2025 County of Los Angeles
All-Hazards Mitigation Plan
Chief Executive%SœJN -%SœJN of Emergency Management
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1 of
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County of Los Angeles
All-Hazards Mitigation Plan
Acknowledgement
The Los Angeles County Board of Supervisors gratefully acknowledges the following agencies/jurisdictions who contributed to the development of this plan.
County Departments
Aging and Disabilities
UVNSxNJqpVvN%SœJN
UVNS1qmpAV_AIV]Vpy%SœJN
Beaches and Harbors
Economic Opportunity
Health Services
Human Resources
Parks and Recreation
Public Health
Public Social Services
Public Works
Regional Planning
Fire (LACoFD)
Internal Services
Sheriff (LASD)
Disaster Management Area Coordinators
State of California
A]VSal_VAavNl_al¯m%SœJNaS^NlTN_Jy1NlvVJNmA]%1 California State Council on Developmental Disabilities (SCCD) External Partners
Access Services
Alzheimer’s Association
Catholic Charities
City of Beverly Hills
City of Long Beach
Disability Community Resource Center
Eastern Los Angeles Regional Center
Emergency Network Los Angeles
Habitat for Humanity
Harbor Regional Center
Lanterman Regional Center
!am_TN]Nmaq_py%SœJNaSLqJApVa_
Los Angeles County Sanitation Districts
Los Angeles County Metropolitan
Transportation Authority
Los Angeles Regional Food Bank
Neighborhood Legal Services of Los Angeles
County
Puente Hills Habitat Preservation Authority
South Central Los Angeles Regional Center
Westside Regional Center
Cover Photo Credits: !am_TN]Nmaq_pyUVNSxNJqpVvN%SœJNaq_pywVLNa^^q_VJApVa_m lA_JU
Los Angeles County Department of Public Works
County of Los Angeles
All-Hazards Mitigation Plan
Table of Contents
Acknowledgement ................................................................................................................. 1 Letter of Promulgation ........................................................................................................... 2 1 _plaLqJpVa_-qliamNA_L1JaiN ................................................................................ 6
1.1 Purpose ...................................................................................................................... 7
1.2 Scope ......................................................................................................................... 7
1.3 Legal Authority and Requirements ......................................................................... 7
1.4 Plan Organization ..................................................................................................... 8 2 Planning Process ............................................................................................................. 9
2.1 Overview of the Planning Process ........................................................................ 10
2.2 Stakeholder Engagement ...................................................................................... 13
2.3 Public Involvement and Outreach ........................................................................ 18
2.4 Review and Incorporation of Existing Plans and Reports .................................. 19 3 a^^q_Vpy-laœ]N ........................................................................................................ 22
3.1 Los Angeles County Overview .............................................................................. 23
3.2 Geography and Land Use ..................................................................................... 24
3.3 Social Vulnerability ................................................................................................. 25
3.4 Economy and Critical Infrastructure ..................................................................... 28
3.5 Climate and Environmental Conditions ............................................................... 29
3.6 Regional Collaboration and Planning Efforts ...................................................... 30
3.7 Implications for Hazard Mitigation Planning ....................................................... 31 4 Climate Change ............................................................................................................ 32
4.1 Climate Change Overview .................................................................................... 33
4.2 _pNTlApV_T]V^ApNUA_TNV_paA|AlL-laœ]Nm ............................................... 34
4.3 Climate Mitigation Strategies ................................................................................ 36
4.4 Climate Change Conclusion ................................................................................. 37 County of Los Angeles
All-Hazards Mitigation Plan
5 Integrating Access and Functional Needs (AFN) into Hazard Mitigation .............. 38
5.1 AFN Introduction .................................................................................................... 39
5.2 Inclusion of AFN and Vulnerable Populations in Planning ................................ 39
5.3 Assessment of AFN Needs .................................................................................... 40
5.4 Coordination with AFN Support Agencies .......................................................... 42
5.5 AFN Conclusion ...................................................................................................... 42 6 A|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p ............................................................... 43
6.1 A|AlLLN_pVœJApVa_%vNlvVNw ............................................................................. 44
6.2 :V]LœlN ..................................................................................................................... 49
6.3 Earthquake .............................................................................................................. 57
6.4 Extreme Heat ........................................................................................................... 67
6.5 Drought .................................................................................................................... 74
6.6 Flooding .................................................................................................................. 82
6.7 Dam Failure ............................................................................................................. 92
6.8 Land Movement .................................................................................................... 102
6.9 Tsunami .................................................................................................................. 114
6.10 Severe Wind and Tornado ............................................................................... 120
6.11 Mass Violence .................................................................................................... 130
6.12 Cybersecurity Incidents .................................................................................... 135
6.13 Transportation Incidents ................................................................................... 142
6.14 Public Health Emergencies .............................................................................. 147 7 Mitigation Strategy ...................................................................................................... 152
7.1 Mitigation Strategy Overview .............................................................................. 153
7.2 Mitigation Goals and Objectives ........................................................................ 153
7.3 Existing Mitigation Capabilities .......................................................................... 155
7.4 LN_pVœJApVa_A_L_A]ymVmaS"VpVTApVa_1plApNTVNm ......................................... 172 County of Los Angeles
All-Hazards Mitigation Plan
7.5 Status of Previous Mitigation Efforts ................................................................... 184
7.6 Prioritization and Implementation of Mitigation Actions ................................. 186
7.7 Integration with Other Plans ............................................................................... 189
7.8 Mitigation Action Plan .......................................................................................... 191 8 Plan Maintenance ........................................................................................................ 196
8.1 Community Participation in Plan Maintenance ................................................. 197
8.2 "a_VpalV_TvA]qApVa_A_L"AV_pN_A_JN......................................................... 198
8.3 Criteria for Updating the Hazard Mitigation Plan ............................................. 199
8.4 Plan Update ........................................................................................................... 200
8.5 Integration with Other Plans ............................................................................... 201 9 Plan Adoption .............................................................................................................. 202
9.1 Plan Adoption Overview ...................................................................................... 203 Appendices ......................................................................................................................... 204 County of Los Angeles
All-Hazards Mitigation Plan
1 _plaLqJpVa_-qliamN
and Scope
County of Los Angeles
All-Hazards Mitigation Plan
1.1 Purpose
The 2025 All-Hazard Mitigation Plan (AHMP) was developed in collaboration with a wide range of stakeholders representing County Departments and other external mpA\NUa]LNlmSla^JVpVNm ]aJA]qpV]VpVNm _a_-TavNl_^N_pA]alTA_V|ApVa_mA_LmpApN agencies. The purpose of this AHMP is to form the strategic-level foundation for hazard mitigation efforts undertaken by the County of Los Angeles. The 2025 AHMP is an update to the 2020 version of the plan and seeks to maintain the County’s continuing commitment to hA|AlL^VpVTApVa_AmAJlVpVJA]mpNiV_lNLqJV_TUA|AlLlVm\m^ A\V_T Ja^^q_VpVNmmASNlA_LIqV]LV_TJaq_pywVLNlNmV]VN_JN
1.2 Scope
A|AlL^VpVTApVa_VmLNœ_NLV_pUNaLNaSNLNlA]0NTq]ApVa_m0 Am¬A_ymqmpAV_NL action taken to reduce or eliminate the long-term risk to human life and property from UA|AlLm3UVm"-VLN_pVœNmA_Lilaœ]NmUA|AlLmA_A]y|NmpU NiNai]NA_LJlV tical V_SlAmplqJpqlNAplVm\A_LilavVLNmAmNlVNmaS^VpVTApVa_mpl ApNTVNmAV^NLAplNLqJV_T hazard risk. The plan also describes actions to integrate vulnerable communities including people with Access and Functional Needs (AFN) into hazard mitigation planning and other efforts. The AHMP is intended to function as a strategic plan for UA|AlL^VpVTApVa_A_LwUV]N_apA_N^NlTN_Jyi]A_Ja^i]N^N_pm pUN!am_TN]Nm County Operational Area Emergency Operations Plan. This plan contains mitigation strategies for County-owned facilities or other areas under the jurisdiction of the County of Los Angeles. Hazard mitigation strategies for incorporated cities within Los Angeles County may be found in that city’s hazard mitigation plan.
1.3 Legal Authority and Requirements
Historically local hazard mitigation planning has been driven by federal law. The Disaster Mitigation Act (DMA) of 2000 amended the Robert T. Stafford Disaster Relief and Emergency Assistance Act of 1988 with new requirements for hazard mitigation.
The DMA aSN^iUAmV|NLpUN_NNLSalmpApNplVIA]A_L]aJA]N_pVpV NmpaJ]amN]y coordinate on hazard mitigation efforts and formed the legal basis for the Federal Emergency Management Agency’s (FEMA) current mitigation plan requirements in order to utilize Hazard Mitigation Assistance grant programs. This plan was prepared County of Los Angeles
All-Hazards Mitigation Plan
pursuant to the requirements set forth in the DMA of 2000 and other FEMA hazard mitigation policy guidance.
1.4 Plan Organization
The AHMP is organized into nine (9) mNJpVa_mNxJ]qLV_TpUNiiN_LVJNm including:
1. Introduction: VmJqmmNmpUNiqliamNmJaiNA_L]NTA]AqpUalVpyaSpUNi]A_
2. Planning Process: Describes the planning process that was undertaken by the Hazard Mitigation Planning Committee to create this updated 2025 AHMP .
3. a^^q_Vpy-laœ]N %vNlvVNwmpUNq_VkqNTNaTlAiUVJJ]V^ApVJN_vVla_^N_pA] and socioeconomic factors that make up Los Angeles County and their implications for hazard mitigation planning.
4. Climate Change: Outlines the impacts of climate change in Los Angeles County and potential mitigation and adaptation measures.
5. Integrating AFN into Hazard Mitigation: Discusses strategies for integrating people with Access and Functional Needs (AFN) into prevention and hazard mitigation efforts.
6. A|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p LN_pVœNmA_Lilaœ]Nm nine (9) natural and four (4) human-caused hazards that may impact Los Angeles County including: wV]LœlNNAlpUkqA\NNxplN^NUNApLlaqTUpŔaaLV_TLA^SAV]ql N ]A_L^avN^N_ppmq_A^VmNvNlNwV_LA_Lpal_ALa^AmmvVa]N_JNJyINlmNJqlVpy V_JVLN_pmplA_mialpApVa_V_JVLN_pmA_LiqI]VJUNA]pUN^NlTN_JVNm
7. Mitigation Strategy: Delineates the overall strategy for the County’s hazard ^VpVTApVa_NSSalpmV_J]qLV_TTaA]mA_LaI[NJpVvNmNxVmpV_T^VpVTApVa_JAiAIV]VpVNm and an analysis of mitigation actions.
8. Plan Maintenance: Outlines how the plan will be maintained annually ahead of pUN_NxpSq]]i]A_qiLApNV_œvNyNAlm
9. Plan Adoption: Discusses updates to the plan and implementation following plan adoption.
a]]awV_TpUNmNmNJpVa_mpUNlNAlNA_ALLVpVa_A] six (6) appendices with supporting ^ A p N l V A ] m m q J U A m U A | A l L ^ A i m ^ N N p V _ T ^ V _ q p N m S l a ^ i ] A _ _ V _ T ^ NNpV_Tm A_L information about the public engagement efforts during the planning process.
County of Los Angeles
All-Hazards Mitigation Plan
2 Planning Process
County of Los Angeles
All-Hazards Mitigation Plan
2.1 Overview of the Planning Process
The 2025 Los Angeles County All-Hazard Mitigation Plan (AHMP) update builds upon the robust all-hazard planning framework established by the 2020 All-Hazards "VpVTApVa_-]A_wUV]NV_JalialApV_T_Nw^NpUaLa]aTVNmmpA\NUa ]LNlN_TATN^N_p and compliance requirements. The planning process for this update emphasized V_J]qmVvVpy plA_miAlN_Jy A_L pUN V_pNTlApVa_ aS N^NlTV_T J]V^ApN ALAipApVa_ considerations.
3UVmi]A__V_TilaJNmmSa]]awNLAmplqJpqlNLiUAmNLAiilaAJUA] VT_NLwVpU"¯m !aJA]"VpVTApVa_-]A__V_T-a]VJyqVLN 0lNkqVlN^N _pmA_LTqVLA_JN Sla^pUNA]VSal_VAavNl_al¯m%SœJNaS^NlTN_Jy1NlvVJNmA]%1 3UVmAiilaAJU began witUila[NJpV_VpVApVa_wUNlNpUNmJaiNpV^N]V_NA_LmpA\NUa]LNlmwNlNLNœ_NL Stakeholder and public engagement were prioritized to ensure representation from LVvNlmNTlaqimV_J]qLV_TUVmpalVJA]]yq_LNllNilNmN_pNLJa^^q_V pVNmA_LJ]V^ApN - vulnerable populations.
Data Ja]]NJpVa_A_LA_A]ymVm]NvNlATNLqiLApNLUA|AlLJ]V^ApNA_Lvq]_NlAIV]VpyLApA Sla^]aJA]mpApNA_LSNLNlA]maqlJNmilavVLV_TASaq_LApVa_ SalN_UA_JNLlVm\A_L vq]_NlAIV]VpyAmmNmm^N_pmA|AlLilaœ]NmwNlNqiLApNLpaV_J]qLNJ]V^ApNila[NJpVa_m and cascading impact scenarios. Mitigation strategies were revised and prioritized with a renewed focus on climate resilience and nature-based solutions. Strategies were also developed incorporating people with access and functional needs throughout each comia_N_paSpUN"-V_A]]y^NpUaLmSal^a_VpalV_TA_LNvA]qApVa_aS^VpVTApVa_ NSSalpmwNlNLNœ_NLV_pUNi]A_^AV_pN_A_JNA_LV^i]N^N_pApVa_ mplApNTy3AI]N-1 provides a timeline of the major plan update tasks and milestones over the planning process.
