenance
Department
Description: The Department’s mission is to provide a safe and comfortable environment for all employees and visitors to the
Galveston County facilities. To maximize the efficiency and life span of all equipment and building systems associated
with the facilities.
Responsible Agency: County
Provides Funding for Mitigation: No
Hazard: No
Office of Emergency
Management
Description: Galveston County’s state-of-the-art emergency operations facility came online in October 2005 and was the first in the
nation to combine a National Weather Service office with an emergency management department of local government.
The 23,500-square-foot building was designed to withstand a Category 5 hurricane.
Each county is required to maintain an emergency management program or participate in an inter-jurisdictional
emergency management program as defined in Section 418.102 of the Texas Government Code. Chapter 418 of the
Texas Government Code is also referred to as the Texas Disaster Act of 1975. The county is selected to be the “first
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Capability Details
channel” through which municipalities request resources when their own resources have been depleted. The county
forwards any resource requests beyond county capabilities to the state.
The EMO facility provides Galveston County with a sustainable central location for the county during the emergency
management cycle. Rather than operating from multiple facilities to get the job done, emergency operations and resource
procurement can take place with county employees face-to-face rather than wasting time with phone calls and e-mails.
Saving time during an emergency ultimately saves money.
Responsible Agency: County
Provides Funding for Mitigation: No
Hazard: All Hazards
Department of Engineering and
Right of Way
Description: The Engineering and Right of Way Department is responsible for reviewing building permit applications for consistency
with the Building Code, Flood Regulations, Dune Protection, Drainage, and Erosion Response Plan. The Department
enforces the Subdivision regulations and issues Road Crossing permits.
Responsible Agency: County
Provides Funding for Mitigation: No
Hazard: Flood, Hurricane
5.4 FISCAL CAPABILITIES
Fiscal capabilities are the resources that a jurisdiction has access to or is eligible to use to fund mitigation actions. Th e table below provides a list of
programs, descriptions, and links for those jurisdictions seeking funding sources. This table is not intended to be a comprehensive list, but rather a tool to
help begin identifying potential sources of funding.
Table 5-4. Fiscal Capabilities
Capability Details
Federal
Hazard Mitigation Grant
Program
Description: The HMGP is a post-disaster mitigation program. It is made available to states by FEMA after each Federal disaster declaration. The
HMGP can provide up to 75% funding for hazard mitigation measures. The HMGP can be used to fund cost-effective projects that
will protect public or private property in an area covered by a federal disaster declaration or that will reduce the likely damage from
future disasters. Examples of projects include acquisition and demolition of structures in hazard prone areas, flood-proofing, or
elevation to reduce future damage, minor structural improvements, and development of state or local standards. Projects must fit into
an overall mitigation strategy for the area identified as part of a local planning effort. All applicants must have a FEMA-approved
Hazard Mitigation Plan (this plan).
Applicants who are eligible for the HMGP are state and local governments, certain nonprofit organizations or institutions that perform
essential government services, and Indian tribes and authorized tribal organizations. Individuals or homeowners cannot apply directly
for the HMGP; a local government must apply on their behalf. Applications are submitted to TDEM and placed in rank order for
available funding and submitted to FEMA for final approval. Eligible projects not selected for funding are placed in an inactive status
and may be considered as additional HMGP funding becomes available.
For additional information regarding HMGP, please refer to: https://www.fema.gov/hazard-mitigation-grant-program
Responsible Agency: FEMA
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Capability Details
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Flood Mitigation Assistance
Program
Description: The FMA program combines the previous Repetitive Flood Claims and Severe Repetitive Loss Grants into one grant program. The
FMA provides funding to assist states and communities in implementing measures to reduce or eliminate the long-term risk of flood
damage to buildings, manufactured homes, and other structures insurable under the NFIP. The FMA is funded annually; no federal
disaster declaration is required. Only NFIP insured homes and businesses are eligible for mitigation in this program. Funding for FMA
is very limited and, as with the HMGP, individuals cannot apply directly for the program. Applications must come from local
governments or other eligible organizations. The federal cost share for an FMA project is at least 75 percent. For the nom-federal
share, at most 25 percent of the total eligible costs must be provided by a non-federal source; of this 25 percent, no more than half can
be provided as in-kind contributions from third parties. At minimum, a FEMA-approved local flood mitigation plan is required before
a project can be approved. The FMA funds are distributed from FEMA to the state. TDEM serves as the grantee and program
administrator for the FMA program. The FMA program is detailed on the FEMA website: https://www.fema.gov/flood-mitigation-
assistance-grant-program.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: Flood, Severe Weather
Building Resilient
Infrastructure and
Communities Program
Description: Building Resilient Infrastructure and Communities (BRIC) will support states, local communities, tribes, and territories as they
undertake hazard mitigation projects, reducing the risks they face from disasters and natural hazards. BRIC is a new FEMA pre-
disaster hazard mitigation program that replaces the existing Pre-Disaster Mitigation (PDM) program.
The BRIC program guiding principles are supporting communities through capability- and capacity-building; encouraging and
enabling innovation; promoting partnerships; enabling large projects; maintaining flexibility; and providing consistency.
For additional information regarding the BRIC program, please refer to: https://www.fema.gov/grants/mitigation/building-resilient-
infrastructure-communities
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Extraordinary Circumstances Description: For PDM and FMA project subawards, the (FEMA) Region may apply extraordinary circumstances when justification is provided and
with concurrence from FEMA Headquarters (Risk Reduction and Risk Analysis Divisions) prior to granting an exception. If this
exception is granted, a local mitigation plan must be approved by FEMA within 12 months of the award of the project subaward to
that community.
For HMGP, PDM, and FMA, extraordinary circumstances exist when a determination is made by the Applicant and FEMA that the
proposed project is consistent with the priorities and strategies identified in the State (Standard or Enhanced) Mitigation Plan and that
the jurisdiction meets at least one of the criteria below. If the jurisdiction does not meet at least one of these criteria, the Region must
coordinate with FEMA Headquarters (Risk Reduction and Risk Analysis Divisions) for HMGP; however, for PDM and FMA the
Region must coordinate and seek concurrence prior to granting an exception:
•The jurisdiction meets the small, impoverished community criteria (see Part VIII, B.2).
•The jurisdiction has been determined to have had insufficient capacity due to lack of available funding, staffing, or other necessary
expertise to satisfy the mitigation planning requirement prior to the current disaster or application deadline.
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•The jurisdiction has been determined to have been at low risk from hazards because of low frequency of occurrence or minimal
damage from previous occurrences as a result of sparse development.
•The jurisdiction experienced significant disruption from a declared disaster or another event that impacts its ability to complete the
mitigation planning process prior to award or final approval of a project award.
•The jurisdiction does not have a mitigation plan for reasons beyond the control of the State, federally-recognized tribe, or local
community, such as Disaster Relief Fund restrictions that delay FEMA from granting a subaward prior to the expiration of the local or
Tribal Mitigation Plan.
For HMGP, PDM, and FMA, the Applicant must provide written justification that identifies the specific criteria or circumstance listed
above, explains why there is no longer an impediment to satisfying the mitigation planning requirement, and identifies the sp ecific
actions or circumstances that eliminated the deficiency.
When an HMGP project funding is awarded under extraordinary circumstances, the Recipient shall acknowledge in writing to the
Regional Administrator that a plan will be completed within 12 months of the subaward. The Recipient must provide a work plan for
completing the local or Tribal Mitigation Plan, including milestones and a timetable, to ensure that the jurisdiction will complete the
plan in the required time. This requirement shall be incorporated into the award (both the planning and project subaward agreements,
if a planning subaward is also awarded).
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Individual Assistance Description: Individual Assistance (IA) provides help for homeowners, renters, businesses, and some non-profit entities after disasters occur. This
program is largely funded by the U.S. Small Business Administration. For homeowners and renters, those who suffered uninsured or
underinsured losses could be eligible for a Home Disaster Loan to repair or replace damaged real estate or personal property. Renters
are eligible for loans to cover personal property losses. Individuals are allowed to borrow up to $200,000 to repair or repla ce real
estate, $40,000 to cover losses to personal property, and an additional 20 percent for mitigation. For businesses, loans could be made
to repair or replace disaster damages to property owned by the business, including real estate, machinery and equipment, inventory,
and supplies. Businesses of any size are eligible. Non-profit organizations, such as charities, churches, and private universities are
eligible. An Economic Injury Disaster Loan provides necessary working capital until normal operations resume after a physical
disaster but are restricted by law to small businesses only. IA is detailed on the FEMA website: https://www.fema.gov/individual-
disaster-assistance.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Public Assistance Description: Public Assistance (PA) provides cost reimbursement aid to local governments (state, county, local, municipal authorities, and school
districts) and certain non-profit agencies that were involved in disaster response and recovery programs or that suffered loss or damage
to facilities or property used to deliver government-like services. This program is largely funded by FEMA with both local and state
matching contributions required. PA is detailed on the FEMA website: https://www.fema.gov/public-assistance-local-state-tribal-and-
non-profit.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
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Department of Homeland
Security Grant Program
Description: The Homeland Security Grant Program (HSGP) plays an important role in the implementation of the National Preparedness System by
supporting the building, sustainment, and delivery of core capabilities essential to achieving the National Preparedness Goal of a
secure and resilient nation. In FY 2019, the total amount of funds available under HSGP was $1.095 billion.
HSGP is comprised of three interconnected grant programs including the State Homeland Security Program, Urban Areas Security
Initiative (UASI), and the Operation Stonegarden. Together, these grant programs fund a range of preparedness activities, including
planning, organization, equipment purchase, training, exercises, and management and administration.
Additional information regarding HSGP is available on the website: https://www.fema.gov/homeland-security-grant-program.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Fire Management
Assistance Grant Program
Description: Assistance for the mitigation, management, and control of fires on publicly or privately-owned forests or grasslands that threaten such
destruction as would constitute a major disaster. Provides a 75% federal cost share and the state pays the remaining 25% for actual
cost. Information on this program is available on the website: https://www.fema.gov/fire-management-assistance-grant-program.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: Wildfire
Assistance to Firefighters
Grant Program
Description: The primary goal of the Assistance to Firefighters Grants is to enhance the safety of the public and firefighters with respect to fire-
related hazards by providing direct financial assistance to eligible fire departments, nonaffiliated Emergency Medical Services
organizations, and State Fire Training Academies. This funding is for critically needed resources to equip and train emergency
personnel to recognized standards, enhance operations efficiencies, foster interoperability, and support community resilience.
Information regarding this grant program is available on the website: https://www.fema.gov/welcome-assistance-firefighters-grant-
program.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: Wildfire
High Hazard Potential Dams
Grant Program
Description: The Rehabilitation of High Hazard Potential Dams Grant Program provides technical, planning, design, and construction assistance in
the form of grants to non-Federal governmental organizations or nonprofit organizations for rehabilitation of eligible high hazard
potential dams. Information regarding this program is available on the website: https://www.grants.gov/web/grants/view-
opportunity.html?oppId=316238.
Responsible Agency: FEMA
Provides Funding for
Mitigation:
Yes
Hazard: Flood
Small Business
Administration Loan
Description: The Small Business Administration (SBA) provides low-interest disaster loans to homeowners, renters, business of all sizes, and most
private nonprofit organizations. SBA disaster loans can be used to repair or replace the following items damaged or destroyed in a
declared disaster: real estate, personal property, machinery and equipment, and inventory and business assets.
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Homeowners could apply for up to $200,000 to replace or repair their primary residence. Renters and homeowners could borrow up to
$40,000 to replace or repair personal property-such as clothing, furniture, cars, and appliances that were damaged or destroyed in a
disaster. Physical disaster loans of up to $2 million are available to qualified businesses or most private nonprofit organizations.