Table 2-1 AMHP Planning Timeline
Date 3Am\m People Involved
February
2025
0NvVNwNLpUN"-A_LVLN_pVœNL
components that require update.
OEM AHMP Project
Team
Collected and reviewed existing
LaJq^N_pmV_J]qLV_TpUN3UlNApA_L
A|AlLLN_pVœJApVa_A_L0Vm\
Assessment (THIRA) along with resources
for people with access and functional
OEM AHMP Project
Team
County of Los Angeles
All-Hazards Mitigation Plan
Date 3Am\m People Involved
needs and people experiencing
homelessness.
February
2025
Met with state Hazard Mitigation
Planning Team.
OEM AHMP Project
3NA^A]%1
Mitigation Division
LN_pVœNLpUNV_VpVA]]VmpaSmpA\NUa]LNlm
and ensured organizations that work with
and represent people with access and
functional needs were engaged in the
planning process. External stakeholders
V_J]qLN_NVTUIalV_TJa^^q_VpVNm]aJA]
A_LlNTVa_A]ATN_JVNmA_LapUNlm
OEM AHMP Project
Team
Conducted 2025 AHMP Kickoff Meetings
with internal stakeholders.
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqiA]
OES Mitigation Division
NpNl^V_NLUA|AlLmpaINilaœ]NL
V_J]qLV_TIapU_ApqlA]VNwV]L]A_LœlN
NAlpUkqA\NNpJ A_LUq^A_-JAqmNLVN
JyINlmNJqlVpypNllalVm^NpJ
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
Group
Drafted initial sections of the 2025 AHMP . OEM AHMP Project Team
Shared drafts of initial sections with
internal and external stakeholders for
their review.
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
laqiA]%1
Mitigation Division
Met with internal and external
stakeholders to obtain feedback on draft
plan elements.
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
laqiA]%1
Mitigation Division
County of Los Angeles
All-Hazards Mitigation Plan
Date 3Am\m People Involved
March
2025
Developed the Public Outreach
Engagement Plan to collect feedback
from the public on the public draft of the
2025 AHMP .
OEM AHMP Project
3NA^A]%1
Mitigation Division
Drafted subsequent sections of the 2025
AHMP including updating existing
mitigation actions and developing new
mitigation actions as needed.
OEM AHMP Project
Team
Shared drafts of the subsequent sections
with internal and external stakeholders
for their review.
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
laqiA]%1
Mitigation Division
Met with internal and external
stakeholders to obtain feedback on
subsequent draft plan elements.
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
laqiA]%1
Mitigation Division
April/May
2025
lASpNLœ_A]mNJpVa_maSpUN
"-
and produced a Final Draft AHMP .
OEM AHMP Project
Team
Shared Final Draft of the AHMP with
internal and external stakeholders for
their review.
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
laqiA]%1
Mitigation Division
Met with internal and external
stakeholders to obtain feedback on
subsequent Final Draft AHMP .
OEM AHMP Project
3NA^_pNl_A]aq_py
1pA\NUa]LNllaqi
External Stakeholder
laqiA]%1
Mitigation Division
Produced Final AHMP . OEM AHMP Project
Team
County of Los Angeles
All-Hazards Mitigation Plan
2.2 Stakeholder Engagement
Inclusive stakeholder involvement was essential to the planning process. The County N_mqlNL IlaAL lNilNmN_pApVa_ A_L iAlpVJViApVa_ Ja_mVmpN_p wVpUp U N ´ : U a ] N a^^q_VpyiilaAJU´aqp]V_NLV_pUN%iNlApVa_A]lNA^NlTN_Jy%iNlApVa_m Plan (OAEOP). Key stakeholders that comprised the Hazard Mitigation Advisory Committee included:
• aq_pyLNiAlp^N_pmmqJUAmIqp_ap]V^VpNLpa-qI]VJ:al\m-qI]VJNA]pUA_L Regional Planning.
• Cities within the operational area (OA) and neighboring communities through Disaster Management Area Coordinators (DMACs) and city representation. •N o n -TavNl_^N_pA] alTA_V|ApVa_m #%m V_J]qLV_T N_vVla_^N_pA] A_L disability advocacy groups.
• Special District partners managing critical infrastructure. • Representatives of academia and school districts.
• Community representatives from Access and Functional Needs (AFN) populations and historically underrepresented populations. 0NTq]Al^NNpV_Tmwal\mUaimA_LSaJqmTlaqimwNlNUN]LpaTApUNlV_iqpA_LlNœ_N mitigation strategies. Stakeholders were contacted and invited to participate in the 2025 AHMP planning process through email (please see email template in Appendix B-3). Stakeholder SNNLIAJ\wAmLaJq^N_pNLA_LV_JalialApNLV_papUNi]A_N_mqlV_T diverse perspectives informed the process. Tables 2-2 and 2-3 includes a list of representatives of each agency that contributed to the planning process.
Table 2-2 Hazard Mitigation Advisory Committee – _pNl_A]1pA\NUa]LNllaqi Department/
Agency
Name Title Planning Contribution
Los Angeles County
%SœJNaS
Emergency
Management (OEM
AHMP Project
Team)
Michael
Morin
Emergency
Management
Coordinator
q_JpVa_NLAm]NALi]A__Nlm
]NLi]A__V_T^NNpV_Tm
LlASpNLi]A_lNvVNwNL
mitigation actions submitted
by departments.
Matthew
Topoozian
Emergency
Management
Coordinator
County of Los Angeles
All-Hazards Mitigation Plan
Department/
Agency
Name Title Planning Contribution
Karen Haro Emergency
Management
Coordinator
Girma
Wollela
Emergency
Management
Coordinator
Los Angeles County
Department of
Aging and
Disabilities
Mike Tsao Administrative
Deputy
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Henry
Lopez
Program
Manager
Carin
Anderson
Administrative
Services
Manager
Keilah
Kelso
Administrative
Services
Manager
Los Angeles County
Chief Executive
%SœJN– Anti-
0AJVm^VvNlmVpy
and Inclusion
Initiative
Cesar
Sanchez
Senior Analyst ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Chief Executive
%SœJN– Homeless
Initiative
Onnie
Williams III
Principal Analyst ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Chief Sustainability
%SœJN
Matthew
Gosner
Climate
Resilience
%SœJNl
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
County of Los Angeles
All-Hazards Mitigation Plan
Department/
Agency
Name Title Planning Contribution
Los Angeles County
Department of
Beaches and
Harbors
Katharine
de la Cruz
Administrative
Services
Manager
Attended planning ^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Vanessa
Huerta
1ASNpy%SœJNl
Los Angeles County
Department of
Economic
Opportunity
Maritza
Dubie
Human Services
Administrator
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Department of
Health Services
Elaine
Forsyth
Senior Nursing
Instructor
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Isabel
Sanchez
Disaster
Services
Specialist
Los Angeles County
Department of
Human Resources
Kevin
Halbritter
Deputy
Compliance
%SœJNl
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Department of
Parks and
Recreation
Ramon
Bernal
Disaster
Services Analyst
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Department of
Public Health
Elizabeth
Rubin
Epidemiologist ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Department of
Public Social
Services
Manuel
Gutierrez
Disaster
Services Analyst
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
County of Los Angeles
All-Hazards Mitigation Plan
Department/
Agency
Name Title Planning Contribution
Los Angeles County
Department of
Public Works
Joseph
Marble
Disaster
Services Analyst
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Loni Eazell Disaster
Services
Specialist
Los Angeles County
Department of
Regional Planning
Thuy Hua Supervising
Planner
ppN_LNLi]A__V_T^NNpV_Tm
reviewed section LlASpmA_L
provided feedback.
Edgar De
La Torre
Principal
Regional
Planner
Los Angeles County
Fire Department
Nick
Duvally
Deputy Fire
Chief
ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Internal Services
Department
Juan-Raul
Cardenas
GIS Analyst ppN_LNLi]A__V_T^NNpV_Tm
lNvVNwNLmNJpVa_LlASpmA_L
provided feedback.
Los Angeles County
Sheriff’s
Department
Jordan
Kennedy
Sergeant ppN_LNLi]A__V_T^NNpV_Tm
reviewed section LlASpmA_L
provided feedback.
Table 2-3 Hazard Mitigation Advisory Committee – External 1pA\NUa]LNllaqi Department/Agency Planning Contribution
Access Services ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_ LlASpmA_LilavVLNLSNNLIAJ\
Alzheimer’s Association
California
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
A]VSal_VAavNl_al¯m%SœJN
of Emergency Services
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Catholic Charities ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_ LlASpmA_LilavVLNLSNNLIAJ\
County of Los Angeles
All-Hazards Mitigation Plan
Department/Agency Planning Contribution
City of Beverly Hills
Emergency Management
Division
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
City of Long Beach Disaster
Preparedness & Emergency
Communications
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
City of Los Angeles
Emergency Management
Department
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disability Community
Resource Center
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Disaster Management Area
aalLV_ApallNA
Attended i]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Eastern Los Angeles
Regional Center
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Emergency Network Los
Angeles
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLsection
LlASpmA_LilavVLNLSNNLIAJ\
Habitat for Humanity ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_ LlASpmA_LilavVLNLSNNLIAJ\
County of Los Angeles
All-Hazards Mitigation Plan
Department/Agency Planning Contribution
Harbor Regional Center ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_ LlASpmA_LilavVLNLSNNLIAJ\
Lanterman Regional Center ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_ LlASpmA_LilavVLNLSNNLIAJ\
!am_TN]Nmaq_py%SœJNaS
Education
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Los Angeles County
Sanitation Districts
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Los Angeles Metropolitan
Transportation Authority
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Los Angeles Regional Food
Bank
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Neighborhood Legal
Services of Los Angeles
County
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Puente Hills Habitat
Preservation Authority
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
South Central Los Angeles
Regional Center
ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_
LlASpmA_LilavVLNLSNNLIAJ\
Westside Regional Center ppN_LNLi]A__V_T^NNpV_TmlNvVNwNLmNJpVa_ LlASpmA_Lprovided feedback.
2.3 Public Involvement and Outreach
-qI]VJaqplNAJUNSSalpmAV^NLpaSampNlplA_miAlN_JyV_J]qmVvVpyA_LSalpVSyiqI]VJplqmp The County engaged the public during the planning process through multiple media formats to share information and collect feedback taking into account language and other access and functional needs. A rolling outreach strategy was used to ensure that AmNAJUmNJpVa_wAmLlASpNLA_LlNvVNwNLIyi]A__V_TmpA\NUa]LNlmVpwAmJa_JqllN_p]y ^ALNAvAV]AI]NSaliqI]VJJa^^N_pAly3aAJJa^i]VmUpUVmNAJUmNJpVa_wAmiampNL to the Los Angeles County Hazard Mitigation Program website as it was completed by the planning team. A survey designed to gauge community perceptions of hazard risks and mitigation priorities was used on the website (Appendix D). This approach ensured that the public was a key partner in every step of the planning process and had a voice as County of Los Angeles
All-Hazards Mitigation Plan
each section was being developed by the planning team. A social media campaign using all LA County OEM social media channels was initiated to direct the public to the survey.
3a ALLlNmm NkqVpy pAlTNpNL aqplNAJU NSSalpm SaJqmNL a_ N_TATV_T UVmpalVJA]]y q_LNllNilNmN_pNL Ja^^q_VpVNm A_L # iaiq]ApVa_m qmV_T ^q]pV]V_TqA] A_L AJJNmmVI]N^ApNlVA]mA_LJq]pqlA]]yAiilailVApNpNJU_VkqNmmVLNSla^iqI]VJaqplNAJU stakeholders that wal\wVpUallNilNmN_piNai]NwVpUAJJNmmA_LSq_JpVa_A]_NNLm iNai]N NxiNlVN_JV_T Ua^N]Nmm_Nmm A_L A LVvNlmN AllAy aS Jq]pqlA] Tlaqim wNlN targeted to participate in the Hazard Mitigation Advisory Committee. These measures ensured that the public had meaningful opportunities to participate in shaping the plan.
2.4 Review and Incorporation of Existing Plans and Reports The planning process included a comprehensive review of existing documents and protocols to ensure consistency and alignment. The 2020 All-Hazards Mitigation Plan mNlvNLAmpUNSaq_LApVa_A]LaJq^N_pSalpUVmqiLApNLLVpVa_A]]y\NyJa_JNipmSla^ the 2023 Operational Area Emergency Operations Plan (OA%- mqJUAm^NlTN_Jy 1qiialpq_JpVa_m1m A_LLVmAmpNl^A_ATN^N_pAlNAmwNlNV_ pNTlApNL3UN!am Angeles County Climate Vulnerability Assessment provided valuable insights into J]V^ApNlVm\mA_LmaJVA]mN_mVpVvVpywUV]N]aJA]]V^ApNJpVa_-]A_mN_mqlNLA]VT_^N_p with mq_VJViA]J]V^ApNALAipApVa_V_VpVApVvNmqlpUNl^alNpUN41303UlNAp A_LA|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p ilavVLNLJlVpVJA] LApASalVLN_pVSyV_T Nva]vV_TpUlNApmA_LJAiAIV]VpypAlTNpmN_UA_JV_TpUNAJJqlAJy A_LlN]NvA_JNaSpUN plan. The demographic data from the 2020 U.S. Census was utilized to ensure an AJJqlApNlNilNmN_pApVa_aS!am_TN]Nmaq_pyµmiaiq]ApVa__awNmpV^ApNLApavNl ^V]]Va_lNmVLN_pm3UNLN^aTlAiUVJIlNA\Law_V_J]qLNmÈVmiA_VJal!ApV_aÈ :UVpN
ÈmVA_ÈSlVJA_^NlVJA_A_LÈapUNlwVpUavNl ÈmiNA\V_TA ]A_TqATNapUNlpUA__T]VmUApUa^NN^iUAmV|V_TpUN_NNLSal^ q]pV]V_TqA]A_L culturally appropriate outreach.
County of Los Angeles
All-Hazards Mitigation Plan
Table 2-4 xVmpV_T-]A_m"AimA_L0Nialpm
-]A_"Aial0Nialp Information to be Incorporated into the 2025 Updated AHMP
Los Angeles County
Operational Area
Emergency Operations
Plan (2023)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
Risk Assessment and Section 7: Mitigation Strategy
Los Angeles County 2035
General Plan (2024)
Safety element mitigation policies used to inform
Section 7 – Mitigation Strategy
Los Angeles County
Comprehensive
Floodplain Management
Plan (2021)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
Risk Assessment and Section 7: Mitigation Strategy
SalN]N^N_pmlN]ApNLpaŔaaLUA|AlLm
County of Los Angeles
Floodplain Management
Plan Progress Report from
(2024)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
Risk Assessment and Section 7: Mitigation Strategy
SalN]N^N_pmlN]ApNLpaŔaaLUA|AlLm
County of Los Angeles
Repetitive Loss Area
Analysis Progress Report
(2021)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
Risk Assessment and Section 7: Mitigation Strategy
SalN]N^N_pmlN]ApNLpaŔaaLUA|AlLm
Los Angeles County 2045
Climate Action Plan (2024)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
0Vm\mmNmm^N_p1NJpVa_7"VpVTApVa_1plApNTyA_L
Section 4: Climate Change for elements related to
hazard risk posed by climate change
Los Angeles County Fire
Department Fire Plan
(2023)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
Risk Assessment and Section 7: Mitigation Strategy
SalN]N^N_pmlN]ApNLpawV]L]A_LœlNUA|AlLm
Our County: Los Angeles
Countywide Sustainability
Plan (2019)
Used to inform Section 6A|AlLLN_pVœJApVa_A_L
0Vm\mmNmm^N_p1NJpVa_7"VpVTApVa_1plApNTyA_L
Section 4: Climate Change for elements related to
hazard risk
posed by climate change
Los Angeles County
Homeless Initiative
Strategy Plan (2022)
Used to inform vulnerable populations information
across all sections of the plan.
Disability Among Adults in
Los Angeles County
(2019)
Used to inform vulnerable populations information
across all sections of the plan.
Southern California
Earthquake Data Center’s
Earthquake Catalogs
(Current as of 2025)
Historical seismic information used in Section 6:
A|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p
County of Los Angeles
All-Hazards Mitigation Plan
-]A_"Aial0Nialp Information to be Incorporated into the 2025 Updated AHMP
Maritime Tsunami
Response Playbooks:
Background Information
and Guidance for
Response and Hazard
Miti
gation Use (2016)
Historical tsunami information used in Section 6:
A|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p
FEMA Flood Insurance
1pqLy!am_TN]Nm
aq_p
yA]VSal_VA
VmpalVJA]ŔaaLV_Sal^ApVa_qmNLV_1NJpVa_6:
A|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p
U.S. Geological Survey
(USGS): Rainfall and
Landslides in Southern
California (2015)
Historical landslide information used in Section 6:
A|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p
Burn Scar Information and
Maps
VmpalVJA]œlNV_Sal^ApVa_qmNLV_1NJpVa_6: Hazard
LN_pVœJApVa_A_L0Vm\mmNmm^N_p
County of Los Angeles
All-Hazards Mitigation Plan
3 Community -laœ]N
County of Los Angeles
All-Hazards Mitigation Plan
3.1 Los Angeles County Overview
Los Angeles County is the
m o s t p o p u l o u s c o u n t y i n
pUN 4_VpNL 1pApNm
encompassing a diverse
AllAy aS Ja^^q_VpVNm
]A_LmJAiNm A_L
infrastructure. According to
the most recent census
LApA !am _TN]Nm aq_py
has a population of
approximately 10 million
residents of which more than 1 million reside in unincorporated areas. The County’s LN^aTlAiUVJmTNaTlAiUVJSNApqlNmA_LNJa_a^VJAJpVvVpVNmilNm N_pIapUq_VkqN aiialpq_VpVNmA_LmVT_VœJA_pJUA]]N_TNmSalUA|AlL^VpVTApVa_i]A__V_T3UVmqiLApNL communipyilaœ]NV_pNTlApNmV_mVTUpmSla^pUN%iNlApVa_ al Area Emergency Operations Plan (OA %- A_LlNŔNJpmJUA_TNmV_iaiq]ApVa_plN_LmV_SlAmplqJpqlN LNvN]ai^N_pA_LJ]V^ApNlVm\m
The County Operational Area (OA) consists of all political subdivisions within the TNaTlAiUVJA]Iaq_LAlVNmaS!am_TN]Nmaq_pypN_Ja^iAmmNmœ vNmqiNlvVmalVA] LVmplVJpmNVTUpVmAmpNl"A_ATN^N_plNAm"m V_JalialApNLJVpVNmmJUaa] districpmA_LAiilaxV^ApN]ymiNJVA]LVmplVJpm
County of Los Angeles
All-Hazards Mitigation Plan
3.2 Geography and Land Use
1iA__V_TavNlmkqAlN
^V]Nm!am_TN]Nmaq_py
SNApqlNm LVvNlmN pNllAV_
including coastal plains
vA]]Nym ^aq_pAV_m Vm]A_Lm
and deserts. The County’s
varied geography includes
multiple microclimates that
V _ Ŕ q N _ J N V p m N x i a m q l N p a
_ApqlA] UA|AlLm mqJU Am
NAlpUkqA\Nmpmq_A^VmwV]LœlNmŔaaLmA_L]A_Lm]VLNm4lIA_A lNAmiAlpVJq]Al]ypUN VpyaS!am_TN]NmA_LVpmmqllaq_LV_T^Nplaia]VpA_lNTVa_Al NLN_mN]yiaiq]ApNL A_LUNAvV]yLNvN]aiNL_Ja_plAmplqlA]A_Lq_V_JalialApNLAlNAm often face unique vulnerabilities due to limited infrastructure and resources. Rural areas include the _TN]Nm A_L !am -ALlNm #ApVa_A] alNmpm wUVJU UAvN m^A]] Ja^^q_VpVNm JA^iTlaq_LmA_LLAyqmNAlNAm3UNlNAlNA]mapwaVm]A_LmwVpUV_pUNaq_py1A_pA ApA]V_AA_L1A_]N^N_pN3UNaq_pyA]maV_J]qLNmAmVT_VœJA_pA^aq_paSWildland Urban Interface (WUI) areas where residential and commercial development meets underdeveloped wildland with vegetative fuels. Land use within the County is equally LVvNlmNwVpUA^VxaSlNmVLN_pVA]Ja^^NlJVA]V_LqmplVA]ATlVJq]pqlA]A_LaiN_spaces.
Recent urban development in densely populated areas has increased impervious mqlSAJNm]V\NJa_JlNpNA_LAmiUA]pwUVJUlNpAV_UNApA_LJlNApNqlIA_UNApVm]A_Lm(UHI) that are much hotter than nearby rural areas3UVmiUN_a^N_a_N]NvApNmpN^iNlApqlNm especially in low-V_Ja^NJa^^q_VpVNm]AJ\V_TTlNN_miAJNmSalJaa]V_TLLVpVa_A] ]y urbanization affects stormwater management by reducing natural drainage and NxAJNlIApV_TŔaaLV_TlVm\mV_]aw-lying areas.
3UNmN plN_Lm q_LNlmJalN pUN _NNL Sal mqmpAV_AI]N i]A__V_T mplApNTVNm mqJU Am ila^apV_TTlNN_V_SlAmplqJpqlNN_UA_JV_Tmpal^wApNlmympN^mA _L^VpVTApV_TUNAp Vm]A_LmpUlaqTUplNNi]A_pV_TA_LlNŔNJpVvN^ApNlVA]m3UNaq_ py¯mLVvNlmN]A_LqmN must be carefully managed to reduce vulnerabilities while supporting economic growth and environmental sustainability.
County of Los Angeles
All-Hazards Mitigation Plan
3.3 Social Vulnerability
Social vulnerability is a crucial component to Los Angeles County’s hazard mitigation i]A__V_T3UNaq_pyVmUa^NpaALVvNlmNiaiq]ApVa_wVpULVmiA lVpVNmV_V_Ja^N UaqmV_T mpAIV]Vpy A_L AJJNmm pa lNmaqlJNmThe Los Angeles County Anti- 0AJVm^ VvNlmVpyA_L_J]qmVa_0 _VpVApVvNJlNApNLAJa^ilNUN_m VvNkqVpyxi]alNl which is a geospatial tool that explores multiple equity data points across Los Angeles County. The ARDI Equity Explorer includes variou m]AyNlmpUApvVmqA]V|NmaJVA]NkqVpy economVJaiialpq_VpyUaqmV_TA_LUa^N]Nmm_NmmUNA]pU[qmpVJNIqV] pN_vVla_^N_p and disaster recovery data. The public can access this data at ceo.lacounty.gov/ardi/tools. Maps created using data from the ARDI Equity Explorer are in Appendix A-8.
The US Centers for Disease Control and
-lNvN_pVa_ LNœ_Nm maJVA]
vulnerability as a community’s capacity to
prepare for and respond to the stress of
hazardous events ranging from natural
disasters to human caused threats. The
CDC’s Social Vulnerability Index (Figure
3.1) is designed to identify and quantify
communities experiencing social
vulnerability.
The most recent CDC Social Vulnerability
Index score from 2022 for Los Angeles
County indicated a high level of
vulnerability across four themes:
maJVaNJa_a^VJ mpApqm UaqmNUa]L
JUAlAJpNlVmpVJmlAJVA]A_LNpU_VJ^V_alVpy
mpApqmA_LUaqmV_TpyiNplA_mialpApVa_
Vulnerable populationsVLN_pVœNLSal!am_TN]Nmaq_pypUApwV]]INJa_mVLNlNLV_pUN AHMP include:
Figure 3.1 CDC Social Vulnerability Index (CDC 2022)
County of Los Angeles
All-Hazards Mitigation Plan
x Low-_Ja^N 0NmVLN_pm :
Individuals living below or near
the poverty line are often
disproportionately affected by
LVmAmpNlmLqNpa]V^VpNLœ_A_JVA]
resources for emergency
ilNiAlNL_Nmm lNmia_mN A_L
recovery.
x People with Access and
Functional Needs (AFN) :
Individuals with Access and
Functional needs have increased
challenges in ilNiAlNL_Nmm
NvAJqApVa_ mUN]pNlV_T AJJNmmV_T
emergency services and recovery.
Access and Functional Needs
include but are not limited to
people who have any combination
in varying degree of: physical
disabilities V_pN]]NJpqA] disabilities
developmental disabilities ^N_pA]
health-lN]ApNL VmmqNm vVmqA]
V^iAVl^N_pm UNAlV_T
impairments/deaf ^aIV]Vpy
impairments or chronic
conditions. AFN also include
a]LNlALq]pmV_SA_pmA_LJUV]LlN_ people ]VvV_TV_V_mpVpqpVa_A]V|NLmNppV_Tm people living below tUNiavNlpy]V_NalNxiNlVN_JV_TUa^N]Nmm_Nmmpeople with ]V^VpNL_T]VmUilaœJVN_JyalAlN_a_ -_T]VmUmiNA\Nlmal people who are transportation disadvantaged.
x People Experiencing Homelessness (PEH) : With an estimated over
individuals NxiNlVN_JV_TUa^N]Nmm_NmmpUVmiaiq]ApVa_VmiAlpVJq]Al]yApl Vm\ during extreme weather events and other disasters.
x Immigration Status : Fear of engaging with government services based on immigration status can prevent residents from accessing critical resources.
Figure 3. 3 Breakdown of Language at Home in Los Angeles County (OAEOP 2023)
Figure 3.2 ŝƐĂďŝůŝƚLJ^ƚĂƟƐƟĐƐŝŶ>ŽƐŶŐĞůĞƐŽƵŶƚLJ (OAEOP 2023) County of Los Angeles
All-Hazards Mitigation Plan
x !V^VpNL_T]VmU-laœJVN_Jy Over 40% of residents speak a language other pUA__T]VmUApUa^NUVTU]VTUpV_TpUN_NNLSal^q]pV]V_TqA]A_ LJq]pqlA]]y appropriate outreach efforts. Language accessibility is critical to ensure all residents and visitors can obtain information and services during a disaster. See Figure 3.3 for a breakdown of languages spoken at home in Los Angeles County not including American Sign Language.
3UNœTqlNIN]awUVTU]VTUpmJNlpAV_vAlVAI]NmV_!am_TN]Nmaq_pypUAp^AyV_JlNAmN vq]_NlAIV]Vpy pa N^NlTN_JVNm A_L LVmAmpNlm 3a ALLlNmm pUNmN vq]_NlAIV]VpVNm pUN County’s mitigation planning includes equitable strategies designed to reduce risk and e_UA_JNlNmV]VN_JNA^a_TpUNmNiaiq]ApVa_m3AlTNpNLaqplNAJUV^ilavNLAJJNmmpa lNmaqlJNm ilNiAlNL_Nmm NLqJApVa_ NvN_pm A_L Ja]]AIalApVa_ wVpU Ja^^q_Vpy organizations are integral to these efforts.