Additional information regarding SBA loans is available on the SBA website: https://www.sba.gov/managing-business/running-
business/emergency-preparedness/disaster-assistance.
Responsible Agency: SBA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Community Development
Block Grant Program
Description: CDBG are federal funds intended to provide low and moderate-income households with viable communities, including decent
housing, a suitable living environment, and expanded economic opportunities. Eligible activities include community facilities and
improvements, roads and infrastructure, housing rehabilitation and preservation, development activities, public services, economic
development, and planning and administration. Public improvements could include flood and drainage improvements. In limited
instances and during the times of “urgent need” (e.g., post disaster) as defined by the CDBG National Objectives, CDBG funding
could be used to acquire a property located in a floodplain that was severely damaged by a recent flood, demolish a structure severely
damaged by an earthquake, or repair a public facility severely damaged by a hazard event. Additional information regarding CDBG is
available on the website: https://www.hudexchange.info/programs/cdbg-entitlement/.
Responsible Agency: HUD
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Federal Highway
Administration-Emergency
Relief
Description: The Federal Highway Administration (FHWA) Emergency Relief is a grant program through the U.S. Department of Transportation
(DOT) that can be used for repair or reconstruction of federal-aid highways and roads on federal lands that have suffered serious
damage as a result of a disaster. New Jersey Department of Transportation serves as the liaison between local municipalities and
FHWA.
Additional information regarding the FHWA Emergency Relief Program is available on the website:
https://www.fhwa.dot.gov/programadmin/erelief.cfm.
Responsible Agency: U.S. DOT
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Federal Transit
Administration - Emergency
Relief
Description: The Federal Transit Authority (FTA) Emergency Relief is a grant program that funds capital projects to protect, repair, reconstruct, or
replace equipment and facilities of public transportation systems. Administered by the Federal Transit Authority at the U.S. DOT and
directly allocated to Metropolitan Transit Authority (MTA) and Port Authority, this transportation-specific fund was created as an
alternative to FEMA PA. Currently, a total of $5.2 billion has been allocated to New Jersey-related entities. Additional information
regarding the FTA Emergency Relief Program is available on the website: https://www.transit.dot.gov/funding/grant-
programs/emergency-relief-program/emergency-relief-program.
Responsible Agency: U.S. DOT
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
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Disaster Housing Program Description: Emergency assistance for housing, including minor repair of home to establish livable conditions, mortgage, and rental assistance
available through the U.S. Department of Housing and Urban Development (HUD). Information on this program is available on the
website: https://www.hud.gov/program_offices/public_indian_housing/publications/dhap.
Responsible Agency: HUD
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
HOME Investment
Partnerships Program
Description: Grants to local and state government and consortia for permanent and transitional housing, (including financial support for property
acquisition and rehabilitation for low income persons). Information on this program is available on the website:
https://www.hud.gov/program_offices/comm_planning/affordablehousing/programs/home/.
Responsible Agency: HUD
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
HUD Disaster Recovery
Assistance
Description: Grants to fund gaps in available recovery assistance after disasters (including mitigation). Information on this program is available on
the website: https://www.hud.gov/info/disasterresources.
Responsible Agency: HUD
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Section 108 Loan Guarantee Description: Enables states and local governments participating in the CDBG program to obtain federally guaranteed loans for disaster-distressed
areas. Information on this program is available on the website: https://www.hudexchange.info/programs/section-108/.
Responsible Agency: HUD
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Smart Growth
Implementation Assistance
program
Description: The Smart Growth Implementation Assistance (SGIA) program through the U.S. Environmental Protection Agency (EPA) focuses on
complex or cutting-edge issues, such as stormwater management, code revision, transit-oriented development, affordable housing,
infill development, corridor planning, green building, and climate change. Applicants can submit proposals under 4 categories:
community resilience to disasters, job creation, the role of manufactured homes in sustainable neighborhood design, or medical and
social service facilities siting. Information on this program is available on the website: https://www.epa.gov/smartgrowth.
Responsible Agency: EPA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Partners for Fish and Wildlife Description: Financial and technical assistance to private landowners interested in pursuing restoration projects affecting wetlands and riparian
habitats. Information on this program is available on the website: https://www.fws.gov/partners/.
Responsible Agency: U.S. Fish and Wildlife Service
Provides Funding for
Mitigation:
Yes
Hazard: All Natural Hazards
Description: Investing in critical road, rail, transit, and port projects across the nation. Information on this program is available on the website:
https://www.transportation.gov/tags/tiger-grants.
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Capability Details
Transportation Investment
Generating Economic
Recovery (TIGER)
Responsible Agency: U.S. DOT
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Community Facilities Direct
Loan & Grant Program
Description: This program provides affordable funding to develop essential community facilities in rural areas. An essential community facility is
defined as a facility that provides an essential service to the local community for the orderly development of the community in a
primarily rural area, and does not include private, commercial, or business undertakings. Information on this program is available on
the website: https://www.rd.usda.gov/programs-services/community-facilities-direct-loan-grant-program.
Responsible Agency: USDA
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Emergency Loan Program Description: USDA’s Farm Service Agency provides emergency loans to help producers recover from production and physical losses due to
drought, flooding, other natural disasters, or quarantine. Information on this program is available on the website:
https://www.fsa.usda.gov/programs-and-services/farm-loan-programs/emergency-farm-loans/index.
Responsible Agency: USDA
Provides Funding for
Mitigation:
Yes
Hazard: All Natural Hazards
Emergency Watershed
Protection program
Description: The Emergency Watershed Protection (EWP) program provides assistance to relieve imminent hazards to life and property caused by
floods, fires, drought, windstorms, and other natural occurrences through the Natural Resources Conservation Service. Information on
this program is available on the website: https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/landscape/ewpp/.
Responsible Agency: USDA
Provides Funding for
Mitigation:
Yes
Hazard: All Natural Hazards
Financial Assistance Description: Financial assistance to help plan and implement conservation practices that address natural resource concerns or opportunities to help
save energy, improve soil, water, plant, air, animal and related resources on agricultural lands and non-industrial private forest land.
Information on this program is available on the website: https://www.nrcs.usda.gov/wps/portal/nrcs/main/national/programs/financial/.
Responsible Agency: NRCS
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Emergency Management
Performance Grants (EMPG)
Program
Description: Assist local, tribal, territorial, and state governments in enhancing and sustaining all-hazards emergency management capabilities.
Information on this program is available on the website: https://www.fema.gov/emergency-management-performance-grant-program.
Responsible Agency: U.S. DHS
Provides Funding for
Mitigation:
Yes
Hazard: All Hazards
Reimbursement for
Firefighting on Federal
Property
Description: Provides reimbursement only for direct costs and losses over and above normal operating costs. Information on this program is
available on the website: https://www.usfa.fema.gov/grants/firefighting_federal_property.html.
Responsible Agency: U.S. DHS
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Capability Details
Provides Funding for
Mitigation:
Yes
Hazard: Wildfire
Land & Water Conservation
Fund
Description: Matching grants to states and local governments for the acquisition and development of public outdoor recreation areas and facilities
(as well as funding for shared federal land acquisition and conservation strategies). Information on this program is available on the
website: https://www.nps.gov/subjects/lwcf/index.htm.
Responsible Agency: National Park Service
Provides Funding for
Mitigation:
Yes
Hazard: All Natural Hazards
State
Texas Water Development
Board Flood Funding
Description: The TWDB offers a variety of cost-effective loan and grant programs that provide for the planning, acquisition, design, and
construction of water related infrastructure and other water quality improvements
Responsible Agency: Texas Water Development Board
Provides Funding for
Mitigation:
Yes
Hazard: Flooding
Texas A&M Forest Service
Prescribed Burn Grants
Description: Texas A&M Forest Service offers grants to landowners to complete prescribed fires on private land. Each grant targets landowners in
different priority areas across the state.
Responsible Agency: Texas A&M Forest Service
Provides Funding for
Mitigation:
Yes
Hazard: Wildfire
Flood Control Dam
Infrastructure Projects -
Supplemental Funding
Description: Projects to repair and rehabilitate flood control structures across Texas will now be funded due to a $150 million appropriations bill
legislators passed this session.
Responsible Agency: Texas State Soil and Water Conservation Board
Provides Funding for
Mitigation:
Yes
Hazard: Flooding, Dam Failure
Flood Infrastructure Fund
(FIF)
Description: FIF program provides financial assistance in the form of loans and grants for flood control, flood mitigation, and drainage projects
Responsible Agency: Texas Water Development Board
Provides Funding for
Mitigation:
Yes
Hazard: Flooding
TEXAS COASTAL
MANAGEMENT PROGRAM
GRANT
Description: Funding for projects that address environmental concerns and promote economic development within the Texas coastal zone.
Responsible Agency: Texas General Land Office
Provides Funding for
Mitigation:
Yes
Hazard: Erosion and Flooding
Texas Farm and Ranch Lands
Conservation Program
(TFRLCP)
Description: Funding conserves natural resources by protecting working lands from fragmentation and development. TFRLCP maintains and
enhances the ecological and agricultural productivity of these lands through Agricultural Conservation Easements.
Responsible Agency: Texas Parks and Wildlife
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Capability Details
Provides Funding for
Mitigation:
Yes
Hazard: Flooding
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5.5 PLAN INTEGRATION
Described earlier in this section and within each annex, participating jurisdictions identified integration of hazard
risk management into their existing planning, regulatory, and operational/administrative framework
(“integration capabilities”) and intended integration promotion (integration actions). Volume II, Section 9
(Jurisdictional Annexes) provides details on how each jurisdiction integrates hazard mitigation into their existing
capabilities.
5.5.1 Integration Process
Hazard mitigation is a sustained action taken to reduce or eliminate the long-term risk to human life and property
from hazards. Integrating hazard mitigation into a community’s existing plans, policies, codes, and programs
leads to development patterns that do not increase risk from known hazards or leads to redevelopment that
reduces risk from known hazards. The Galveston County Planning Partnership was tasked with identifying how
hazard mitigation is integrated into existing planning mechanisms. Section 9 (Jurisdictional Annex es) details
how this is done for each participating municipality and the County. During this process, many municipalities
recognized the importance and benefits of incorporating hazard mitigation into future municipal planning and
regulatory processes and have added new mitigation actions to support this effort.
The Planning Partnership representatives will continue to incorporate mitigation planning as an integral
component of daily government operations. Planning Partnership representatives will continue to work with
local government officials to integrate the newly adopted hazard mitigation goals and actions into the general
operations of government and partner organizations. Further, the sample adoption resolution presented in
Appendix A (Plan Adoption) includes a resolution item stating the intent of the local governing body to
incorporate mitigation planning as an integral component of government and partner operations. By doing so,
the Planning Partnership anticipates that:
1. Hazard mitigation planning will be formally recognized as an integral part of overall planning and
emergency management efforts.
2. The Hazard Mitigation Plan, Master Plans, Emergency Management Plans, and other relevant planning
mechanisms will become mutually supportive documents that work in concert to meet the goals and
needs of County residents.
Section 7 (Plan Maintenance) provides for additional information on the implementation of the mitigation plan
through existing programs.
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SECTION 6. MITIGATION STRATEGY
6.1 INTRODUCTION
This section presents mitigation actions for Galveston County to
reduce potential exposure and losses identified as concerns in the
Risk Assessment (Section 5). The County and planning
partnership reviewed the risk assessment to identify and develop
these mitigation actions, which are presented herein.