Figure 3.4 Los Angeles County Vulnerability Variables (OAEOP 2023) County of Los Angeles
All-Hazards Mitigation Plan
The Federal Emergency Management Agency (FEMA) maintains the National Risk _LNxA^AiiV_Tpaa]pUApAmmNmmNmiammVI]NUA|AlLmA[qlVmLVJpVa_VmmqmJNipVI]Npa in combination with the amount of loss that could result from those hazards. Los Angeles County ranks as the community with the most risk in the United States AJJalLV_TpapUN"#ApVa_A]0Vm\_LNxJJalLV_TpapUN#Ap Va_A]0Vm\_LNx UA|AlLmwVpUpUNUVTUNmplVm\Sal!am_TN]Nmaq_pyV_J]qLNNA lpUkqA\NwV]LœlNm NxplN^NUNApŔaaLV_TUVTUwV_LmA_L]A_Lm]VLNm
3.4 Economy and Critical Infrastructure
!am _TN]Nm aq_py Vm A T]aIA] NJa_a^VJ UqI UampV_T V_LqmplVNmm q J U A m N_pNlpAV_^N_ppNJU_a]aTy^A_qSAJpqlV_TA_LV_pNl_ApVa_A]plA LN3UN-alpaS!am Angeles and the Port of Long Beach collectively form one of the world’s busiest trade TApNwAym q_LNlscoring the importance of protecting critical infrastructure from hazards including those exacerbated by climate change. Critical facilities provide mNlvVJNmA_LSq_JpVa_mNmmN_pVA]paAJa^^q_VpyNmiNJVA]]yLqlV_TA_LASpNlALVmAmpNl Common types of cr VpVJA]SAJV]VpVNmV_J]qLNIqpAlN_ap]V^VpNLpaœlNmpApVa_m ia]VJN mpApVa_mUamiVpA]mmJUaa]mA_LqpV]VpVNmlVpVJA]SAJV]VpVNm^AyA]maV_J]qLNi]AJNmpUAp JA_INqmNLSalmUN]pNlV_TJaa]V_TJN_pNlmmpATV_TiqliamNm alapUNl]AlTNiqI]VJ gathering spots such as community centers and libraries. Critical facilities include those operated by non-governmental and business partners vital for redevelopment or Figure 3.5 &
DEĂƟŽŶĂůZŝƐŬ/ŶĚĞdž (2025)
County of Los Angeles
All-Hazards Mitigation Plan
N J a _ a ^ V J m N J q l V p y : U N _ p U N m N A l N A S S N J p N L I y A L V m A m p N l p U N aq_py ilavVLNm businesses and workers impacted by the disaster with vital information and resources.
This allows them to maneuver effectively through disaster response toward recovery using its network of job centers and business hubs.
Other critical infrastructure includes the facilities and industries that enable all facets of maJVNpypaSq_JpVa_V_J]qLV_TIqp_ap]V^VpNLpapUNSa]]awV_TJa^^q_Vpy]VSN]V_Nm x Safety and Security 3UN^ylVALaS]aJA]]AwN_SalJN^N_pœlNA_LlNmJqN N^NlTN_Jy^A_ATN^N_pmJUaa]mA_LapUNlTavNl_^N_pmNlvVJNmpUAp^AV_pAV_ public safety and security.
x Communications: The interconnected network of infrastructure owners and aiNlApalmaSJa^^q_VJApVa_mmympN^mmqJUAmV_pNl_NppN]NiUa_NJN]]q]AlA_L apUNlJa^^q_VJApVa_mpawNlmJAI]NmApN]]VpNA_L^alN x 3lA_mialpApVa_ #Npwal\m: The County’s extensive network of laALwAym UVTUwAymlAV]wAymplA_mVpmympN^mand airports is essential for daily operations and disaster response.
x Energy Systems: -awNlTN_NlApVa_SAJV]VpVNmN_NlTyLVmplVIqpVa__Npwal\mA_L pipelines are vulnerable to multiple types of hazards and threats. x Water and Wastewater Systems: Drought conditions and aging infrastructure at the over 220 different water agencies in Los Angeles County pose risks to water availability and quality.
x Healthcare Facilities : Over 100 hospitals and numerous clinics serve the aq_py lNkqVlV_T laIqmp Ja_pV_TN_Jy i]A_m pa ^AV_pAV_ aiNlApVa_m LqlV_T disasters.
x Food and Shelter: 3 U N v A m p m y m p N ^ a S S a a L i l a L q J p V a _ V N A T l V J q ] p q l N LVmplVIqpVa_A_LlNpAV]A]a_TwVpUJa^^q_VpyUaqmV_TalmUN]pNlV_T
3.5 Climate and Environmental Conditions
!am_TN]Nmaq_pySAJNmNmJA]ApV_TlVm\mSla^J]V^ApNJUA_TNmVT_VœJA_p]yV^iAJpV_T Vpm N_vVla_^N_p NJa_a^y A_L Ja^^q_VpVNm 3UNmN JUA]]N_TNm V_J]qLN lVmV_T pN^iNlApqlNmila]a_TNLLlaqTUpm^alNSlNkqN_pA_LmNvNlNNxplN^NwNApUNlNvN_pm and their cascading effects. These risks highlight the critical need for adaptive planning pailapNJpvq]_NlAI]Niaiq]ApVa_mV_SlAmplqJpqlNA_L_ApqlA] lNmaqlJNm NyJ]V^ApN- County of Los Angeles
All-Hazards Mitigation Plan
related considerations referenced in the Los Angeles County Climate Action Plan that will be addressed in this AHMP includeIqpAlN_ap]V^VpNLpa:
x Extreme Weather Events: Extreme temperatures in the Los Angeles region are NxiNJpNLpaV_JlNAmN
apULlyA_LwNpNxplN^NmAlNila[NJpNLpaV_pN_mVSy]NALV_T to longer dry periods than historically experienced. These dry periods are expected paINSa]]awNLIymVT_VœJA_p]ywNppNlJa_LVpVa_mV_J]qLV_TAp^ amiUNlVJlVvNlm IlV_TV_T^alNV_pN_mNlAV_SA]]3UVmiAppNl_^AylNmq]pV_V_Jl NAmNLwApNlmJAlJVpy ^qLm]VLNmA_LŔaaLV_T
x Sea-!NvN]0VmN : Coasta] J a ^ ^ q _ V p V N m A l N A p U N V T U p N _ N L l V m \ a SŔ a a L V _ T A _ L NlamVa_pUlNApN_V_TUa^NmIqmV_NmmNmA_LJlVpVJA]V_SlAmplqJpqlN Sea level rise can NxAJNlIApNpUNV^iAJpmaSUVTUpVLNmmpal^mqlTNmA_LUNAvyi lNJViVpApVa_A_L JA_]NALpaV_JlNAmNLJaAmpA]ŔaaLV_TA_LmUalN]V_NNlamVa_ x _JlNAmV_T :V]LœlN 0Vm\ ]V^ApN JUA_TN UAm V_pN_mVœNL wV]LœlN mNAma_m particularly in the County’s mountainouswV]L]A_LqlIA_V_pNlSAJN:4 and new and undeveloped regions. :V]LœlNmAlNila[NJpNLpaV_JlNAmNV_SlNkqN_JyA_L V_pN_mVpyV_J]qLV_TV_ma^NAlNAm_apUVmpalVJA]]yV^iAJpNLIywV]LœlN _lNmia_mNpUNaq_pyUAmilValVpV|NLV_pNTlApV_TJ]V^ApNALA ipApVa_mplApNTVNmV_pa VpmUA|AlL^VpVTApVa_i]A__V_TAmaqp]V_NLV_pUN]V^ApN9q]_NlAIV]VpymmNmm^N_pA_L the OAEOP .
3.6 Regional Collaboration and Planning Efforts
Los Angeles County’s size and complexity necessitates collaboration with numerous [qlVmLVJpVa_mATN_JVNmA_LJa^^q_VpyalTA_V|ApVa_m3UNaq_pyVmLNmVT_ApNLAmpUN Operational Area Coordinator and functions as an intermediate level in the State of California’s Standardized Emergency Management System (SEMS). In accordance with 1"1pUNaq_pymNlvNmAmpUNJa^^q_VJApVa_mA_LJaalLV_ApVa_ ]V_\INpwNN_]aJA] governments within Los Angeles County and the state government. Partnerships with AJALN^VJ V_mpVpqpVa_m _a_-ilaœpm A_L ilVvApN mNJpal mpA\NUa]LNlm support data Ja]]NJpVa_iqI]VJN_TATN^N_pA_LV__avApVvN^VpVTApVa_mplApNTVNmLLVpVa_A]]ypUN County has also adopted Emergency Support Functions (ESFs) as the primary emergency management coordination structure. ESFs group function- miNJVœJ stakeho]LNlmwUawV]]JaalLV_ApNpUlaqTUaqpA]]iUAmNmaSN^NlTN_Jy^A _ATN^N_p County of Los Angeles
All-Hazards Mitigation Plan
including function-miNJVœJ ^VpVTApVa_ AJpVvVpVNm al ^alN V_Sal^ApVa_ a_ lNTVa_A] N^NlTN_Jy^A_ATN^N_pJa]]AIalApVa_A_Li]A__V_TlNSNlN_JNpUNOAEOP .
3.7 Implications for Hazard Mitigation Planning
Understanding the community is a critical aspect in hazard mitigation planning. This Ja^^q_Vpyilaœ]NwV]]V_Sal^\NyJa_mVLNlApVa_mV_mqImNkqN_pmNJpVa_maSpUN"- including but not limited to the following:
x Targeted Outreach: Include vulnerable populations and the business community in the planning process through equitable public outreach. x _SlAmplqJpqlN0NmV]VN_JN -lValVpV|N pUN ilapNJpVa_ aS JlVpVJA] V_SlAmplqJpqlN V_J]qLV_TialpmA_LplA_mialpApVa__Npwal\mN_NlTymympN^mA_ LwApNlA_L wAmpNwApNlmympN^mA^a_TapUNlm
x Climate Adaptation: Develop strategies to mitigate the impacts of climate JUA_TNSaJqmV_Ta_qlIA_UNApVm]A_LmmNA-]NvN]lVmNA_LwV]LœlNlVm\m x 0NTVa_A]aalLV_ApVa_ Strengthen direct collaboration within the OA between pUNaq_py]aJA][qlVmLVJpVa_mmiNJVA]LVmplVJpmq_VœNLmJUa a] LVmplVJpmpUN business community and cross-sector non-governmental partners to enhance AwAlN_NmmilNiAlNL_NmmA_LlNmia_mNJAiAIV]Vties.
x Transparent & Open Communication: _mqlNJa^^q_VJApVa_mAlNAJJNmmVI]N and clear to advance public trust and safety. Develop dashboards to demonstrate progress.
County of Los Angeles
All-Hazards Mitigation Plan
4 Climate Change
County of Los Angeles
All-Hazards Mitigation Plan
4.1 Climate Change Overview
Climate change refers to the changing effect of the Earth's J]V^ApNmympN^avNlpV^N V_J]qLV_TJUA_TNmV_pN^iNlApqlNilNJViVpApVa_A_LwV_LiAppN l_m]V^ApNJUA_TN had mVT_VœJA_pV^iAJpma_! am_TN]Nm aq_py AS SNJpV_TvAlVaqmAmiNJpmaS]VSN N_vVla_^N_pV_SlAmplqJpqlNA_LmqmpAV_AI]NLNvN]ai^N_pA_Li lNmN_pm increasing lVm\mSla^A^i]VœNLUA|AlLmA_LJUA_TV_TIAmN]V_NmNTmNA]NvN] V_papUNSqpqlN. The lApNaSJ]V^ApNJUA_TNUAmmVT_VœJA_p]yAJJN]NlApNLavNlpUN last three decades and trends continues. This plan addresses the effects of climate change related to disasters wVpUV_pUNaq_pyA_LmplApNTVNmpa^VpVTApNlVm\mSaJqmV_Ta_ilNiAlNL_NmmlNmV]VN_JN and equity.
]V^ApNJUA_TNJa_plVIqpNmpa^alNSlNkqN_pA_LV_pN_mNLVmAmpN lmmqJUAmŔaaLm wV]LœlNmLlaqTUpA_LNxJNmmVvNUNAp0VmV_TpN^iNlApqlNmA_LJ UA_TV_TwNApUNl patterns pose UNA]pUlVm\m]V\NUNAp-lN]ApNLV]]_NmmNmlNmiVlApalyVmmqNmA_LpUNmilNAL of diseases. Hazard mitigation efforts aim to reduce the impacts and effects of greater hazards due to climate change. The economic impact of climate change has been mqImpA_pVA] ASSNJpV_T V_LqmplVNm mqJU Am ATlVJq]pqlN paqlVm^ A_L V_mqlA_JN with increasing risks due to accelerating climate changes.
Greenhouse Gas (GHG) emissions are the main driver of J]V^ApNJUA_TNwUVJUJAqmNm V_JlNAmNLSlNkqN_JyLqlApVa_A_LmNvNlVpyaSNxplN^NwNApUNl A_LJ]V^ApN -related LVmAmpNlm]V^ApNJUA_TNNxAJNlIApNmAVlia]]qpVa_]NALV_Tpa iaalAVlkqA]VpyA_L health issues. GHG emissions from lNmVLN_pVA]IqV]LV_TmJa^^NlJVA]A_L institutional SAJV]VpVNm^A_qSAJpqlV_TV_LqmplVNmA_LJa_mplqJpVa_N_NlTyV_LqmplVNm oil and natural gas systems. plA_mialpApVa_fossil N_NlTywV]LœlNmA_LapUNl sources contribute to increased particulate matter and other pollutants in the air.
County of Los Angeles
All-Hazards Mitigation Plan
4.2 _pNTlApV_T]V^ApNUA_TNV_paA|AlL-laœ]Nm
Integrating climate change into
UA|AlLilaœ]NmV_va]vNmAmmNmmV_TpUN
current and future impacts of climate
change on various hazards and
incorporating this information into
planning and mitigation strategies.