This section includes:
• Background and Past Mitigation Accomplishments
• General Mitigation Planning Approach
• Strengths, Weaknesses, Obstacles, and Opportunities
• Review and Update of Mitigation Goals and Objectives
• Plan Integration
• Mitigation Strategy Development and Update
6.2 BACKGROUND AND PAST MITIGATION ACCOMPLISHMENTS
In accordance with DMA 2000 requirements, a discussion regarding past mitigation activities and an overview
of past efforts is provided as a foundation for understanding the mitigation goals, objectives, and activities
outlined in this HMP. The County, through previous and ongoing hazard mitigation activities, has demonstrated
that it is pro-active in protecting its physical assets and citizens against losses from natural and human-caused
hazards. Examples of previous and ongoing actions, projects and capabilities include the following:
• The County participated in the development of the 2017 Mitigation Plan and facilitated the 2022 Update,
which included the participation of all municipal governments in the County. The current planning
process represents the regulatory five-year local plan update process.
• All 11 municipalities in Galveston County participate in the National Flood Insurance Program (NFIP),
which requires the adoption of FEMA floodplain mapping and certain minimum construction standards
for building within the floodplain.
• Currently, 7 of the 11 municipalities in Galveston County are participants in NFIP Community Rating
System (CRS) program.
o Dickinson, 8
o Friendswood, 7
o Galveston (City), 6
o Jamaica Beach, 8
o Kemah, 8
o League City, 5
o Tiki Island, 7
• Many municipalities in Galveston County have adopted regulatory standards regarding land-use and
zoning that exceed minimum requirements and provide the communities with greater capability to
manage development without increasing hazard risk and vulnerability.
Hazard mitigation reduces the potential
impacts of, and costs associated with,
emergency and disaster-related events.
Mitigation actions address a range of
impacts, including impacts on the
population, property, the economy, and the
environment.
Mitigation actions can include activities
such as: revisions to land-use planning,
training and education, and structural and
nonstructural safety measures.
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• Municipalities have participated on a limited basis in available mitigation grant funding opportunities
to implement mitigation projects, including the following:
o Elevation of private properties located in riverine and coastal areas
o Mitigation reconstruction
o Stormwater management in League City – culverts, diversions, storage, and detention/retention
basins
o Generators
o The County is a recipient of a 2019 PDM grant for preparation of the 2022 Hazard Mitigation
Plan
• The County and municipalities have implemented mitigation actions to protect critical facilities and
infrastructure throughout the planning area. These actions and others were identified in the County’s
Participation in the 2017 Hazard Mitigation Plan.
• TDEM supports Galveston County communities reduce their risk and increase their resilience. They
provide a comprehensive program to support local jurisdictions as they assess the risks they face, plan
to mitigate them, and fund those plans to implement mitigation projects that reduce risk across the
County.
• In 2020, the County and local municipalities responded to and worked to mitigate the impacts of the
coronavirus pandemic through education of the public, enforcement of local and state social distancing
and masking measures, and establishment of best practices to slow the spread of Covid-19.
These past and ongoing activities have contributed to the County’s understanding of its hazard preparedness and
future mitigation activity needs, costs, and benefits. These efforts provide an ongoing foundation for the
planning partnership to use in developing this HMP update.
6.3 GENERAL MITIGATION PLANNING APPROACH
The overall approach used to update the County and local hazard mitigation strategies are based on FEMA and
State of Texas regulations and guidance regarding local mitigation plan development, including:
• DMA 2000 regulations, specifically 44 CFR 201.6 (local mitigation planning).
• FEMA Local Mitigation Planning Handbook, March 2013.
• FEMA Local Mitigation Plan Review Guide, October 1, 2011.
• FEMA Integrating Hazard Mitigation into Local Planning, March 1, 2013.
• FEMA Plan Integration: Linking Local Planning Efforts, July 2015.
• FEMA Mitigation Planning How-To Guide #3, Identifying Mitigation Actions, and Implementing
Strategies (FEMA 386-3), February 2013.
• FEMA Mitigation Ideas: A Resource for Reducing Risk to Natural Hazards, January 2013.
The mitigation strategy update approach includes the following steps that are further detailed in later subsections
of this section:
• Section 6.4 – Strengths, Weaknesses, Obstacles, and Opportunities (SWOO) exercise
• Section 6.5 – Review and update mitigation goals and objectives.
• Section 6.6 - Develop and prepare a mitigation strategy, including:
o Review of the 2017 HMP mitigation actions
o Identification of progress on previous county and local mitigation strategies
o 2022 HMP Mitigation Action Plan
o Mitigation best practices
o Mitigation strategy evaluation and prioritization; and
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o Benefit/cost review.
6.4 STRENGTHS, WEAKNESSES, OBSTACLES, AND OPPORTUNITIES
EXERCISE
A Strengths, Weakness, Obstacles and Opportunities exercise (SWOO) was completed by the planning
partnerships. Participants were asked to fill out the SWOO for each of the hazards of concern for the 2022 HMP
update. The Planning partnership was asked to begin the exercise by identifying county, local, and stakeholder
strengths to mitigate the risk and potential future impacts of the hazards. Next, the weaknesses, challenges, and
obstacles the planning area faces to reduce each hazard’s risk were identified. To conclude the discussion of
each high-ranked hazard, the meeting attendees were asked to identify potential opportunities for enhanced
mitigation. The results were compiled and presented to the planning partnership at the risk assessment
presentation. The results were also used by the participants to help identify capabilities and potential mitigation
actions. The following summarizes the general categories of potential opportunities identified during the
exercise:
• Conduct surveys and assessments to provide current conditions so existing problems can be addressed
before they become more severe.
• Standardized public information and outreach for the County and municipalities.
• Shared services throughout the County.
• The need for training for county and municipal staff.
6.5 REVIEW AND UPDATE OF MITIGATION GOALS AND OBJECTIVES
This section documents the efforts to update the guiding principles, and hazard mitigation goals and objectives
established to reduce or avoid long-term vulnerabilities to the identified hazards.
6.5.1 Goals and Objectives
According to CFR 201.6(c)(3)(i): “The hazard mitigation
strategy shall include a description of mitigation goals to
reduce or avoid long-term vulnerabilities to the identified
hazards.” Further, FEMA mitigation planning guidance
recommends establishing objectives to better tie mitigation
goals to specific mitigation strategies (e.g. projects, activities,
and initiatives).
The goals established in the 2017 Galveston County Multi-
Jurisdictional Hazard Mitigation Plan were presented to the
Steering Committee and Planning Partnership for review and
amendment throughout the planning process. This review was
made with consideration of the hazard events and losses since
the 2017 plan, the updated hazard profiles and vulnerability
assessment, and the goals and objectives established in the updated 2018 State HMP.
The Steering Committee met on December 2, 2021 to review the 2017 goals and objectives and provided input
on updated goals and objectives. These updates were presented to the Planning Partnership during the August
2021 Mitigation Strategy Workshop. As a result of these efforts, Table 6-1 presents Galveston County’s updated
FEMA defines Goals as general guidelines
that explain what should be achieved. Goals
are usually broad, long-term, policy
statements, and represent a global vision.
FEMA defines Objectives as strategies or
implementation steps to attain mitigation
goals. Unlike goals, objectives are specific
and measurable, where feasible.
FEMA defines Mitigation Actions as specific
actions that help to achieve the mitigation
goals and objectives.
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goals and objectives for the 2022 HMP update. Italicized text indicates the updates made to the goals and
objectives from the 2017 HMP.
Table 6-1. Galveston County 2022 Hazard Mitigation Plan Goals and Objectives
2022 HMP Update Goals 2022 HMP Update Objectives
Goal 1: Minimize loss of life,
injury, damage to property,
the economy, and natural
systems from natural and
human-caused hazard events
1.1: Protect the life, health, and safety of residents
1.2: Protect existing/new critical facilities and community lifelines
1.3: Enforce regulatory measures to ensure that current and new development will not put
people in harm’s way or increase threats to existing properties.
1.4: Provide backup power to critical facilities and community lifelines
1.5: Minimize impacts from all hazards
1.6: Build, enhance, and support partnerships to continuously become less vulnerable to
hazards
Goal 2: Maintain and enhance
emergency management/
mitigation capabilities
2.1: Update/develop plans, studies, and mapping for all hazards of concern for the County
2.2: Incorporate/improve hazard mitigation strategies into ordinances, plans and polices
2.3: Conduct/develop drills/training for all hazards of concern for the County
2.4: Implement and maintain the Galveston County Multi‐Jurisdictional Hazard Mitigation
Plan
2.5: Participate in programs that promote hazard mitigation strategies
2.6: Build, obtain, and maintain critical facilities, community lifelines, and equipment
Goal 3: Enhance and
Maintain public education
and awareness activities
3.1: Expand Public Outreach Campaigns for all hazards
3.2: Promote and encourage disaster preparedness planning of appropriate hazard mitigation
measures for families
Goal 4: Address long-term
vulnerabilities from high
hazard dams
4.1: Ensure dam infrastructure is routinely inspected and maintained.
4.2: Ensure Emergency Action Plans are developed and updated.
4.3: Support the identification and access to funding to repair, replace, or decommission
dams.
6.6 MITIGATION STRATEGY DEVELOPMENT AND UPDATE
As required by FEMA, the County and participating municipalities completed a comprehensive evaluation of
the mitigation strategies and actions from the 2017 HMP and reported on the status of each. Their update may
be found in each jurisdictional annex (Section 9). In addition, the County and participating municipalities were
provided the opportunity to include new strategies or actions to include in the 2022 HMP Update. New action s
were prioritized to ensure they are cost-effective, environmentally sound, and technically feasible using the
methodology outlined below.
6.6.1 Review of the 2017 HMP Mitigation Action Plan
To evaluate progress on local mitigation actions, the planning consultant met with each participant to discuss the
status of the mitigation actions identified in the 2017 plan. For each action, jurisdictions were asked to provide
the status of each action (No Progress, In Progress, Ongoing Capability, Discontinue, or Completed) and
provide review comments on each. Jurisdictions were requested to quantify the extent of progress and provide
reasons for the level of progress or why actions were being discontinued. Each jurisdictional annex in Section
9 (Jurisdictional Annexes) provides a table identifying the jurisdiction’s prior mitigation strategy, the status of
those actions and initiatives, and their disposition within their updated strategy.
Local mitigation actions identified as Complete, and those actions identified as Discontinued, were removed
from the updated strategies. Local mitigation actions identified as an Ongoing Capability were incorporated
into the capability assessment of each jurisdictional annex. Those actions identified as No Progress or In
Progress that remain a priority for the jurisdiction, have been carried forward into the updated mitigation
strategy. Actions identified as Ongoing Capabilities which are fully integrated into the normal operational and
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administrative framework of the community have been identified within the capabilities section of each annex
and removed from the updated mitigation strategy.
At the September kick-off meeting and during subsequent local-
level planning meetings (phone, email), all participating
jurisdictions were requested to identify mitigation activities
completed, ongoing, and potential/proposed. As new potential
mitigation actions, projects, or initiatives became evident during
the plan update process, including as part of the risk assessment
update and as identified through the public and stakeholder
outreach process detailed in Section 2 (Planning Process),
jurisdictions were made aware of these either through direct
communication (local meetings, email, phone), at Steering and
Planning Committee meetings, or via their draft jurisdictional
annexes.
6.6.2 Identification and Analysis of Mitigation Techniques
Concerted efforts were made to assure that municipalities develop updated mitigation strategies that included
activities and initiatives covering the range of mitigation action types described in recent FEMA planning
guidance (FEMA “Local Mitigation Planning Handbook” March 2013), specifically:
• Local Plans and Regulations - These actions include government authorities, policies or codes that
influence the way land and buildings are being developed and built.