This section highlights how climate
change relates to these hazards and
how the county is addressing climate
change through hazard mitigation
efforts which help protect the county’s
residents and economies from the
adverse effects of climate changes and climate-A^i]VœNLevents.
4.2.1 Extreme Heat
Increasing temperatures and high heat events is one of the most conspicuous results of and a direct correlation between GHG pollution and climate change. Excessive pN^iNlApqlNmV_pUN!am_TN]NmlNTVa_AlNNxiNJpNLpaV_JlNAmN mVT_VœJA_p]y^alN very hot days and warm nights. In addition to increasing baseline temperatures and NxplN^NUNApLqNpaJ]V^ApNJUA_TNUNApVm]A_LmNxAJNlIApNpN^ iNlApqlNmA_LUVTU heat events. As development occurs and darker paved surfaces replace open land and vNTNpApVa_pUNmN AlNAmINJa^NwAl^NlSal^V_TA_¬Vm]A_LaSUNA p!am_TN]Nm County experiences more frequent and excessive heat due to climate change. This is currently a major risk and with unmitigated GHG emissions increasing heat will lead to even greater health issqNmV_JlNAmNLN_NlTyLN^A_LSalJaa]V_TA_LapUNlmplAV_ma_ infrastructure.
4.2.2 Flooding
]aaLV_TV_!am_TN]Nmaq_pyaJJqlmLqNpaNxplN^NlAV_SA]]N vN_pmJAqmV_TŔAmU ŔaaLmlVvNlV_NŔaaLV_TA_LV_JlNAmNLmqlSAJNwApNlaAmpA]A lNAmV_!am_TN]Nm County are vulnerable to sea- ]NvN]lVmN1!0 wUVJUNxAJNlIApNmJaAmpA]UA|AlLm]V\N ŔaaLmmpal^mqlTNmA_LJUla_VJNlamVa_%pUNllN]ApNLUA|AlLmV_J]qLNŔaaLV_T_NAl Figure 4.1 Sources of GHG Emissions from within Los Angeles County (LA County ϮϬϮϰ͖ϮϬϰϱůŝŵĂƚĞĐƟŽŶWůĂŶͿ
County of Los Angeles
All-Hazards Mitigation Plan
pUN^aqpUmaSmplNA^mA_LJUA__N]m]A_Lm]VLNmA_LmNAwApNlwN ]]V_plqmVa_1!0 NxAJNlIApNmpUNV^iAJpmaSUVTUpVLNmmpal^mqlTNmA_LUNAvyilNJViVpApVa_ŔaaLV_T and continued SLR will lead to more life safety concerns and increased damage to property and infrastructure.
4.2.3 Drought
- l a ] a _ T N L L l a q T U p m U A v N I N J a ^ N ^ a l N J a ^ ^ a _ A S S N J p V _ T p U N w A p N lm q i i ] y A T l V J q ] p q l N A _ L N J a m y m p N ^ m a S ! a m _ T N ] N m a q _ p y l y A _ L w N p NxplN^Nm AlN projected to increase and are likely to cause drier periods than what the region has historically experienced.
1aqpUNl_A]VSal_VAila[NJpNLpaTNpLlVNlwUV]N#alpUNl_A]V Sal_VAwV]]V_JlNAmNV_ temperature. This will result in loss of snowpack within the Sierra Nevada Mountain lA_TN^NA_V_T]NmmwApNlSalA]]A]VSal_VA_mV_J]qLV_TSAl^NlmlNmVLN_pmA_LqpV]ities.
The State Water Resource Control Board proclaimed several water conservation N^NlTN_JylNTq]ApVa_mLqNpamNvNlNLlaqTUpJa_LVpVa_mpUAplNk qVlNmJa^^NlJVA] V_LqmplVA]A_LlNmVLN_pVA]Ja_mNlvApVa_NSSalpm-laJ]A^ApVa_mV_J]qLN x January 4, 2022: State Water Board adopted the prohibited wasteful water uses emergency regulation
x May 24, 2022: the State Water Board adopted the emergency regulation to ban decorative grass watering like non-functional turf irrigation x December 7, 2022: the State Water Board readopted the prohibited wAmpNSq]wApNlqmNmN^NlTN_JylNTq]ApVa_
x May 26, 2023: the State Water Board readopted the emergency regulation to ban decorative grass watering.
4.2.4:V]LœlN
wV]LœlNVmA_q_i]A__NLA_Lq_Ja_pla]]NLœlNV_A_AlNAaSJa^IqmpVI]NvNTNpApVa_ 3UNmNœlNmJA_NAmV]ymilNALINya_LpUN_ApqlA]AlNAmilV^AlV]y V_va]vV_TA_LUAvNA iapN_pVA]paJAqmNLA^ATNmaqpmVLNaSpUNiNlV^NpNl:V]LœlNilaIAIV]VpyLNiN_Lman ]aJA]wNApUNlJa_LVpVa_maqpLaalAJpVvVpVNmA_LA_yilNJNLV_TJa_LVpVa_mNT]apmaS lAV_]NALV_TpavNTNpApVa_TlawpUA_LpUN_LlyV_TJa_LVpVa_m A_LAiapN_pVA]VT_VpVa_ NT]VTUp_V_TmplV\NAlma_LNIlVmIql_V_TN]NJplVJA]NkqV i^N_pSAV]qlNJAlpAV]iViN N p J 3 U N S l N k q N _ J y A _ L V _ p N _ m V p y a S w V ] L œ l N m U A m V _ J l N A m N L L lVvN_ Iy UVTUNl County of Los Angeles
All-Hazards Mitigation Plan
pN^iNlApqlNm]awNlilNJViVpApVa_]awNllN]ApVvNUq^VLVpyA_L ila]a_TNLLlaqTUpm 3UNmN NvN_pm UAvN JAqmNL ]amm aS ]VSN LNmplay A_Lal LA^ATN pai l a i N l p y V_SlAmplqJpqlNpUNN_vVla_^N_pA_LiamNTlNApNllVm\mLqNpaU VmpalVJA]LNvN]ai^N_p patterns. The pV^N]V_NaS^A[alwV]LœlNNvN_pmA_LAJlNATNIql_NLV_!am_TN ]Nm County is listed at Section 6.2 of the plan.
4.3 Climate Mitigation Strategies
Los Angeles County is actively addressing climate change and implementing hazard mitigation strategies to reduce its impacts and build long-term resilience. The County SAJNmV_JlNAmV_TlVm\mSla^NxJNmmVvNUNApwV]LœlNmLlaqTUpmŔaaLmA_LmNA-level rVmN A]]aSwUVJUpUlNApN_Ja^^q_VpVNmV_SlAmplqJpqlNA_L_ApqlA]lNmaqlJNm 3aALLlNmm^A_yaSpUNmNJUA]]N_TNmpUNaq_pyUAmLNvN]aiNLJ a^ilNUN_mVvN J]V^ApNi]A_mA_LmplApNTVNmpUApV_pNTlApNJ]V^ApNALAipApVa_ mqmpAV_AI]N]A_LqmN N^NlTN_JyilNiAlNL_Nmm A_LN_vVla_^N_pA]Ja_mNlvApVa_ yN_SalJV_TIqV]LV_T
JaLNmV_vNmpV_T V_TlNN_V_SlAmplqJpqlNA_LmplN_TpUN_V_TJa^^q_VpyilNiAlNL_Nmm Los Angeles County aims to minimize risks and enhance disaster resilience. These efforts align with state and federal climate policies and are designed to protect both current and future generations while encouraging a more sustainable and livable environment for all.
4.3.1 Climate Resilience Plans and Actions
x Los Angeles County 2045 Climate Action Plan (2045 CAP): Establishes aggressive targets to reduce greenhouse gas emissions and achieve carbon neutrality by 2045.
x :ApNla_mNlvApVa_ËlaqTUp0NmV]VN_JN"NAmqlNm Implements mandatory wApNllNmplVJpVa_mila^apNmlAV_wApNlUAlvNmpV_TA_LNxiA_Lm Tlaq_LwApNl recharge and water recycling projects.
x :V]LœlN"VpVTApVa_Ë9NTNpApVa_"A_ATN^N_p-laTlA^m Enforces Wildland 4lIA__pNlSAJN:4 JaLNmV_JlNAmNmSalNmp^A_ATN^N_ppNJU_VkqNmaligned with Traditional Ecological Knowledge (TEK) principles and practices of our native indigenous communities A_LmplN_TpUN_mœlN -resistant building and landscape requirements.
County of Los Angeles
All-Hazards Mitigation Plan
x lNN__SlAmplqJpqlNË4lIA_aa]V_T_VpVApVvNm Expands tree planting aligned with TEK principles and practices V_vNmpVTApNmlN^avV_TUAlLiAvNL mqlSAJNm A_L i]A_pV_T Tlaq_LJavNl qpV]V|Nm A_L ila^apNm iqI]VJ Jaa]V_T JN_pNlmA_LUa^NUNApilNiAlNL_NmmA_LN_JaqlATNmpUNqmNaSl NŔNJpVvN ¬Jaa]laaœ_TA_LmqlSAJNmpa^VpVTApNpUNqlIA_UNApVm]A_L4 NSSNJt. x Heat Action Plan: Develops strategies to reduce the adverse health impacts of NxJNmmVvNUNAppUlaqTUiqI]VJmUALNmplqJpqlNmJaa]V_TJN_pNlmIqV]LV_TJaLNm and increased public awareness campaigns for all susceptible to extreme heat. 3UNmNmplApNTVJAJpVa_mlNŔNJp!am_TN]Nmaq_py¯mJa^^Vp^N_p papAJ\]V_TJ]V^ApN JUA_TN
yV_pNTlApV_TilaAJpVvNia]VJVNmindigenous-V_Sal^NLilAJpVJNmcommunity- LlVvN_ma]qpVa_mA_LlNmV]VN_pV_SlAmplqJpqlN!am_TN]Nmaq_pyVm_apa_]y^VpVTApV_T current risks but also preparing for a future where communities can thrive in an ever- changing dynamic environment.
4.4 Climate Change Conclusion
3UlaqTUilaAJpVvNia]VJVNmA_LJa^^q_VpyN_TATN^N_p!am_TN]N maq_pymplVvNm pa _AvVTApN pUN Ja^i]NxVpVNm aS A JUA_TV_T J]V^ApN A_L mASNTqAlL Vpm iNai]N N_vVla_^N_pV_SlAmplqJpqlNA_LNJa_a^VNm3UVmAiilaAJUUN]im^V_V^V|NpUNlVm\mA_L impacts associated with climate-related hazards. Addressing climate change in hazard ^VpVTApVa_UN]iN_UA_JNmASNlUNA]pUVNlA_L^alNmqmpAV_AI]NJa^^q_VpVNm
County of Los Angeles
All-Hazards Mitigation Plan
5 Integrating Access and
Functional Needs (AFN)
into Hazard Mitigation
County of Los Angeles
All-Hazards Mitigation Plan
5.1 AFN Introduction
Modern hazard mitigation planning increasingly recognizes that resilient communities must address the needs of all residents —inc luding those with access and functional _NNLm# VmpalVJA]]yV_LVvVLqA]mwVpULVmAIV]VpVNm VNV_J]qLV_TIqp_ap]V^VpNLpa yaqpU pUamN NJa_a^VJA]]y LNilNmmNL ilNT_A_p NpJ JUla_VJ UNA]pU Ja_LVpVa_m ]A_TqATNIAllVNlmalplA_mialpApVa_LVmALvA_pATNmUAvN been underrepresented in emergency planning. As evidenced by the best practices for stakeholder inclusion and furpUNl mqiialpNL Iy _ApVa_A] ilNiAlNL_Nmm SlA^Nwal\m V_pNTlApV_T # considerations leads to plans that are mo re inclusive and effective. By proactively N_TATV_T#iaiq]ApVa_mA_LmqiialpATN_JVNmV_NvNlyiUAmNS la^preparedness pUlaqTUlNJavNlyAUA|AlL^VpVTApVa_i]A_JA_lNLqJN]ammNmV^ilavNNvAJqApVa_A_L mUN]pNlV_TaqpJa^NmA_LIqV]LplqmpINpwNN_N^NlTN_Jy^A_ATN^N_pATN_JVNmA_L the communities they serve.
5.2 Inclusion of AFN and Vulnerable Populations in Planning ^A[alJa^ia_N_paSNSSNJpVvN^VpVTApVa_i]A__V_TVmA¬wUa]NJa^^q_VpyAiilaAJU Incorporating AFN voices into the planning process is crucial because these stakeholders offer real-world insights into the challenges they face during emergencies. Key stNimpapUVmilaJNmmV_J]qLNIqpAlN_ap]V^VpNLpa x 1pA\NUa]LNl _TATN^N_p Ensure that representatives from disability ALvaJAJyTlaqimJa^^q_Vpy-IAmNLalTA_V|ApVa_mA_LmNlvVJNilavVLNlmmqJU as local health departments and transportation agencies) are engaged early in pUNi]A__V_TilaJNmm3UNVlœlmpUA_LNxiNlVN_JNmUN]iVLentify practical barriers that might otherwise be overlooked.
x Public Participation: _JalialApV_T iqI]VJ mpA\NUa]LNlm pUlaqTU ^NNpV_Tm mqlvNymA_LapUNlaqplNAJUpaJAipqlNpUNLVvNlmN_NNLmaS# iaiq]ApVa_m This input is vital to overcoming historical marginalization and ensuring that mitigation actions are relevant and equitable to the entire population. x Ongoing Interagency Collaboration: Develop a hazard mitigation planning advisory committee and interagency working groups that include AFN stakeholders. These groups can guide both the planning process and the review aSNxVmpV_Ti]A_mN_mqlV_TpUAp#VmmqNmAlNSq]]yV_pNTlApNLSla^pUN outset.