• Structure and Infrastructure Projects - These actions involve modifying existing structures and
infrastructure to protect them from a hazard or remove them from a hazard area. This could apply to
public or private structures as well as critical facilities and infrastructure. This type of action also
involves projects to construct manmade structures to reduce the impact of hazards.
• Natural Systems Protection - These are actions that minimize damage and losses, and also preserve or
restore the functions of natural systems.
• Education and Awareness Programs - These are actions to inform and educate citizens, elected officials,
and property owners about hazards and potential ways to mitigate them. These actions may also include
participation in national programs, such as the National Flood Insurance Program and Community
Rating System, StormReady (NOAA) and Firewise (NFPA) Communities.
6.6.3 2022 HMP Mitigation Action Plan
To help support the selection of an appropriate, risk-based mitigation strategy, each annex provides a summary
of hazard vulnerabilities identified during the plan update process, either directly by municipal representatives,
through review of available county and local plans and reports, and through the hazard profiling and vulnerability
assessment process.
In December 2021, the planning partnership participated in a mitigation strategy development workshop,
supplemented by emails and phone calls between jurisdictions and the contract consultant, for all participating
jurisdictions to support the development of focused problem statements based on the impacts of natural hazards
in the county and their communities. These problem statements were intended to provide a detailed description
of the problem area, including its impacts to the municipality/jurisdiction; past damages; loss of service; etc. An
effort was made to include the street address of the property/project location, adjacent streets, water bodies, and
well-known structures as well as a brief description of existing conditions (topography, terrain, hydrology) of
Throughout the planning process, the
planning consultant worked directly with
each community (phone, email) to assist with
the development and update of their annex
and include mitigation strategies, focusing on
identifying well-defined, implementable
projects with a careful consideration of
benefits (risk reduction, losses avoided),
costs, and possible funding sources
(including mitigation grant programs).
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the site. These problem statements formed a bridge between the hazard risk assessment which quantifies impacts
to each community with the development of actionable mitigation strategies.
As discussed within the hazard profiles in Section 4.3 (Risk Assessment), the long-term effects of climate change
are anticipated to exacerbate the impacts of weather-related hazards including flood, hurricanes and tropical
storm, nor’easter, severe weather, severe winter weather and wildfire. By way of addressing these climate
change-sensitive hazards within their local mitigation strategies and integration actions, communities are
working to evaluate and recognize these long-term implications and potential impacts, and to incorporate in
planning and capital improvement updates.
A strong effort has been made to better focus local mitigation
strategies to clearly defined, readily implementable projects and
initiatives that meet the definition or characteristics of
mitigation. Broadly defined mitigation actions were eliminated
from the updated strategy unless accompanied by discrete
actions, projects, or initiatives. Certain continuous or ongoing
strategies that represent programs that are fully integrated into
the normal operational and administrative framework of the
community have been identified within the capabilities section
of each annex and removed from the updated mitigation strategy.
Overall, a comprehensive range of specific mitigation initiatives
were considered by each plan participant to pursue in the future
to reduce the effects of hazards. Some of these initiatives may be
previous actions carried forward for this plan update. These initiatives are dependent upon available funding
(grants and local match availability) and may be modified or omitted at any time based on the occurrence of new
hazard events and changes in municipal priorities.
Throughout the course of the plan update process, additional regional and county-level mitigation actions were
identified by the following processes:
• Review of the results and findings of the updated risk assessment.
• Review of available regional and county plans reports and studies.
• Direct input from county departments and other county and regional agencies
• Input received through the public and stakeholder outreach process.
6.6.4 Mitigation Best Practices
Catalogs of hazard mitigation best practices were developed that present a broad range of alternatives to be
considered for use in Galveston County, in compliance with 44 CFR Section 201.6(c)(3)(ii). One catalog was
developed for each natural hazard of concern evaluated in this plan; referred to as Appendix F (Mitigation
Strategy Supplementary Data). The catalogs present alternatives that are categorized in two ways:
• By whom would have responsibility for implementation:
o Individuals – personal scale
o Businesses – corporate scale
o Government – government scale
• By what each of the alternatives would do:
o Manipulate the hazard
o Reduce exposure to the hazard
To assist with the development of
mitigation actions, municipalities were
provided with the following:
•2022 HMP goals and objectives
•2017 HMP mitigation strategy
•Risk assessment results
•Outcome of the SWOO
•Mitigation catalog
•Stakeholder and public input (e.g.
citizen and stakeholder survey results)
•FEMA resources
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o Reduce vulnerability to the hazard
o Build local capacity to respond to or be prepared for the hazard
The alternatives presented include actions that will mitigate current risk from hazards and actions that will help
reduce risk from changes in the impacts of these hazards resulting from climate change. Hazard mitigation
actions recommended in this plan were selected from among the alternatives presented in the catalog, as well as
other resources made available to all jurisdictions (i.e., FEMA’s Mitigation Ideas). The catalog provides a
baseline of mitigation alternatives that are backed by a planning process, are consistent with the established goals
and objectives, and are within the capabilities of the planning partners to implement. Some of these actions may
not be feasible based on the selection criteria identified for this plan. The purpose of the catalog was to provide
a list of what could be considered to reduce risk from natural hazards within the planning area. Actions in the
catalog that are not included for the partnership’s action plan were not selected for one or more of the following
reasons:
• The action is not feasible
• The action is already being implemented
• There is an apparently more cost-effective alternative
• The action does not have public or political support.
6.6.5 Mitigation Strategy Evaluation and Prioritization
Section 201.c.3.iii of 44 CFR requires an action plan describing how the actions identified will be prioritized.
Recent FEMA planning guidance (March 2013) identifies a modified STAPLEE (Social, Technical,
Administrative, Political, Legal, Economic, and Environmental) mitigation action evaluation methodology that
uses a set of 10 evaluation criteria suited to the purposes of hazard mitigation strategy evaluation. This method
provides a systematic approach that considers the opportunities and constraints of implementing a particular
mitigation action.
Based on this guidance, the Steering Committee has adopted and applied an action evaluation and prioritization
methodology which includes an expanded set of 14 criteria to include the consideration of cost-effectiveness,
availability of funding, anticipated timeline, and if the action addresses multiple hazards.
The 14 evaluation/prioritization criteria used in the 2022 update process are:
1) Life Safety – How effective will the action be at protecting lives and preventing injuries?
2) Property Protection – How significant will the action be at eliminating or reducing damage to
structures and infrastructure?
3) Cost-Effectiveness – Are the costs to implement the project or initiative commensurate with the benefits
achieved?
4) Technical – Is the mitigation action technically feasible? Is it a long-term solution? Eliminate actions
that, from a technical standpoint, will not meet the goals.
5) Political – Is there overall public support for the mitigation action? Is there the political will to support
it?
6) Legal – Does the municipality have the authority to implement the action?
7) Fiscal – Can the project be funded under existing program budgets (i.e., is this initiative currently
budgeted for)? Or would it require a new budget authorization or funding from another source such as
grants?
8) Environmental – What are the potential environmental impacts of the action? Will it comply with
environmental regulations?
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9) Social – Will the proposed action adversely affect one segment of the population? Will the action disrupt
established neighborhoods, break up voting districts, or cause the relocation of lower income people?
10) Administrative – Does the jurisdiction have the personnel and administrative capabilities to implement
the action and maintain it or will outside help be necessary?
11) Multi-hazard – Does the action reduce the risk to multiple hazards?
12) Timeline – Can the action be completed in less than 5 years (within our planning horizon)?
13) Local Champion – Is there a strong advocate for the action or project among the jurisdiction’s staff,
governing body, or committees that will support the action’s implementation?
14) Other Local Objectives – Does the action advance other local objectives, such as capital
improvements, economic development, environmental quality, or open space preservation? Does it
support the policies of other plans and programs?
Specifically, for each mitigation action, the jurisdictions were asked to assign a numeric rank (-1, 0, or 1) for
each of the 14 evaluation criteria, defined as follows:
• 1 = Highly effective or feasible
• 0 = Neutral
• -1 = Ineffective or not feasible
Further, jurisdictions were asked to provide a summary of the rationale behind the numeric rankings assi gned,
as applicable. The numerical results were totaled to assist each jurisdiction in selecting mitigation actions for the
updated plan.
As step one in the prioritization process, actions that had a numerical value between 0 and 4 were initially
prioritized as low; actions with numerical values between 5 and 9 were initially categorized as me dium; and
actions with numerical values between 10 and 14 were initially categorized as high. As step two, jurisdictions
were then asked to consider the benefits and costs, as well as the desired timeline for implementation and project
completion timeline when finalizing each action’s priority as high/medium/low. These attributes are included
in the mitigation strategy table and for FEMA-eligible projects in the mitigation worksheets (Section 9 –
Jurisdictional Annexes).
For the plan update there has been an effort to develop more clearly defined and action-oriented mitigation
strategies. These local strategies include projects and initiatives that are seen by the community as the most
effective approaches to advance their local mitigation goals and objectives within their capabilities. In addition,
each jurisdiction was asked to develop problem statements. With this process, participating jurisdictions were
able to develop action-oriented and achievable mitigation strategies.
6.6.6 Benefit/Cost Review
Section 201.6.c.3iii of 44CFR requires the prioritization of the action plan to emphasize the extent to which
benefits are maximized according to a cost/benefit review of the proposed projects and their associated costs.
Stated otherwise, cost-effectiveness is one of the criteria that must be applied during the evaluation and
prioritization of all actions comprising the overall mitigation strategy.
The benefit/cost review applied in for the evaluation and prioritization of projects and initiatives in this HMP
update process was qualitative; that is, it does not include the level of detail required by FEMA for project grant
eligibility under the Hazard Mitigation Grant Program (HMGP), Flood Mitigation Assistance (FMA) and Pre-
Disaster Mitigation (PDM) grant programs. For all actions identified in the local strategies, jurisdictions have
identified both the costs and benefits associated with project, action, or initiative.
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Galveston County, TX | Hazard Mitigation Plan 6-9
2022 Update
Costs are the total cost for the action or project, and may include administrative costs, construction costs
(including engineering, design and permitting), and maintenance costs.
Benefits are the savings from losses avoided attributed to the implementation of the project, and may include
life-safety, structure and infrastructure damages, loss of service or function, and economic and environmental
damage and losses.
When possible, jurisdictions were asked to identify the actual or estimated dollar value for project costs and
associated benefits. Having defined costs and benefits allows a direct comparison of benefits versus costs, and
a quantitative evaluation of project cost-effectiveness. Often, however, numerical costs and/or benefits have not
been identified or may be impossible to quantitatively assess.
For the purposes of this planning process, jurisdictions were tasked with evaluating project cost-effectiveness
with both costs and benefits assigned to “High”, “Medium” and “Low” ratings. Where quantitative estimates of
costs and benefits were available, ratings/ranges were defined as:
• Low = < $10,000
• Medium = $10,000 to $100,000
• High = > $100,000
Where quantitative estimates of costs and/or benefits were not available, qualitative ratings using the following
definitions were used:
Table 6-2. Qualitative Cost and Benefit Ratings
Costs
High Existing funding levels are not adequate to cover the costs of the proposed project, and implementation
would require an increase in revenue through an alternative source (e.g., bonds, grants, and fee increases).
Medium The project could be implemented with existing funding but would require a re-apportionment of the budget
or a budget amendment, or the cost of the project would have to be spread over multiple years.
Low The project could be funded under the existing budget. The project is part of or can be part of an existing,
ongoing program.
Benefits
High Project will have an immediate impact on the reduction of risk exposure to life and property.
Medium Project will have a long-term impact on the reduction of risk exposure to life and property or will provide an
immediate reduction in the risk exposure to property.
Low Long-term benefits of the project are difficult to quantify in the short term.
Using this approach, projects with positive benefit versus cost ratios (such as high over high, high over medium,
medium over low, etc.) are considered cost-beneficial and are prioritized accordingly. For some of the Galveston
County initiatives identified, the planning partnership may seek financial assistance under FEMA’s HMGP or
Hazard Mitigation Assistance (HMA) programs. These programs require detailed benefit/cost analysis as part
of the application process. These analyses will be performed when funding applications are prepared, using the
FEMA BCA model process. The planning partnership is committed to implementing mitigation strategies with
benefits that exceed costs. For projects not seeking financial assistance from grant programs that require this
sort of analysis, the planning partnership reserves the right to define “benefits” according to parameters that meet
its needs and the goals and objectives of this HMP.
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Galveston County, TX | Hazard Mitigation Plan 7-10
2022 Update
SECTION 7. PLAN MAINTENANCE
This section details the formal process that will ensure that the HMP remains an active and relevant document
and that the Planning Partnership maintains their eligibility for applicable funding sources. The plan maintenance
process includes a schedule for monitoring and evaluating the plan annually and producing an updated plan every
five years. In addition, this section describes how public participation will be integrated throughout the plan
maintenance and implementation process. It explains how the mitigation strategies outlined in this plan update
will be incorporated into existing planning mechanisms and programs, such as comprehensive land use planning
processes, capital improvement planning, and building code enforcement and implementation. The plan’s format
allows sections to be reviewed and updated when new data become available, resulting in a plan that will remain
current and relevant
The plan maintenance matrix shown in Table 7-1 provides a synopsis of responsibilities for plan monitoring,
evaluation, and update, which are discussed in further detail in the sections below.
Table 7-1. Plan Maintenance Matrix
Task Approach Timeline Lead Responsibility
Support
Responsibility
Monitoring Preparation of status updates
and action implementation
tracking as part of submission
for Annual Progress Report.
Meet annually or upon
major update to
comprehensive plan or
major disaster
declaration
Jurisdictional points of
contact identified in
Section 8 (Planning
Partnership) and
Section 9
(Jurisdictional
Annexes)
Jurisdictional
implementation lead
identified in Section 8
(Planning
Partnership) and
Section 9
(Jurisdictional
Annexes)
Integration In order for integration of
mitigation principles action to
become an organic part of the
ongoing county and municipal
activities, the County will
incorporate the distribution of
the safe growth worksheet for
annual review and update by
all participating jurisdictions.
September each year
with interim email
reminders to address
integration in county
and municipal
activities.
HMP Coordinator and
jurisdictional points of
contact identified in
Section 8 (Planning
Partnership) and
Section 9
(Jurisdictional
Annexes)
HMP Coordinator
Evaluation Review the status of previous
actions as submitted by the
monitoring task lead and
support to assess the
effectiveness of the plan;
compile and finalize the
Annual Progress Report
Finalized progress
report completed by
October 14 of each
year
Planning Partnership;
Plan Maintenance
element
Jurisdictional points
of contacts identified
in Section 9
(Jurisdictional
Annexes)
Update Reconvene the planning
partners, at a minimum, every
5 years to guide a
comprehensive update to
review and revise the plan.
Every 5 years or upon
major update to Master
Plan or major disaster
Galveston County
HMP Coordinator
Jurisdictional points
of contacts identified
in Section 9
(Jurisdictional
Annexes)
7.1 MONITORING, EVALUATING AND UPDATING THE PLAN
The procedures for monitoring, evaluating, and updating the plan are provided below.
The HMP Coordinator is assigned to manage the maintenance and update of the plan during its performance
period. The HMP Coordinator will chair the Planning Partnership and be the prime point of contact for questions
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2022 Update
regarding the plan and its implementation as well as to coordinate incorporation of additional information into
the plan.
The Planning Partnership shall fulfill the monitoring, evaluation and updating responsibilities identified in this
section which is comprised of a representative from each participating jurisdiction. Each jurisdiction is expected
to maintain a representative on the Planning Partnership throughout the plan performance period (five years from
the date of plan adoption). As of the date of this plan, primary and secondary mitigation planning representatives
(points-of-contact) are identified in each jurisdictional annex in Section 9 (Jurisdictional Annexes). Each
jurisdiction will participate in an annual meeting to update the status of their action plan and incorporate
information, ideas, and strategies into their individual action plans.
Regarding the composition of the committee, it is recognized that individual commitments change over time,
and it shall be the responsibility of each jurisdiction and its representatives to inform the HMP Coordinator of
any changes in representation. The HMP Coordinator will strive to keep the committee makeup as a uniform
representation of planning partners and stakeholders within the planning area.
Currently, the Galveston County HMP Coordinator is designated as:
Laura M. Norman, Deputy Emergency Management Coordinator
Galveston County Office of Emergency Management
281-309-5013 | laura.norman@co.galveston.tx.us
7.1.1 Monitoring
The Planning Partnership will be responsible for monitoring progress on, and evaluating the effectiveness of, the
plan, and documenting annual progress. Each year, beginning one year after plan development, the Galveston
County and local Planning Partnership representatives will collect and process information from the departments,
agencies and organizations involved in implementing mitigation projects or activities identified in their
jurisdictional annexes (Section 9) of this plan, by contacting persons responsible for initiating and/or overseeing
the mitigation projects.
In the first year of the performance period, this will be accomplished by utilizing an online performance progress
reporting system, the BAToolSM which will enable municipal and county representatives to directly access
mitigation initiatives to easily update the status of each project, document successes or obstacles to
implementation, add or delete projects to maintain mitigation project implementation. It is anticipated that all
participating partners will be prompted by the tool to update progress annually, providing an incentive for
participants to refresh their mitigation strategies and to continue implementation of projects. It is expected that
this reporting system will support the submittal of an increased number of project grant fund applications due to
the functionality of the system which facilitates the sorting and prioritization of projects.
In addition to progress on the implementation of mitigation actions, including efforts to obtain outside funding;
and obstacles or impediments to implementation of actions, the information that Planning Partnership
representatives shall be expected to document, as needed and appropriate include:
• Any grant applications filed on behalf of the participating jurisdictions,
• Hazard events and losses occurring in their jurisdiction,
• Additional mitigation actions believed to be appropriate and feasible,
• Public and stakeholder input, and
• Plan monitoring for two years 2 through 4 of the plan performance period will be similarly addressed
via the BAToolSM or manually.
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2022 Update
7.1.2 Integration Process of the HMP into Municipal Planning Mechanisms
Hazard mitigation is sustained action taken to reduce or eliminate the long-term risk to human life and property
from natural hazards. Integrating hazard mitigation into a community’s existing plans, policies , codes, and
programs leads to development patterns that do not increase risk from known hazards or leads to redevelopment
that reduces risk from known hazards. The Galveston County HMP Planning Partnership was tasked with
identifying how hazard mitigation is integrated into existing planning mechanisms. Refer to Section 9
(Jurisdictional Annexes) for how this is done for each participating municipality. Durin g this process, many
municipalities recognized the importance and benefits of incorporating hazard mitigation into future municipal
planning and regulatory processes.
The Planning Partnership representatives will incorporate mitigation planning as an integral component of daily
government operations. They will work with local government officials to integrate the newly adopted hazard
mitigation goals and actions into the general operations of government and partner organizations. Further, the
sample adoption resolution (Appendix A) includes a resolution item stating the intent of the local governing
body to incorporate mitigation planning as an integral component of government and partner operations. By
doing so, the Planning Partnership anticipates that:
1. Hazard mitigation planning will be formally recognized as an integral part of overall planning and
emergency management efforts.
2. The Hazard Mitigation Plan, Comprehensive Plans, Emergency Management/Operations Plans and
other relevant planning mechanisms will become mutually supportive documents that work in concert
to meet the goals and needs of County residents.
During the HMP annual review process, each participating municipality will be asked to document how they are
utilizing and incorporating the Galveston County HMP 2022 update into their day-to-day operations and
planning and regulatory processes. Additionally, the County will identify additional policies, programs,
practices, and procedures that could be modified to accommodate hazard mitigation actions and include these
findings and recommendations in the Annual HMP Progress Report. The following checklist was adapted from
FEMA’s Local Mitigation Handbook (2013), Appendix A, Worksheet 4.2. This checklist will help a community
analyze how hazard mitigation is integrated into local plans, ordinances, regulations, ordinances, and policies.
By completing the checklist, it will help the County identify areas that integrate hazard mitigation currently and
where to make improvements and reduce vulnerability to future development. In this manner, the integration of
mitigation into municipal activities will evolve into an ongoing culture within the County.
Table 7-2. Safe Growth Check List
Planning Mechanisms
Do you Do
This? Notes:
How is it being done or how will this be utilized
in the future? Yes No
Operating, Municipal and Capital Improvement Program Budgets
• When constructing upcoming budgets, hazard
mitigation actions will be funded as budget
allows. Construction projects will be evaluated
to see if they meet the hazard mitigation goals.
• Annually, during adoption process, the
municipality will review mitigation actions
when allocating funding.
• Do budgets limit expenditures on projects that
would encourage development in areas
vulnerable to natural hazards?
• Do infrastructure policies limit extension of
existing facilities and services that would
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2022 Update
Planning Mechanisms
Do you Do
This? Notes:
How is it being done or how will this be utilized
in the future? Yes No
encourage development in areas vulnerable to
natural hazards?
• Do budgets provide funding for hazard
mitigation projects identified in the County
HMP?
Human Resource Manual
• Do any job descriptions specifically include
identifying and/or implementing mitigation
projects/actions or other efforts to reduce
natural hazard risk?
Building and Zoning Ordinances
• Prior to, zoning changes, or development
permitting, the municipality will review the
hazard mitigation plan and other hazard
analyses to ensure consistent and compatible
land use.
• Does the zoning ordinance discourage
development or redevelopment within natural
areas including wetlands, floodways, and
floodplains?
• Does it contain natural overlay zones that set
conditions
• Does the ordinance require developers to take
additional actions to mitigate natural hazard
risk?
• Do rezoning procedures recognize natural
hazard areas as limits on zoning changes that
allow greater intensity or density of use?
• Do the ordinances prohibit development
within, of filling of, wetlands, floodways, and
floodplains?
Subdivision Regulations
• Do the subdivision regulations restrict the
subdivision of land within or adjacent to
natural hazard areas?
• Do the subdivision regulations restrict the
subdivision of land within or adjacent to
natural hazard areas?
• Do the regulations provide for conservation
subdivisions or cluster subdivisions in order to
conserve environmental resources?
• Do the regulations allow density transfers
where hazard areas exist?
Comprehensive Plan
• Are the goals and policies of the plan related to
those of the County HMP?
• Does the future land use map clearly identify
natural hazard areas?
• Do the land use policies discourage
development or redevelopment with natural
hazard areas?
• Does the plan provide adequate space for
expected future growth in areas located outside
natural hazard areas?
Land Use
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2022 Update
Planning Mechanisms
Do you Do
This? Notes:
How is it being done or how will this be utilized
in the future? Yes No
• Does the future land use map clearly identify
natural hazard areas?
• Do the land use policies discourage
development or redevelopment with natural
hazard areas?
• Does the plan provide adequate space for
expected future growth in areas located outside
natural hazard areas?
Transportation Plan
• Does the transportation plan limit access to
hazard areas?
• Is transportation policy used to guide growth
to safe locations?
• Are transportation systems designed to
function under disaster conditions (e.g.
evacuation)?