County of Los Angeles
All-Hazards Mitigation Plan
5.2.1 Integrating AFN into the Overall AHMP
Integrating AFN considerations is not a stand- A]a_N pAm\ Vp ^qmp IN V_pNl]AJNL throughout the entire hazard mitigation planning process. This includes:
x 0Vm\mmNmm^N_pm Incorporate AFN data into all risk assessments to ensure that pUNmiNJVœJvq]_NlAIV]VpVNmaSpUNmNiaiq]ApVa_mAlNlNŔNJpNLV_UA|AlL^AimA_L vulnerability index data.
x Mitigation Strategy Development: Ensure that every mitigation action is NxA^V_NLSalVpmV^iAJpa_#iaiq]ApVa_malNxA^i]NwUN_i ]A__V_TSal ŔaaLJa_pla]alwV]LœlNilNvN_pVa_ila[NJpmlNvVNwUawpUNmNi la[NJpmJA_IN improved to meet the needs of people with access and functional needs. x -]A_0NvVNwA_L4iLApN Ensure planning processes include regular AFN review and updates. Includes but not limited to:
o Surveys of community needs
o Consultations with AFN advisory groups
o Integration of new technological or infrastructural solutions x q_LV_T A_L 0NmaqlJN ]]aJApVa_Clearly identify funding streams and resource commitments for AFN- miNJVœJila[NJpm3UVmJaq]LV_va]vNpAlTNpNL TlA_pmSla^SNLNlA]ilaTlA^mNTA|AlL"VpVTApVa_mmVmpA_JN mpApNSq_LV_T LNLVJApNLpaAJJNmmVI]NV_SlAmplqJpqlNV^ilavN^N_pmA_L]aJA l resources such as the Productivity Investment Fund that can be accessed to improve the NSSNJpVvN_NmmA_LNSœJVN_JyaSaq_pyaiNlApVa_m
5.3 Assessment of AFN Needs
Understanding the specific needs of AFN populations requires both quantitative and qualitative approaches:
x ApAa]]NJpVa_A_L0Vm\mmNmm^N_p Use existing resourcesJa^^q_Vpy mqlvNym outreach and risk assessments to help identify the number and types of individuals with AFN at the local community level. Evaluate the regional TNaTlAiUVJLVmplVIqpVa_vq]_NlAIV]VpVNmA_LmiNJVSVJlNkqVlN^N_pmbefore and after emergencies.
County of Los Angeles
All-Hazards Mitigation Plan
x lA^Nwal\mSal_A]ymVm Adopt structured methodologies such as C-MIST a^^q_VJApVa_"AV_pAV_V_TNA]pU_LNiN_LN_JN1qiialp1ASNpyA_L Transportation) to assess/ document AFN requirements.
x C-MIST Explanation
o Communication_LVvVLqA]mwVpUUNAlV_TvVmVa_JaT_VpVvNalmiNNJU limitations may require alternative communication methods to receive or express information during emergencies.
o Medical / Health Needs: People with complex medical conditions rely a_^NLVJApVa_m^NLVJA]NkqVi^N_palmiNJVA]V|NLJAlNpa^AV_pAV_ their health and prevent complications.
o Independence3UamNwUaqmN^aIV]VpyLNvVJNmAmmVmpVvNpNJU_a]aTy or service animals need uninterrupted access to maintain their independence and daily functions.
o Supervision & Safety: Some individuals require continuous support for mASNpyJa^SalpalN^apVa_A]wN]]-INV_TV_J]qLV_TpUamNwVpU^N^aly VmmqNmimyJUVAplVJJa_LVpVa_malV_pN]]NJpqA]LVmAIV]VpVNm o Transportation: Individuals without personal transportation or with ^aIV]Vpy]V^VpApVa_m_NNLAJJNmmVI]NA_LlN]VAI]NaipVa_mNmiNJVA]]yV_ emergencies and evacuations.
x _pNTlApV_T9q]_NlAIV]VpymmNmm^N_pm Leverage tools from local climate vulnerability assessments and hazard mitigation plan reviews to identify areas where AFN populations overlap with high-lVm\|a_NmNTS]aaLi]AV_m
County of Los Angeles
All-Hazards Mitigation Plan
wildfire-prone areas). This integration helps prioritize mitigation actions in regions where vulnerable populations are most exposed.
5.4 Coordination with AFN Support Agencies
Effective mitigation planning requires robust coordination with both governmental and nongovernmental agencies that serve AFN populations. Best practices include:
x Formal Partnerships: Establish relationships and partnerships with agencies mqJUAmiqI]VJUNA]pULNiAlp^N_pmmaJVA]mNlvVJNmplA_mialpAp Va_AqpUalVpVNm community-IAmNLalTA_V|ApVa_mA_LLVmAIV]VpyALvaJAJyalTA_V|ApVa_m3UN mN iAlp_NlmUVimN_mqlNpUAppUNlNVmJ]NAla_T oing communication and that roles A_LlNmia_mVIV]VpVNmAlNLN]V_NApNLINSalNLqlV_TA_LASpNlLVmAmpNlm x Joint Training and Exercises: a_LqJplNTq]Al[aV_p^NNpV_TmA_LNxNlJVmNm that include AFN components and identify additional resources to support the needs of the AFN community. These actions will help prepare all stakeholders to work together during a crisis and help identify gaps in current plans. x Outreach and Information Dissemination: _mqlNpUApA]]V_Sal^ApVa_IapU pre-V_JVLN_pilNiAlNL_Nmm^NmmATNmlNmia_mN^NAmqlNmA_Liamp -incident recovery plans are accessible to all audiences. This includes using multiple ]A_TqATNm vAlVaqm Ja^^q_VJApVa_ Sal^Apm NT ]AlTN-ilV_p AqLVa mVT_- ]A_TqATNA_LLVTVpA]Sal^Apm A_LJq]pqlA]]yAiilailVApN^NmmATV_TpalNAJUA]] segments of the community.
5.5 AFN Conclusion
UA|AlL^VpVTApVa_i]A_IqV]LmASaq_LApVa_SalAlNmV]VN_pV _J]qmVvNJa^^q_Vpy y
ensuring that AFN and other vulnerable populations are included in every phase of i ] A _ _ V _ T S l a ^ V _ V p V A ] m p A \ N U a ] L N l N _ T A T N ^ N _ p p a p U N L N v N ] a i ^ N _p aS pAV]alNL mitigation AJpVa_mA_LJaalLV_ApNLlNmia_mNmplApNTVNmJa^^q_VpVNmJA_^V _V^V|N disaster impacts and foster long-term resilience. Drawing on best practices from _ApVa_A]SlA^Nwal\mA_L]aJA]i]A__V_TTqVLNmA_LIyV^i]N^N_pV_T-compliant shelter operations emergency managers can create a plan that truly serves every member of the community. This inclusive approach not only saves lives and property during disasters but also strengthens community trust and the overall effectiveness of emergency management efforts.
County of Los Angeles
All-Hazards Mitigation Plan
6A|AlLLN_pVœJApVa_A_L
Risk Assessment
County of Los Angeles
All-Hazards Mitigation Plan
6.1 A|AlLLN_pVœJApVa_%vNlvVNw
3UNUA|AlLVLN_pVœJApVa_A_LlVm\AmmNmm^N_pilaJNmm provide a foundation for Los _TN]Nmaq_py¯ mUA|AlL^VpVTApVa_i]A__V_TNSSalpmIyVLN_pVSy V_Tilaœ]V_TA_L AmmNmmV_TpUNlVm\mAmmaJVApNLwVpU_ApqlA]pNJU_a]aTVJA]A_LUq^A_-caused hazards.
This section builds on the framework established in the 2020 Haza lL"VpVTApVa_-]A_ incorporating insights from the 2023 Operational Area Emergency Operations Plan (OA%- pUN4 Los Angeles 3UlNApA_LA|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p (THIRA) pUN Los Angeles County Climate Vulnerability Assessment the State of A]VSal_VAA|AlL"VpVTApVa_-]A_1"- and the Federal Emergency Management Agency (FEMA) National Risk Index.
Based on these sources hazards were included and addressed in the 2025 AHMP AJJalLV_TpapUNVlSlNkqN_JymNvNlVpyA_LV^iAJppa!am_TN]N maq_pymNNIN]aw Table 6-1. Hazards that did not meet the threshold of moderate risk will not be prioritized within the plan. LLVpVa_A]]ypUlNN_Nw_ApqlA]UA|AlLm xplN^NNAp laqTUpA_L1NvNlN:V_L3al_ALa and four human-caused hazards "Amm9Va]N_JN yINl_JVLN_pm3lA_mialpApVa__JVLN_pmA_L-qI]VJNA]pU^NlTN_JVNm are included in the 2025 AHMP .
Table 6-1 Hazard Inclusion/ Omission
Hazard Comment
Earthquake Hazard is included in the plan due to its high SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
:V]LœlN Hazard is included in the plan due to its high SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Heat Wave Hazard is included in the plan due to its high SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Tornado Hazard is included in the plan due to its high SlNkqN_Jy mNvNlVpy A_L V^iAJp pa !am _TN]Nm aq_py Tornado is incorporated with the Severe Wind/ Tornado hazard ilaœ]N.
Land Movement Hazard is included in the plan due to its high SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
County of Los Angeles
All-Hazards Mitigation Plan
Hazard Comment
Lightning Hazard is included in the plan due to its high SlNkqN_Jy mNvNlVpy A_L V^iAJp pa !am_TN]Nm aq_py Lightening is incorporated wVpUpUN:V]LœlNand Flooding hazard ilaœ]Nm.
Flooding Haz AlLVmV_J]qLNLV_pUNi]A_LqNpaVpmSlNkqN_JymNvNlVpyA_L impact to Los Angeles County. 3UN]aaLV_TUA|AlLilaœ]N incorporates both Riverine and Coastal Flooding.
Drought Haz AlLVmV_J]qLNLV_pUNi]A_LqNpaVpmSlNkqN_JymNvNlVpyA_L impact to Los Angeles County.
Strong Wind Hazard is included in the i]A_LqNpaVpmSlNkqN_JymNvNlVpyA_L impact to Los Angeles County. Strong Wind is incorporated with the Severe Wind and 3al_ALaUA|AlLilaœ]N
Tsunami Haz AlLVmV_J]qLNLV_pUNi]A_LqNpaVpmSlNkqN_JymNvNlVpyA_L impact to Los Angeles County.
Winter Weather Hazard is omitted from the plan due to its minimal SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Hail Hazard is omitted from the plan due to its minimal SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Avalanche Hazard is omitted from the plan due to its minimal SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Cold Wave Hazard is omitted from the plan due to its lack of SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Hurricane Hazard is omitted from the plan due to its lack of SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Ice Storm Hazard is omitted from the plan due to its lack of SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
Volcanic Activity Hazard is omitted from the plan due to its lack of SlNkqN_Jy mNvNlVpyA_LV^iAJppa!am_TN]Nmaq_py
County of Los Angeles
All-Hazards Mitigation Plan
!am_TN]Nmaq_pySAJNmAwVLNlA_TNaSUA|AlLmLqNpaVpmTNa TlAiUVJLVvNlmVpy iaiq]ApVa_LN_mVpyA_LNJa_a^VJmVT_VœJA_JN3UNSa]]awV_TUA|AlLmwNlNVLN_pVœNL A_LilValVpV|NLSla^pUNilNvVaqm]y^N_pVa_NLmaqlJNmIAmNLa_UVmpalVJA]aJJqllN_JNm popN_pVA]V^iAJpmA_LSqpqlNlVm\m
1. :V]LœlN
2. Earthquake
3. Extreme Heat
4. Drought
5. Flooding
6. Dam Failure
7. Land Movement
8. Tsunami
9. Severe Wind and Tornado
10. Mass Violence
11. Cybersecurity Incidents
12. Transportation Incidents
13. Public Health Emergencies
^a_TpUNmNUA|AlLm six wNlNVLN_pVœNLpaINiapN_pVA]]yNxAJNlIApNLIyJ]V^ApN change V_J]qLV_TwV]LœlNNxplN^NUNApLlaqTUpŔaaLV_T]A_L^avN^N_pA_LmNvNlN wind and tornadoes. Additional human-caused hazards were included based on the 30V_J]qLV_T^AmmvVa]N_JNJyINlmNJqlVpyV_JVLN_pmplA_mialpApVa_V_JVLN_pm and public health emergencies. The results of the public Personal Disaster Impact 1qlvNyvA]VLApNLpUAppUNmNUA|AlLmAlNaSmVT_VœJA_pJa_JNl_paJaq_pylNmVLN_pmA risk assessment table comparing hazards to critical infrastructure is in Appendix C.
Table 6-2 UA_TNmV_NvN]ai^N_pA_L9q]_NlAIV]Vpy
Hazard Change (Increase/ Decrease) 0NAma_
Earthquake No Change While new construction adheres to
modern seismic codes aging
infrastructure in high seismic zones
remain vulnerable. Continued
population growth in older
neighborhoods with limited
County of Los Angeles
All-Hazards Mitigation Plan
Hazard Change (Increase/ Decrease) 0NAma_
lNplaœppV_TV_JlNAmNmavNlA]]
exposure.
:V]LœlN
(Lightning)
Increase in Vulnerability Urban expansion into Wildland- Urban Interface (WUI) areas has
increased the number of homes at
risk. Post 2020 development in
UVTUœlNmNvNlVpy|a_NmUAm
Ja_pV_qNLpUaqTULNSN_mVI]N
miAJNlNTq]ApVa_mA_L_NwœlN-
safe planning are improving
resilience for new builds.
Extreme Heat Increase in Vulnerability -aiq]ApVa_LN_mVpyurban heat islands and development in inland
valleys increases exposure. Older
multi-family units without air
conditioning remain a concern.
More outdoor workers and people
experiencing homelessness (PEH)
add to vulnerable population.
Land
Movement
Stable to Slight Increase Most new development avoids
known landslide-prone areas due
to zoning and geotechnical review.
awNvNl climate-driven
precipitation variability and
wV]LœlNmJa_pV_qNpaLNmpAIV]V|N
slopes in developed areas.
Flooding
(Lightning)
Increase in Vulnerability New impervious surfaces from
development increase stormwater
lq_aSS%]LNlŔaaLJa_pla]
infrastructure is strained under
UNAvVNl^alNSlNkqN_plAV_NvN_pm.
County of Los Angeles
All-Hazards Mitigation Plan
Hazard Change (Increase/ Decrease) 0NAma_
Drought Increase in Vulnerability Continued population growth and water demand in arid and semi-
arid zones has outpaced gains in
conservation. Agricultural
vulnerability persists in high desert
areas.
Severe Wind
and Tornado
Increase in Vulnerability Los Angeles County is
experiencing more frequent and
V_pN_mNwV_LNvN_pmV_J]qLV_T
tornadoes. As urban development
NxiA_LmplNNJA_aiVNmA_L
overhead utilities in densely
developed areas continue to
contribute to cascading hazards. In
lNmia_mNNSSalpmAlNq_LNlwAypa
underground utility lines in high-
risk areas.
Tsunami Stable Revised tsunami inundation maps
UAvNlNœ_NLpUNAp-risk zones. New
developments in coastal areas are
largely outside the updated hazard
areas or comply with stricter
coastal building codes.
Dam Failure Stable/ Slight Increase While no new major dams have INN_Ja_mplqJpNLV_lNJN_pyNAlm
downstream development
continues to increase population
and critical infrastructure exposure
within inundation zones.
County of Los Angeles
All-Hazards Mitigation Plan
Countytytytyyyytyyyyyyyyyyyyyyyyyy ooofofofofooofofoffofofofoooofooffoofofoffooffofofofooffofffofffoooooooofooooooofooooooooooooooooooooooooooooooofooooooooooooooooooooo LoLos As Angengelesles AllAAllAAAAAAAAAAA
-
HazHaazHazazazazazazzzazazzzHazazzzaazazazaazazzzzzzazzzazaazaazzaaaaaaa aarararardardrdrdaarardardrdarardardardardararararaaaardrrardrdrrrrrrrrrddrrrrrrrr ss Ms ititigatgationon PlaPlan
6.2 :V]LœlN
6.2.1 Nature
: V ] L œ l N m A l N S A m p-^avV_T q_Ja_pla]]NL
œlNmpUApJa_mq^NvNTNpApVa_A_LlAiVL]y
milNALaSpN_pUlNApN_V_T]VvNmmplqJpqlNm
A_L V_SlAmplqJpqlN 3UNmN œlNm JA_ IN
VT_VpNL Iy _ApqlA] JAqmNm mqJU Am
]VTUp_V_TalUq^A_AJpVvVpVNmV_J]qLV_T
unattended ca ^iœlNm Law_NL iawNl
]V_NmA_LAlma_3UNV_JlNAmV_TSlNkqN_Jy
LqlApVa_A_LV_pN_mVpyaSwV]LœlNmV_!am
Angeles County are possibly linked to the
JUA_TV_T J]V^ApN wVpU UappNl
pN^iNlApqlNmila]a_TNLLlaqTUpmA_L
reduced humidity levels making the
rNTVa_UVTU]ymqmJNipVI]NpaœlNm
AJpalm_ŔqN_JV_T:V]LœlN
NUAvVal
x Topography: Fires spread
more rapidly on steep slopes
and are often driven by the
Santa Ana winds.
x Fuel LoadN_mNLly
vegetation and high tree mortality increase fire intensity. x Weather ConditionsVTUpN^iNlApqlNmmpla_TwV_LmA_L]awUq^VLVpy N]NvApNSVlNlVm\wVpUpUNJUA_TV_TJ]V^ApNJa_plVIqpV_TpaA]N_TpUN_NLSVlN season.
County of Los Angeles
All-Hazards Mitigation Plan
:V]LœlNmA]maJlNApNmNJa_LAlyUA|AlLmmqJUAmiaalAVlkqA]Vpy ]A_Lm]VLNmŔaaLV_T A_LLNIlVmŔawm —especially in areas with recent burn scars where vegetation loss increases soil instability.
6.2.2 Location
!am_TN]Nmaq_pyVma_NaSpUN^ampwV]LœlN -prone regions in the United States.
B a s e d o n t h e D e p a r t m e n t o f F o r e s t r y a n d F i r e P r o t e c t i o n ( C A L F I R E ) F i r e H a z a r d 1NvNlVpy ?a_N 1? ^Aim mVT_VœJA_p wV]LœlN lVm\ NxVmpm V_ pUN 1A_pA "a_VJA "aq_pAV_m1A_AIlVN]"aq_pAV_m-A]am9NlLNmV]]mA_LPuente Hills. The 2024 THIRA and Los Angeles County Climate Vulnerability Assessment identify an increasing risk to communities located in or near these high-risk areas.
!am_TN]Nmaq_pyUAmpUlNNilV^AlywV]LœlN^A_ATN^N_p|a_Nm x NLNlA]0Nmia_mVIV]VpylNAm0m Lands administered or controlled by the federal government where federal agencies have administrative and protection responsibility for wildfires.
x 1pApN0Nmia_mVIV]VpylNAm10m Wildland areas where CAL FIRE is responsible for suppression efforts.
x !aJA]0Nmia_mVIV]VpylNAm!0m Developed regions where local ATN_JVNmmqJUAm!am_TN]Nmaq_pyVlNNiAlp^N_p!a ilavVLN fire protection.
alAINppNlvVmqA]lNilNmN_pApVa_aSpUVm:V]LœlNA|AlLwVpUV_pUN!aq_pyi]A__V_T AlNAi]NAmNlNSNlN_JNiiN_LVx_J]qLNLV_iiN_LVxAlNm NvNlA]VlNA|AlL Severity Zone maps for reference.
6.2.3 Extent
JJalLV_Tpa!0¯mVlNA|AlL1NvNlVpy?a_N1? ^Aim !am_TN]Nmaq_py contains:
x 386.06 square miles (8.11%) classified as Very High Fire Hazard Severity ?a_N1? V_!aJA]0Nmia_mVIV]VpylNAm!0m
x 625.01 square miles (13.13%) classified as Very High (FHSZ) in State 0Nmia_mVIV]VpylNAm10m.
:V]LœlNmiamNAmVT_VœJA_ppUlNAp_apa_]ypUlaqTUpUNV^^NLVApNLA^ATNpUNyJAqmN pa]VvNmilaiNlpyA_L_ApqlA]lNmaqlJNmIqpA]mapUlaqTUpUNmNJa_LAlyUA|AlLmpUAp Ja_pV_qNASpNlpUNŔA^NmAlNNxpV_TqVmUNL
_pUNASpNl^ApUaSAœlNJa^^q_VpVNmaSpN_SAJNV_JlNAmNLlVm\maSŔAmUŔaaLmLNIlVm ŔawmA_LLNTlALNLAVlkqA]Vpy3UNmNiamp -œlNV^iAJpmJA_Ja^iaq_LpUNV_VpVA] LNmplqJpVa_i]AJV_TALLVpVa_A]mplAV_a_V_SlAmplqJpqlNUNA]p UmympN^mA_LlNJav ery efforts.
County of Los Angeles
All-Hazards Mitigation Plan
6.2.4 History
!am _TN]Nm aq_py UAm NxiNlVN_JNL _q^Nlaqm LNvAmpApV_T wV]LœlNm V_ lNJN_p LNJALNmV_J]qLV_T
x Canyon Fire (1968) –
ql_NLAJlNmLNmplayNLUa^NmA_L]NL
to mass evacuations.
x Old Topanga Fire (1993) – a_mq^NL
AJlNmLNmplayV_T
structures and causing three fatalities.
x Sayre Fire (2008) – NmplayNLmplqJpqlNmV_J]qLV_TavNl^aIV]N homes.
x Station Fire (2009) – 3UN]AlTNmpSVlNV_!am_TN]Nmaq_pyUVmpaly Iql_V_T
AJlNmLNmplayV_TmplqJpqlNmA_LJAqmV_Tpwa
firefighter fatalities.
x Woolsey Fire (2018) –
ql_NLAJlNmLNmplayNLmplqJpqlNm
and resulted in three fatalities.
x Bobcat Fire (2020) – 1JalJUNL
AJlNmLNmplayV_TmplqJpqlNm
and damaging numerous infrastructures in the Angeles National Forest. x Palisades Fire (2025) – 0Nmq]pNLV_mVT_VSVJA_pLNmplqJpVa_A_L]ammaS]VSN Iql_V_TAJlNmLNmplayNLAiilaxV^ApN]ymplqJpqlNmA_L causing 12 civilian fatalities.
x Eaton Fire (2025) – 0Nmq]pNLV_mVT_VSVJA_pLNmplqJpVa_A_L]ammaS]VSN Iql_V_TAJlNmLNmplayV_TAiilaxV^ApN]ymplqJpqlNmA_L causing 17 civilian fatalities.
3UNmNœlNmUVTU]VTUppUNV_JlNAmV_TSlNkqN_JyA_LV_pN_mVpyaS wV]LœlNmN^iUAmV|V_T the urgent need for stronger mitigation and preparedness efforts. 3UN!am_TN]Nmaq_pyAlNAUAmNxiNlVN_JNLSNLNlA]]yLNJ]AlNL wV]LœlNmA_LAlN shown in the table below. 3UNlNUAvNINN__ampApNilaJ]A^ApVa_mSalwV]LœlNmV_pUN ]AmpœvNyNAlm
NLNlA]]yNJ]AlNL:V]LœlNVlN"A_ATN^N_pmmVmpA_JNNJ]AlApVa_V_!amAngeles County from 1/1/2020 to 3/28/2025
Date Incident Name No. Category
1/8/2025 A]VSal_VA:V]LœlNmA_L
Winds
4856 Federal Declaration
1/8/2025 California Eaton Fire 5550 Fire Management Assistance Declaration 1/8/2025 California Hurst Fire 5551 Fire Management Assistance Declaration 1/7/2025 California Palisades Fire 5549 Fire Management Assistance Declaration 12/10/2024 California Franklin Fire 5548 Fire Management Assistance Declaration 9/11/2024 California Bridge Fire 5537 Fire Management Assistance Declaration 10/16/2020 A]VSal_VA:V]LœlNm 4569 Federal Declaration 9/13/2020 California Bobcat Fire 5374 Fire Management Assistance Declaration County of Los Angeles
All-Hazards Mitigation Plan
6.2.5 Probability
:VpUmNvNlA]TqAlA_pNNLwV]LœlNmNAJUyNAlpUNilaIAIV]VpyaS wV]LœlNVT_VpVa_V_!am _TN]Nmaq_pyVmTlALqA]]yV_JlNAmV_TLlVvN_]AlTN]yIyJ]V^A pNJUA_TN There is a ÈJUA_JNaSAœlNaJJqllV_TNAJUyNAlwVpUV_pUNTNaTlAiUVJ i]A__V_TAlNA VmpalVJA]]ywV]LœlNmaJJqllNLINpwNN_ q_NA_L#avN^INlIqp lNJN_pyNAlmUAvN shown a year- laq_LœlNmNAma_LqNpaUappNlLlVNlJa_LVpVa_mA_L^alNV_pN_ mN weather variability.
!a_TNlLlyiNlVaLmlNLqJNLUq^VLVpyA_LV_JlNAmNLpN^iNlApqlN mJaqi]NLwVpU historic drought and vegetation die- aSSUAvNJlNApNLJlVpVJA]]yLlySqN]INLm3UNmN NvN_pm^A\NNvN_m^A]]VT_VpVa_maqlJNmJAiAI]NaSTN_NlApV_T^A[alwV]LœlNm Santa Ana wV_LmJa_pV_qNpamNlvNAmA^A[alAJJN]NlA_pJa_plVIqpV_Tpa lAiVLœlN milNALA_LmNvNlNœlNINUAvVal:UN_Ja^IV_NLwVpUqlIA_N_JlaA JU^N_pV_paœlN- ila_NAlNAmpUNmNJa_LVpVa_mN]NvApNIapUpUNSlNkqN_JyA_LLN mplqJpVvN_NmmaS wV]LœlNm
Projections from the 2024 THIRA and the LA County Climate Vulnerability Assessment Ja_œl^pUApwV]LœlNilaIAIV]VpywV]]Ja_pV_qNpalVmNq_]NmmmV T_VœJA_pSqN]lNLqJpVa_ ]A_LqmNi]A__V_TA_LJ]V^ApNALAipApVa_mplApNTVNmAlNV^i]N^ N_pNLAJlammA]] jurisdictions.
The 2024 THIRA estimates that:
x Over 1.2 million residents live in high-risk wildfire zones. x Communities near the Wildland-Urban Interface (WUI) are at the greatest lVm\NmiNJVA]]ypUamNwVpU]V^VpNLNvAJqApVa_laqpNmA_LpUNJJNmmA_L Functional Needs community.
x 9q]_NlAI]Niaiq]ApVa_mV_J]qLV_TmN_Valm]aw-V_Ja^NUaqmNUa]LmA_L iNai]NwVpULVmAIV]VpVNmSAJNUNVTUpN_NLJUA]]N_TNmLqlV_TNvAJqApVa_m.