Environmental Management
• Are environmental systems that protect
development from hazards identified and
mapped?
• Do environmental policies maintain and
restore protective ecosystems?
• Do environmental policies provide incentives
to development that is located outside
protective ecosystems?
Grant Applications
• Data and maps will be used as supporting
documentation in grant applications.
Municipal Ordinances
• When updating municipal ordinances, hazard
mitigation will be a priority
Economic Development
• Local economic development group will take
into account information regarding identified
hazard areas when assisting new businesses in
finding a location.
Public Education and Outreach
• Does the municipality have any public
outreach mechanisms / programs in place to
inform citizens on natural hazards, risk, and
ways to protect themselves during such
events?
7.1.3 Evaluating
The evaluation of the mitigation plan is an assessment of whether the planning process and actions have been
effective, if the HMP goals are being achieved, and whether changes are needed. The HMP will be evaluated on
an annual basis to determine the effectiveness of the programs, and to reflect changes that could affect mitigation
priorities or available funding.
The status of the HMP will be discussed and documented at an annual plan review meeting of the Planning
Partnership, to be held either in person or via teleconference approximately one year from the date of local
adoption of this update, and successively thereafter. At least two weeks before the annual plan review meeting,
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2022 Update
the Galveston County HMP Coordinator will advise Planning Partnership members of the meeting date, agenda,
and expectations of the members.
The Galveston County HMP Coordinator will be responsible for calling and coordinating the annual plan review
meeting and Soliciting input regarding progress toward meeting plan goals and objectives. These evaluations
will assess whether:
• Goals and objectives address current and expected conditions.
• The nature or magnitude of the risks has changed.
• Current resources are appropriate for implementing the HMP and if different or additional resources are
now available.
• Actions were cost effective.
• Schedules and budgets are feasible.
• Implementation problems, such as technical, political, legal or coordination issues with other agencies
are presents.
• Outcomes have occurred as expected.
• Changes in County resources impacted plan implementation (e.g., funding, personnel, and equipment)
• New agencies/departments/staff should be included, including other local governments as defined under
44 CFR 201.6.
Specifically, the Planning Partnership will review the mitigation goals, objectives, and activities using
performance-based indicators, including:
• New agencies/departments
• Project completion
• Under/overspending
• Achievement of the goals and objectives
• Resource allocation
• Timeframes
• Budgets
• Lead/support agency commitment
• Resources
• Feasibility
Finally, the Planning Partnership will evaluate how other programs and policies have conflicted or augmented
planned or implemented measures, and shall identify policies, programs, practices, and procedures that could be
modified to accommodate hazard mitigation actions (“Implementation of Mitigation Plan through Existing
Programs” subsection later in this section discusses this process). Other programs and policies can include those
that address:
• Economic development
• Environmental preservation
• Historic preservation
• Redevelopment
• Health and/or safety
• Recreation
• Land use/zoning
• Public education and outreach
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2022 Update
• Transportation
The Planning Partnership should refer to the evaluation forms, Worksheets #2 and #4 in the FEMA 386 -4
guidance document, to assist in the evaluation process (see Appendix F – Plan Maintenance). Further, the
Planning Partnership should refer to any process and plan review deliverables developed by the County as a part
of the plan review processes established for prior or existing local HMPs within the County.
The Galveston County HMP Coordinator shall be responsible for preparing an Annual HMP Progress Report
for each year of the performance period, based on the information provided by the local Planning Partnership
members, information presented at the annual Planning Partnership meeting, and other information as
appropriate and relevant. These annual reports will provide data for the five-year update of this HMP and will
assist in pinpointing any implementation challenges. By monitoring the implementation of the HMP on an annual
basis, the Planning Partnership will be able to assess which projects are completed, which are no longer feasible,
and what projects should require additional funding.
The Annual HMP Progress Report shall be posted on the Galveston County’s website to keep the public
appraised of the plan’s implementation (located at GCOEM.org). Additionally, the website provides details on
the HMP update planning process. As a community in the CRS program, Galveston County can use this report
to meet annual CRS recertification requirements. To meet this recertification timeline, the Planning Partnership
will strive to complete the review process and prepare an Annual HMP Progress Report by October 14th of each
year.
The HMP will also be evaluated and revised following any major disasters, to determine if the recommended
actions remain relevant and appropriate. The risk assessment will also be revisited to see if any changes are
necessary based on the pattern of disaster damages or if data listed in the Section 4.3 (Hazard Profiles) of this
plan has been collected to facilitate the risk assessment. This is an opportunity to increase the community’s
disaster resistance and build a better and stronger community.
7.1.4 Updating
To facilitate the update process, the Galveston County HMP Coordinator, with support of the Planning
Partnership, shall use the second annual meeting to develop and commence the implementation of a detailed
plan update program. The Galveston County HMP Coordinator shall invite representatives from TDEM to this
meeting to provide guidance on plan update procedures. This program shall, at a minimum, establish who shall
be responsible for managing and completing the plan update effort, what needs to be included in the updated
plan, and a detailed timeline with milestones to assure that the update is completed according to regulatory
requirements.
At this meeting, the Planning Partnership shall determine what resources will be needed to complete the update.
The Galveston County HMP Coordinator shall be responsible for assuring that needed resources are secured.
Following each five-year update of the mitigation plan, the updated plan will be distributed for public comment.
After all comments are addressed, the HMP will be revised and distributed to all planning group members and
the State of Texas State Hazard Mitigation Officer.
7.1.5 Grant Monitoring and Coordination
Galveston County recognizes the importance of having an annual coordination period that helps each planning
partner become aware of upcoming mitigation grant opportunities and identifies multi-jurisdiction projects to
pursue. Grant monitoring will be the responsibility of each municipal partner as part of their annual progress
reporting. The Galveston County HMP Coordinator will keep the planning partners apprised of FEMA Hazard
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2022 Update
Mitigation Assistance grant openings and assist in developing letters of intent for grant opportunities when
practicable.
Galveston County intends to be a resource to the planning partnership in the support of project grant writing and
development. The degree of this support will depend on the level of assistance requested by the partnership
during open windows for grant applications. As part of grant monitoring and coordination, Galveston County
intends to provide the following:
• Notification to planning partners about impending grant opportunities.
• A current list of eligible, jurisdiction-specific projects for funding pursuit consideration.
• Notification about mitigation priorities for the fiscal year to assist the planning partners in the selection
of appropriate projects.
Grant monitoring and coordination will be integrated into the annual progress report or as needed based on the
availability of non-HMA or post-disaster funding opportunities
7.2 IMPLEMENTATION OF MITIGATION PLAN THROUGH EXISTING
PROGRAMS
Effective mitigation is achieved when hazard awareness and risk management approaches and strategies become
an integral part of public activities and decision-making. Within the County there are many existing plans and
programs that support hazard risk management, and thus it is critical that this hazard mitigation plan integrate
and coordinate with, and complement, those existing plans, and programs.
Section 5 (Capability Assessment) provides a summary and description of the existing plans, programs, and
regulatory mechanisms at all levels of government (federal, state, county and local) that support hazard
mitigation within the County. Within each jurisdictional annex in Section 9 (Jurisdictional Annexes), the County
and each participating jurisdiction identified how each capability reduces risk and how they are integrating
hazard risk management into their existing planning, regulatory, and operational/administrative framework. If
they are currently not showing this, they indicate how they intend to promote this integration.
It is the intention of Planning Partnership representatives to continue to incorporate mitigation planning as an
integral component of daily government operations. The Planning Partnership representatives will work with
local government officials to integrate the newly adopted hazard mitigation goals and actions into the general
operations of government and partner organizations. Further, the sample adoption resolution (Appendix A
[Adoption Resolutions]) includes a resolution item stating the intent of the local governing body to incorporate
mitigation planning as an integral component of government and partner operations. By doing so, the Steering
Committee anticipates that:
• Hazard mitigation planning will be formally recognized as an integral part of overall emergency
management efforts.
• The Hazard Mitigation Plan, Master Plans, Emergency Operations Plans and other relevant planning
mechanisms will become mutually supportive documents that work in concert to meet the goals and
needs of county residents.
Other planning processes and programs to be coordinated with the recommendations of the hazard mitigation
plan include the following:
• Emergency operations and response plans.
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2022 Update
• Training and exercise of emergency response plans.
• Debris management plans.
• Recovery plans.
• Capital improvement programs.
• Municipal codes.
• Community design guidelines.
• Water-efficient landscape design guidelines.
• Stormwater management programs.
• Water system vulnerability assessments.
• Community Wildfire Protection Plans.
• Comprehensive Flood Hazard Management Plans.
• Resiliency plans.
• Community Development Block Grant-Disaster Recovery action plans; and
• Public information/education plans.
Some action items do not need to be implemented through regulation. Instead, these items can be implemented
through the creation of new educational programs, continued interagency coordination, or improved public
participation.
During the annual plan evaluation process, the Planning Partnership representatives will identify additional
policies, programs, practices, and procedures that could be modified to accommodate hazard mitigation actions
and include these findings and recommendations in the Annual HMP Progress Report. See Table 7-3 for
integration opportunities individual jurisdictions will utilize to incorporate the information, strategies, and
actions of this HMP into their existing plans.
Table 7-3. Integration of the HMP into Other Planning Mechanisms, By Jurisdiction
Jurisdiction Plan or Program
Last Update (if
known) How will this HMP be incorporated in the plan?
Galveston County Disaster Debris
Management Plan
Use hazard mapping to determine potentially large
areas with debris after natural disasters.
Galveston County
Floodplain
Regulations
August 2019 Incorporate flood risk assessment and hazard mapping
in regulations.
Galveston County
Dune Protection and
Beach Access Plan
September 2006 Incorporate coastal erosion, flood, tsunami and
hurricane/tropical storm risk assessments and hazard
mapping in future plan updates.
Galveston County
Agricultural Plan
Incorporate flood, drought, hail, and severe winter
storm risk assessments and available hazard mapping
in future plan updates.
Galveston County
Emergency
Management Plan
2017 Use risk assessments, hazard mapping, and mitigation
initiatives to develop plan updates.
Continuity of
Operations Plan
Use risk assessments, hazard mapping, and mitigation
initiatives to develop plan updates.
Galveston County
Health Plan, Annex H
Incorporated pandemic risk assessment and actions
into future plan updates.
Bayou Vista (C) Capital Improvement
Plan
2021-2022 City
Budget
Include applicable mitigation initiatives in annual CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
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2022 Update
Jurisdiction Plan or Program
Last Update (if
known) How will this HMP be incorporated in the plan?
Emergency
Management Plan
Use risk assessments, hazard mapping, and mitigation
initiatives to develop plan updates.
Clear Lake Shores (C) Clear Lake Shores
Strategic Plan
5-year (2019-
2024)
Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Flood Damage
Prevention (Chapter
38 of the City Code)
September 2021 Incorporate flood risk assessment and hazard mapping
in future code revisions. Seek to acquire high hazard
areas for public open space.
Stormwater Ordinance Incorporate flood risk assessment and hazard mapping
in future revisions.
Open Space
Ordinance
Incorporate flood and wildfire risk assessment and
hazard mapping in future revisions.
Town Center Master
Plan
March 2009 Incorporate flood and erosion risk assessments and
hazard mapping in future plan updates.
Town Center Overlay February 2010 Incorporate flood, erosion, and pandemic risk
assessments and available hazard mapping in future
updates.
Emergency
Management
Ordinance
August 2012 Use risk assessments, hazard mapping, and mitigation
initiatives in future revisions.
Windstorm Protection
Program
Incorporate thunderstorm wind, tornado, and
hurricane/tropical storm risk assessments and hazard
mapping in future program updates.
Dickinson (C) Comprehensive
Community Plan
2015-2030
September 2016 Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Capital Improvement
Plan
November 2021 Include applicable mitigation initiatives in annual CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
Flood Damage
Prevention and
Protection Ordinance
Incorporate flood risk assessment and hazard mapping
in future revisions. Seek to acquire high hazard areas
for public open space.
Stormwater
Management Plan
Incorporate flood risk assessment and hazard mapping
in future plan revisions.
City of Dickinson
Basic Plan
2020 Use risk assessments, hazard mapping, and mitigation
initiatives to develop plan updates.
Friendswood (C) Comprehensive Plan July 1998;
Future Land Use
Map 2008
Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Capital Improvement
Plan 2017-2020
5-year plan Include applicable mitigation initiatives in CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
Disaster Debris
Management Plan
2014 Use hazard mapping to determine potentially large
areas with debris after natural disasters.
City of Friendswood
Flood Vulnerability
and Mitigation Study
April 2019 Incorporate flood and hurricane/tropical storm risk
assessments and hazard mapping in future revisions.
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Jurisdiction Plan or Program
Last Update (if
known) How will this HMP be incorporated in the plan?
Master Drainage Plan 2018 Incorporate flood risk assessment and hazard mapping
in future revisions.
Transportation Plan 2018 In future updates, use hazard mapping to determine
potential evacuation routes before and after natural
disaster events. Use transportation planning to guide
growth to safer areas.
Downtown District
Improvement Plan
2017 Incorporate risk assessments and hazard mapping in
future revisions.
Civil Emergency
Management
Ordinance
Use risk assessments, hazard mapping, and mitigation
initiatives in future revisions.
Continuity of
Operations Plan
2014 Use risk assessments, hazard mapping, and mitigation
initiatives to develop plan updates.
Hitchcock (C) Comprehensive Plan
2020-2040
Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Capital Improvement
Plan (5-year plan)
2022 Include applicable mitigation initiatives in CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
Disaster Debris
Management Plan
Use hazard mapping to determine potentially large
areas with debris after natural disasters.
Floodplain SOP Incorporate flood risk assessment and hazard mapping
in future code revisions. Protect critical infrastructure
from flooding.
Stormwater
Management Program
– Structural Control
Guideline
Incorporate flood risk assessment and hazard mapping
in future guideline revisions.
Hitchcock Emergency
Response Plan
Use risk assessments, hazard mapping, and mitigation
initiatives to develop plan updates.
Jamaica Beach (C) Comprehensive Plan April 2017 Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Stormwater
Management
Ordinance
December 1993 Incorporate flood risk assessment and hazard mapping
in future revisions.
Shoreline
Management
Ordinance
December 1993 Incorporate flood and erosion risk assessments and
hazard mapping in future revisions. Seek to acquire
high hazard areas for public open space.
Emergency
Management
Ordinance
March 1994 Use risk assessments, hazard mapping, and mitigation
initiatives in future revisions.
Kemah (C) Strategic Plan, 2009-
2013
Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Capital Projects 2022 Include applicable mitigation initiatives in annual CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
SECTION 7: PLAN MAINTENANCE
Galveston County, TX | Hazard Mitigation Plan 7-21
2022 Update
Jurisdiction Plan or Program
Last Update (if
known) How will this HMP be incorporated in the plan?
Floodplain
Management Plan
Incorporate flood risk assessment and hazard mapping
in future plan revisions. Seek to acquire high hazard
areas for public open space.
Stormwater
Management Program
June 2019 Incorporate flood risk assessment and hazard mapping
in future program revisions.
Emergency
Management Plan
Use risk assessments, hazard mapping, and mitigation
initiatives in future plan revisions.
La Marque (C) Capital Improvement
Plan
2022 Include applicable mitigation initiatives in annual CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
Disaster Debris
Management Plan
Use hazard mapping to determine potentially large
areas with debris after natural disasters.
Floodplain
Management Plan
Incorporate flood risk assessment and hazard mapping
in future plan revisions. Seek to acquire high hazard
areas for public open space.
Stormwater
Management Program
Incorporate flood risk assessment and hazard mapping
in future program revisions.
Parks Master Plan In progress Incorporate all risk assessments and hazard mapping,
as applicable in the development of the plan.
Imagine La Marque –
Renaissance District
Revitalization Plan
2017 Incorporate risk assessments and hazard mapping in
future revisions.
League City (C) Comprehensive Plan
2035
June 2013 Incorporate all risk assessments, hazard mapping, and
mitigation initiatives in the update of the safety and
land use elements, as applicable. Target growth for
low hazard areas.
Capital Improvement
Plan (2022-2026)
September 2021 Include applicable mitigation initiatives in annual CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
Disaster Debris
Management Plan
Use hazard mapping to determine potentially large
areas with debris after natural disasters.
Parks, Trails, and
Open Space Master
Plan
November 2017 Incorporate flood and wildfire risk assessment and
hazard mapping in future revisions.
Master Mobility Plan 2018 In future updates, use hazard mapping to determine
potential evacuation routes before and after natural
disaster events. Use transportation planning to guide
growth to safer areas.
Revitalizing Historic
League City –
Downtown
Redevelopment
2016 Incorporate risk assessments and hazard mapping in
future revisions.
Emergency
Management Plan
Use risk assessments, hazard mapping, and mitigation
initiatives in future plan revisions.
Santa Fe (C) Capital Improvement
Plan (2021-2022)
Include applicable mitigation initiatives in annual CIP
budgetary allotments. Plan major infrastructure
improvements in areas suitable for safe growth and
avoid capital expenditures in hazard areas.
Disaster Debris
Management Plan
Use hazard mapping to determine potentially large
areas with debris after natural disasters.
SECTION 7: PLAN MAINTENANCE
Galveston County, TX | Hazard Mitigation Plan 7-22
2022 Update
Jurisdiction Plan or Program
Last Update (if
known) How will this HMP be incorporated in the plan?
Floodplain
Management Plan
Incorporate flood risk assessment and hazard mapping
in future plan revisions. Seek to acquire high hazard
areas for public open space.
Stormwater
Management Program
Incorporate flood risk assessment and hazard mapping
in future plan revisions.
Tiki Island (V) Emergency
Management Plan
Use risk assessments, hazard mapping, and mitigation
initiatives in future plan revisions.
7.3 CONTINUED PUBLIC INVOLVEMENT
Galveston County and participating jurisdictions are committed to the continued involvement of the public in
the hazard mitigation process. This HMP update will continue to be posted on-line: http://www.gcoem.org
In addition, public outreach, and dissemination of the HMP will include:
• Links to the plan on municipal websites of each jurisdiction with capability.
• Continued utilization of existing social media outlets (Facebook, Twitter) to inform the public of natural
hazard events, such as floods and severe storms. Educate the public via the jurisdictional websites on
how these applications can be used in an emergency situation.
• Development of annual articles or workshops on flood hazards to educate the public and keep them
aware of the dangers of flooding
The Steering Committee representatives and the Galveston County HMP Coordinator will be responsible for
receiving, tracking, and filing public comments regarding this HMP. The public will have an opportunity to
comment on the plan via the hazard mitigation website at any time. The HMP Coordinator will maintain this
website, posting new information and maintaining an active link to collect public comments.
The public can also provide input at the annual review meeting for the HMP and during the next five-year plan
update. The Galveston County HMP Coordinator is responsible for coordinating the plan evaluation portion of
the meeting, soliciting feedback, collecting, and reviewing the comments, and ensuring their incorporation in
the five-year plan update as appropriate. Additional meetings might also be held as deemed necessary by the
planning group. The purpose of these meeting would be to provide the public an opportunity to express concerns,
opinions, and ideas about the mitigation plan.
The Steering Committee representatives shall be responsible to assure that:
• Public comment and input on the plan, and hazard mitigation in general, are recorded and addressed, as
appropriate.
• Copies of the latest approved plan (or draft in the case that the five-year update effort is underway) are
available for review, along with instructions to facilitate public input and comment on the HMP.
• Appropriate links to the Galveston County Hazard Mitigation Plan webpage are included on municipal
websites.
• Public notices are made as appropriate to inform the public of the availability of the plan, particularly
during HMP update cycles.
The Galveston County HMP Coordinator shall be responsible to assure that:
SECTION 7: PLAN MAINTENANCE
Galveston County, TX | Hazard Mitigation Plan 7-23
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Public and stakeholder comment and input on the plan, and hazard mitigation in general, are recorded and
addressed, as appropriate.
• Copies of the latest approved plan are available for review at appropriate county facilities along with
instructions to facilitate public input and comment on the plan.
• Public notices, including media releases, are made as appropriate to inform the public of the availability
of the plan, particularly during plan update cycles
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2022 Update
SECTION 8. PLANNING PARTNERSHIP
This section provides a description of the Galveston County’s HMP update planning partnership, their
responsibilities throughout the planning process, and the jurisdictional annexes developed as a result of their
plan update efforts.
8.1 PLAN MAINTENANCE PROCEDURES
The Federal Emergency Management Agency (FEMA)
encourages multi-jurisdictional planning for hazard
mitigation. All participating jurisdictions must meet the
requirements of Chapter 44 of the Code of Federal
Regulations (44 CFR):
“Multi-jurisdictional plans (e.g., watershed plans) may be
accepted, as appropriate, as long as each jurisdiction has
participated in the process and has officially adopted the
plan” [Section 201.6a(4)]
For the Galveston County HMP update, a Planning Partnership was formed to leverage resources and to meet
requirements for the federal Disaster Mitigation Action of 2000 (DMA) for as many eligible governments as
possible. Members of the Planning Partnership consisted of representatives from each jurisdiction. The DMA
defines a local government as follows:
Any county, municipality, city, town, township , public authority, school district, special district, intrastate
district, council of governments (regardless of whether the council of governments is incorporated as a
nonprofit corporation under State law), regional or interstate government entity, or agency or instrumentality
of a local government; any Indian tribe or authorized tribal organization, or Alaska Native village or
organization; and any rural community, unincorporated town or village, or other public entity.
Each participating planning partner has prepared a jurisdictional annex to this plan. These annexes, as well as
information on the process by which they were created, are contained in this volume.
8.2 INITIAL SOLICITATION AND LETTERS OF INTENT
Galveston County solicited the participation of all municipalities in the County at the commencement of this
project. Galveston County and 11 municipalities in the County participated in the update process and have met
the minimum requirements of participation as established by the County and Steering Committee.
8.3 PLANNING PARTNER EXPECTATIONS
The Planning Partners agreed to the following planning partner expectations, which were outlined in the letter
sent by Galveston County on September 20, 2021 and confirmed at the kick-off meeting held on September 29,
2021 (see Appendix C [Meeting Documentation] for details):
• Provide representation at regular planning group meetings and workshops.
• Be responsible for providing data and information as requested.
Members of the Planning Partnership have the
expertise to develop the plan and have their
jurisdiction’s authority to implement the mitigation
strategy developed during the planning process.
The Planning Partnership is responsible for
developing and reviewing draft sections of the plan,
updating their respective annex, creating the
mitigation strategy for their jurisdiction, and
adopting the final plan.
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• Review and comment on data and information compiled by the contract consultant relevant to their
jurisdiction.
• Be responsible for completing plan documents specific to your municipality, using provided templates
with guidance and assistance by the contract consultant.
• Assist with the identification of stakeholders within your community that should be informed and
potentially involved with the planning process.
• Facilitate public outreach efforts with residents and local stakeholders within your community using
materials provided by the contract consultant.
• Assist with the identification of strengths, weaknesses, opportunities, and obstacles to implementing
natural hazard mitigation within your community.
• Assist with the identification of past, ongoing and appropriate future mitigation strategies, and activities
within your municipality.
• Review and comment on plan documents, specifically the draft and final plans prior to submission to
TDEM and FEMA.
As described in Section 7 (Plan Maintenance), the planning partnership is intended to remain active beyond the
regulatory update to support plan maintenance. Regarding the composition of the Steering and Planning
Committees, it is recognized that individual commitments change over time, and it will be the responsibility of
each jurisdiction and its representatives to inform the HMP Coordinator of any changes in representation.
8.4 JURISDICTIONAL ANNEX PREPARATION PROCESS
New to the 2022 HMP, jurisdictional annexes were used to provide a unique, stand-alone guide to mitigation
planning for each participating jurisdiction. The Galveston County HMP Update is organized so that there is an
annex for Galveston County and for every participating jurisdiction. Section 9 (Jurisdictional Annexes) includes
an annex for every jurisdiction in Galveston County.
8.4.1 Data Collection
Each jurisdiction was paired with a contract consultant mitigation planner to work with the mitigation team to
update their annexes. Each jurisdiction was asked to participate in a municipal kick-off meeting, held on
September 29, 2021 to review participant expectations and the updated information needed to support the annex
update. It was made clear that the annexes are sections of the plan that can be enhanced if more information is
available to further customize any and all aspects of mitigation planning.
8.4.2 Hazard Ranking Exercise
The presentation of the risk assessment and hazard ranking for each jurisdiction was conducted December 21,
2021. At this meeting, the consultant presented the overall risk assessment for the hazards of concern and
distributed jurisdiction-specific handouts with risk assessment results relevant to each plan participant. In
addition, each planning partner was asked to review the ranked hazards specific for its jurisdiction. Refer to
Section 4.4 (Hazard Ranking) for the methodology of the hazard ranking process. The calculated ranking was
presented to each jurisdiction and they were asked to review the ranking and revise based on history of events,
probability of occurrence, and the potential impact on people, property, and the economy. In addition, each
jurisdiction was asked to rank their adaptive capacity for each hazard. Refer to Appendix B (Participation
Matrix) for the input submitted by each municipality. The objectives of this exercise were to familiarize the
partnership with how to use the risk assessment as a tool to support other planning and hazard mitigation
processes and to help prioritize types of mitigation actions that should be considered. Hazards that were ranked
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as “high” for each jurisdiction as a result of this exercise were considered to be priorities for identifying
appropriate mitigation actions, although jurisdictions also identified actions to mitigate “medium” or “low”
ranked hazards as appropriate.
8.4.3 Strengths Weaknesses Obstacles and Opportunities (SWOO) Exercise
After the draft risk assessment results were presented and hazard ranking exercise at the second Steering
Committee Meeting on November 18, 2021, attendees participated in a facilitated SWOO session to identify
strengths, weakness or challenges, obstacles, and opportunities in hazard mitigation for the County’s hazards of
concern. All SWOO results were compiled and provided as a resource to plan participants at the Mitigation
Strategy Workshop in December 2021. Refer to Appendix B (Participation Matrix) which provides the
information captured by meeting participants during the SWOO session.
8.4.4 Mitigation Strategy Workshop
A mitigation strategy workshop was conducted by the contracted planning consultant on December 2, 2021, for
all participating jurisdictions to support the development of the updated mitigation strategy. To assist with the
identification of implementable and action-oriented mitigation actions, the participating jurisdictions were
provided with tools to help identify mitigation strategies: public survey responses, potential mitigation actions
for each jurisdiction, and FEMA Mitigation Ideas. The purpose of this workshop was to guide the planning
partnership in completing this portion of the planning process and discuss how projects that are well developed
and documented are more quickly identifiable for selection when grants become available.
At the workshop, the Planning Partnership focused on developing problem statements based on the impacts of
hazards in the County and their communities. The results of the updated risk assessment, challenges and
opportunities identified during the capability assessment update and SWOO sessions, and information gathered
from the public survey were used to develop mitigation strategies. As a result, a mitigation workbook was
compiled with potential mitigation actions for the County and participating jurisdictions. This workbook helped
form a bridge between the hazard risk assessment, which quantifies impacts to each community, with the
development of achievable mitigation strategies. Mitigation development worksheets were filled out by each
municipality to identify additional problem statements and draft action worksheets were developed.
8.4.5 Municipal Support Conference Calls
In addition to the municipal kick-off meeting, municipal support conference calls were held throughout the
planning process. During these calls, the consultant worked one-on-one with the planning partners to complete
their jurisdictional annexes. Each section of the annex was discussed to ensure accuracy and completeness. This
included, but not limited to, the following:
• Reviewing the calculated hazard ranking for the jurisdiction and provide input to adjust the ranking as
necessary.
• Updating information regarding the jurisdiction’s capabilities and past integration of hazard mitigation
concepts.
• Identify mitigation initiatives that have reasonable potential to be accomplished within the lifespan of the
County HMP (five years), including both FEMA-eligible projects and those projects using funds from
non-FEMA sources.
8.4.6 Jurisdictional Annexes
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While the jurisdictional annex format is designed to document and assure local compliance with the DMA 2000
regulations, its greater purpose and function includes:
• Providing a locally-relevant synthesis of the overall mitigation plan that can be readily presented,
distributed, and maintained.
• Facilitating local understanding of the community’s risk to natural hazards.
• Facilitating local understanding of the community’s capabilities to manage natural hazard risk, including
opportunities to improve those capabilities.
• Facilitating local understanding of the efforts the community has taken, and plans to take, to reduce their
natural hazard risk.
• Facilitating the implementation of mitigation strategies, including the development of grant applications.
• Providing a framework by which the community can continue to capture relevant data and information
for future plan updates.
It is recognized that each jurisdiction’s annex is a “living” document and will continue to be improved as
resources permit. As such, its design is intended to promote and accommodate continued efforts to maintain the
annex to be current and to improve the effectiveness of the annex as the key tool, reference, and guiding
document by which the jurisdiction will implement hazard mitigation locally.
The following provides a description of the various elements of the jurisdictional annex.
Section 9.X.1: Hazard Mitigation Planning Team: Identifies the hazard mitigation planning team who
provided input during the planning process. Further detail is provided in Section 2 (Planning Process) and
Appendix B (Participation Matrix).
Section 9.X.2: Jurisdictional Profile: Provides an overview and profile of the jurisdiction, including an
identification of areas of known and anticipated future development and the vulnerability of those areas to the
hazards of concern.
Section 9.X.3: Jurisdictional Capability Assessment and Integration: This subsection provides an inventory
and evaluation of the jurisdiction’s tools, mechanisms, and resources available to support hazard mitigation and
natural hazard risk reduction. Within the municipal annexes, tables provide an inventory of the municipality's
planning and regulatory, administrative, and technical, and fiscal, capabilities, respectively. Further, another
table identifies the municipality's level of participation in state and federal programs designed to promote and
incentivize local risk reduction efforts. Further information regarding Federal, State, and local capabilities may
be found in the Capability Assessment portion of Section 5.
Section 9.X.4: National Flood Insurance Program (NFIP) Compliance: A tabular summary of the specific
information on the management and regulation of the regulatory floodplain, including current and future
compliance with the NFIP.
Section 9.X.5: Growth/Development Trends: Identifies of areas of known and anticipated future
development and the vulnerability of those areas to the hazards of concern.
Section 9.X.6: Jurisdictional Risk Assessment:
• Hazard Extent and Location: Each annex includes a map (or series of maps) illustrating identified hazard
zones and critical facilities. Further, these maps show areas of known or anticipated future development,
as available and provided by the jurisdiction.
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• Hazard Event History: Identifies hazard events that have caused significant impacts within the
jurisdiction, including a summary characterization of those impacts as identified by the jurisdiction. The
documentation of events and losses is critical to supporting the identification and justification of
appropriate mitigation actions, including providing critical data for benefit-cost analysis. It is recognized
that this “inventory” of events and losses is a work-in-progress and may continue to be improved as
resources permit. As such, the lack of data or information for a specific event does not necessarily mean
that the jurisdiction did not suffer significant losses during that event.
• Hazard Ranking and Vulnerabilities: This subsection provides information regarding each plan
participant’s vulnerability to the identified hazards. Full data and information on the hazards of concern,
the methodology used to develop the vulnerability assessments, and the results of those assessments that
serve as the basis of these local risk rankings may be found in Section 4 (Risk Assessment).
Section 9.X.7: Mitigation Strategy and Prioritization: This section discusses and provides the status of past
mitigations actions and status, describes proposed hazard mitigation initiatives, and prioritization.
• Past Mitigation Initiative Status: Where applicable, a review of progress on the jurisdiction’s prior
mitigation strategy is presented, identifying the disposition of each prior action, project, or initiative in the
jurisdiction’s updated mitigation strategy. Other completed or on-going mitigation activities that were
not specifically part of a prior local mitigation strategy may be included in this sub-section as well.
• Additional Mitigation Efforts: Other completed or on-going mitigation activities that were not
specifically part of a prior local mitigation strategy may be included in this subsection as well.
• Proposed Hazard Mitigation Initiatives for the Plan Update: Table 9.X-16 presents the jurisdiction’s
updated mitigation strategy. As indicated, applicable mitigation actions, projects and initiatives are further
documented on an Action Worksheet which provides details on the project identification, evaluation,
prioritization, and implementation process. Table 9.X-17 provides a summary of the local mitigation
strategy prioritization process discussed in Section 6 (Mitigation Strategy).
8.4.7 Annex Review
Workshops and additional meetings (via email and/or teleconference) to complete the jurisdictional annexes
were held with the Steering Committee and Planning Partnership throughout the planning process. In preparation
for the draft plan public review, each jurisdiction was asked to have their ‘mitigation team’ review their annex
to ensure it was complete and accurate for posting to the Galveston County Office of Emergency Management’s
mitigation website. To demonstrate broad and comprehensive review and input, each jurisdiction collected
signatures from these representatives. Refer to Appendix B (Participation Matrix) to review the annex signature
pages.
In summary, all participating communities and the County completed the planning partner expectations and
annex-preparation process. Details regarding these meetings are described further in Section 2 (Planning
Process) and Section 6 (Mitigation Strategy). Completed jurisdictional annexes are presented in Section 9
(Jurisdictional Annexes).
8.5 COVERAGE UNDER THE PLAN
The County and 11 jurisdictions met the participation requirements specified by the Steering Committee. Any
non-participating local jurisdiction within the Galveston County planning area can “dock” to this plan in the
future following the linkage procedures defined in Appendix G (Linkage Procedures).
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Table 8-1 lists the status of each participating jurisdiction and their ultimate status in this plan update. Refer to
Appendix B (Participation Matrix) and Appendix C (Meeting Documentation) for details on participation and
meeting attendance.
Table 8-1. Jurisdictional Status
Municipality
Attended
Workshops
and/or Meetings
and Project
Calls
Provided Update on
Past Projects
Submitted
Mitigation
Actions for
Current Plan
Seeking Approval
for Adoption
(meets all previous
requirements)
Galveston County X X X X
Bayou Vista (C) X X X X
Clear Lake Shores (C) X X X X
Dickinson (C) X X X X
Friendswood (C) X X X X
Hitchcock (C) X X X X
Jamaica Beach (C) X X X X
Kemah (C) X X X X
La Marque (C) X X X X
League City (C) X X X X
Santa Fe (C) X X X X
Tiki Island (V) X X X X
N/A = Not applicable.
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Galveston County, TX | Hazard Mitigation Plan Ref-1
2022 Update
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Galveston County, TX | Hazard Mitigation Plan Ref-3
2022 Update
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