6.2.6 Vulnerability
!am_TN]Nmaq_pySAJNmUVTUwV]LœlNvq]_NlAIV]VpyLqNpaVpm NxpN_mVvN:V]L]A_L - 4lIA__pNlSAJN:4 wVpUavNl^V]]Va_lNmVLN_pmpUAp]VvNV_9NlyHigh Fire Hazard Severity Zones (FHSZs). These communities are particularly susceptible because many Ua^Nm ]AJ\ LNSN_mVI]N miAJN œlN-lNmVmpA_p Ja_mplqJpVa_ al ALNkqApN N^NlTN_Jy access.
9q]_NlAI]N iaiq]ApVa_m V_J]qLV_T Iqp _ap ]V^VpNL pa mN_Valm V_LVvVLqA]m wVpU LVmAIV]VpVNm ]aw-V _ J a ^ N U a q m N U a ] L m A _ L p U a m N L N i N _ L N _ p a _ N ] N J p l V J A ] ^ N L V J A ] NkqVi^N_p SAJN mVT_VœJA_p NvAJqApVa_ A_L UNA]pU lVm\m LqlV_T wV]LœlN NvN_pm especially in WUI communities with limited ingress/egress and high fuel loads.
County of Los Angeles
All-Hazards Mitigation Plan
Contextual Overview
Very High FHSZ in LRA jurisdiction includes dense hillside residential areas under local œlNAqpUalVpylNmia_mVIV]Vpy3UNmNAlNma^NaSpUN^ampvq]_Nl AI]NJa^^q_VpVNmLqN papNllAV_vNTNpApVa_A_LJa_mplAV_NLN^NlTN_JyAJJNmm lVpVJA]V_SlAmplqJpqlNVmA]maAplVm\wVpUwV]LœlNNxiamqlNpUlNApN_V_TœlNmpApVa_m]Aw N_SalJN^N_p SAJV]VpVNm UamiVpA]m qpV]VpVNm plA_mialpApVa_ JallVLalm A_L N^NlTN_Jy Ja^^q_VJApVa_mympN^mVmlqipVa_papUNmNNmmN_pVA]mNlvVJNmL qlV_TwV]Lœre events can compound vulnerabilities and delay response and recovery. For a better understanding of critical infrastructure at risk please see Appendix C.
Total Facilities Affected:
x 9NlyVTU!0: 120
x VTU10: 8
x 9NlyVTU10: 76
:VpUpUNJa_pV_qNLNxiA_mVa_aSLNvN]ai^N_pmV_paœlN -ila_NAlNAmUAmmVT_VœJA_p]y V_JlNAmNLwV]LœlNlVm\"A_yUa^NmV_pUN:4]AJ\ilaiNlLNSN_mVI]NmiAJNA_LœlN- lNmVmpA_pIqV]LV_T^ApNlVA]m^A\V_TpUN^iAlpVJq]Al]yvq]_NlAI]NLLVpVa_A]]y]V^Vped evacuation routes in some WUI communities create challenges for emergency lNmia_mNA_LNvAJqApVa_m1plVJpNl|a_V_T]AwmIqV]LV_TlNTq]A pVa_mA_LvNTNpApVa_ management policies are the best practices to reduce risk. 14-091%0!1303
0 %:#
Supervisorial District Population in High-0Vm\
Wildfire Zones
Percentage of District
Population
District 1 150,000 12%
District 2 75,000 6%
District 3 425,000 30%
District 4 250,000 20%
District 5 500,000 32%
County of Los Angeles
All-Hazards Mitigation Plan
Department/
Agency
9NlyVTU1?
!0
VTU1?10 9NlyVTU1?
10
Animal Care and
Control 1 0 1
Fire Department 39 1 14
Health Services 1 0 0
Library 7 1 2
LACMA / NHM 1 0 0
%SœJNaS
Education 3 0 3
Other County
%SœJNm 0 0 0
-Al\mË
0NJlNApVa_ 13 1 12
Public Health 52 4 41
Public :al\m 0 0 0
Sheriff’s
Department 3 1 3
:V]LœlNmpUlNApN_NmmN_pVA]V_SlAmplqJpqlNV_J]qLV_T
x Transportation: Damage to roads and bridges affects evacuation and emergency response.
x Utilities-awNl]V_NmTAmiViN]V_NmA_LwApNlV_SlAmplqJpqlNV_J]qLV_T LA^mAlNvq]_NlAI]NpaSVlNLA^ATN
x Emergency Services: Public safety and healthcare facilities near wildfire- prone areas face operational disruptions.
x Public Services-Al\m]VIlAlVNmmJUaa]mA_LapUNliqI]VJAlNAmJaq]LIN lost or damaged.
County of Los Angeles
All-Hazards Mitigation Plan
#NwN^NlTV_TiAppNl_mmqTTNmppUApJ]V^ApNJUA_TN^AyINV_ŔqN_JV_TwV]LœlNlVm\m in Los Angeles County through:
x Extending fire seasons: VmpalVJA]]yiNA\SVlNmNAma_aJJqllNLSla^ q_N pa#avN^INlIqpSVlNmAlN_awmpAlpV_TA_Lburning year-round. x Increasing fuel dryness: Higher temperatures and prolonged droughts lNLqJNvNTNpApVa_^aVmpqlN]NvN]m^A\V_TSVlNm^alNV_pN_mN x 0AVmV_TSVlNSlNkqN_JyappNlLlVNlJa_LVpVa_mJa_plVIqpNpa^alN SlNkqN_pVT_VpVa_miAlpVJq]Al]yV_:4AlNAm.
Extent of Exposure
x Total Area Exposed: 243.72 sq mi
x Supervisorial Districts (SD) Impacted:
o SD3: 117.95 sq mi (27.29%)
o SD5: 95.61 sq mi (3.36%)
o SD1: 16.23 sq mi (4.60%)
o SD4: 9.10 sq mi (4.27%)
o SD2: 4.83 sq mi (1.33%)
alAINppNlvVmqA]lNilNmN_pApVa_aSpUVm:V]LœlNA|AlLwVpUV_pUN!aq_pyi]A__V_T AlNAi]NAmNlNSNlN_JNiiN_LVx for several Fire Hazard Severity Zone maps.
6.2.7 Impacts
^iAJpmSaliAmpœlNmvAlyLNiN_LV_Ta_ scope and severity V_J]qLV_TpUN A_qAly
œlNmV_J]qLV_TpUN-A]VmALNmA_LApa_VlNmlNmq]pNLV_wVLNmilNALLNmplqJpVa_ AJlamm!am_TN]Nmaq_pyIql_V_TavNlAJlNmA_LLNmpla yV_T^alNpUA_ mplqJpqlNmJa^IV_NLwVpU_NAl]yJVvV]VA_SApA]VpVNm 3UNmNNvN_pmJAqmNL cascading impacts mqJU Am ila]a_TNL iawNl aqpATNm LNTlALNL wApNl ilNmmqlN ASSNJpV_TœlNœTUpV_TA_LlNmVLN_pVA]mqii]yA_LavNlwUN]^NLN^ NlTN_JymNlvVJNm Transportation routes and communications infrastructure were disrupted. a^^q_VpVNmNmiNJVA]]yV_pUN:V]L]A_L -Urba__pNlSAJN:4 NxiNlVN_JNL^A[al NJa_a^VJ]ammNmLqNpapUNLNmplqJpVa_aSUa^NmIqmV_NmmNmA_ LiqI]VJSAJV]VpVNm Post-œlN UA|AlLm ]V\N LNIlVm Ŕawm A_L ]A_Lm]VLNm SqlpUNl Ja^iaq_LNLlNJavNly JUA]]N_TNm wVpU wApNl V_SlAmplqJpqlN Ja_pA^V_ApVa_ A_Lsedimentation requiring N^NlTN_Jy lN^NLVApVa_ 3UN mJaiN A_L mNvNlVpy aS pUNmN œlNm q_LNlmJalN pUN increasing vulnerability of critical infrastructure and the urgent need for enhanced mitigation strategies across high-risk zones.
County of Los Angeles
All-Hazards Mitigation Plan
Problem Statement
Many hillside communities within LRA Very High FHSZ zones face critical access and wApNlmqii]yVmmqNmLqlV_TœlNm3UNmNAlNAmaSpN_V_J]qLNATV_TmplqJpqlNmA_L_Allaw laALmJa^i]VJApV_TœlNœTUpV_TA_LNvAJqApVa__vNmp^N_pmV_LNSN_mVI]NmiAJN]aJal JaLNN_SalJN^N_pA_LJa^^q_VpywV]LœlNilapNJpVa_i]A__V_TAlNvVpA]pamAvV_T]VvNm and minimizing losses.
6.2.8 Mitigation and Preparedness
Los Angeles County is implementing a multi-ATN_JyAiilaAJUpa^VpVTApNwV]LœlNlVm\m Key strategies include:
x Community Wildfire Protection Plans (CWPPs): Strengthening fire prevention measures in high-risk areas.
x Community Preparedness: Educating residents on wildfire readiness pUlaqTUaqplNAJUJA^iAVT_mN^NlTN_JyA]NlpmympN^mA_L_NVTUIalUaaL preparedness programs.
x NSN_mVI]N1iAJN0NkqVlN^N_pmEnforcing brush clearance around structures.
x Enhanced Building Codes: Promoting fire-resistant materials for new developments.
x 9NTNpApVa_"A_ATN^N_pReducing fuel loads through prescribed burns and hazardous tree removal.
x Evacuation Planning: ^ilavV_TJaalLV_ApVa_INpwNN_%"!1 !aA_LapUNl[qlVmLVJpVa_mpaN_mqlNJ]NAlNvAJqApVa_ia]VJVNmA_L procedures.
LLVpVa_A]LNpAV]ma_pUNaq_py¯milaAJpVvNA_La_TaV_TNSSalpmpalNLqJNwV]LœlNlVm\ including long- pNl^ i]A__V_T V_SlAmplqJpqlN UAlLN_V_T A_L Ja^^q_Vpy-based V_VpVApVvNmVm]aJApNLV_pUNLNLVJApNLmNJpVa_pVp]NL¬"VpVTApVa_1plApNTVNm
6.2.9 Summary
:V]LœlNmlN^AV_a_NaSpUN^ampmVT_VœJA_pUA|AlLmV_!am_TN]Nmaq_pyiamV_TlVm\m pa]VSNilaiNlpyA_LJlVpVJA]V_SlAmplqJpqlN3UNNxiA_mVa_a SLNvN]ai^N_pV_pa:4 AlNAmV_JlNAmV_TœlNmNvNlVpyLqNpaJ]V^ApNJUA_TNA_La_TaV _TJUA]]N_TNmwVp h NvAJqApVa_A_L^VpVTApVa_lNkqVlNilaAJpVvNJaalLV_ApNLNSSalp mAJlammATN_JVNm 1plN_TpUN_V_TœlNilNvN_pVa_ia]VJVNmV^ilavV_TN^NlTN_JylNmia_mNJaalLV_ApVa_ A_L V_pNTlApV_T J]V^ApN ALAipApVa_ ^NAmqlNm AlN NmmN_pVA] pa N_UA_JV_T wV]LœlN resilience for Los Angeles County.
County of Los Angeles
All-Hazards Mitigation Plan
6.3 Earthquake
6.3.1 Nature
Earthquakes occur due to the sudden release
a S N _ N l T y V _ p U N A l p U µ m J l q m p T N _ N l A p V _ T seismic waves that cause ground shaking.
3UNmNNvN_pmaSpN_plVTTNlNLIy^avN^N_p
A]a_TSAq]p]V_NmvAlyV_V_pN_mVpyLNiN_LV_T
a_SAJpalmmqJUAm^AT_VpqLN LNipU A_L
proximity to populated areas. In addition to
pUNV_VpVA]mUA\V_TmNJa_LAlyUA|AlLmmqJUAm
mqlSAJN SAq]pV_T ]VkqNSAJpVa_ ]A_Lm]VLNm
tsunamis A_L ASpNlmUaJ\m JA_ walmN_ pUN
LA^ATN!am_TN]Nmaq_py]aJApNLV_A
UVTU]yAJpVvNmNVm^VJlNTVa_SAJNmmVT_VœJA_p
risks from thNmN_ApqlA]NvN_pm_NJNmmVpApV_T
extensive mitigation efforts and
preparedness planning.
x The most common effects of
NAlpUkqA\NmV_J]qLNvVa]N_pmUA\V_T
mplqJpqlA]LA^ATNA_LLVmlqipVa_mpaV_SlAmplqJpqlN
x 1NJa_LAlyNSSNJpmJA_V_J]qLNIqpAlN_ap]V^VpNLpaqpV]VpVN maqpATNmplASSVJ Ja_TNmpVa_A_LplA_mialpApVa_mympN^mINV_TV^iAmmAI]NA_LA_V_JlNAmNaSSVlN lVm\mSla^Ila\N_TAmA_LwApNl]V_Nm
CouCCCCouCouCouCouCouCououououCouCoCooouC untnntntyntytytyntynnnnnnnnn ofoffoffof LoLoLos As As As As A AAAAs AsAs As As Angengengengeeeengengegengengengengengegengegengeeeegeengengeengengeggengngennng lesleslesesleslesesleslesleslesleslesslesesleslesslesesseslesesesl sseseeesees AllAllAAllAllAllAllAllAllAlllAllAlAlAlllAllAAAllAllAlAlAAl ------------
HazazHazHazHazHazHazazzHazHazHazazHazHazazHaHaHazHazHazazazHazazHazHazazzzzzHa ardardardardardardardardardardardardrdardardardardrdardarddarddardaaardaardaarddardarddrdrdardardrdaa MsMsMsMsMsMsMsMsMsMMsMMsMsMMsMsMsMsMsMsMsMMsMs MMMs MMs Ms MsMsMs Mss Msss Ms itiitiiiitiititiiiitiiititiitiitititiitttttitittiititittitiiitiitiggatgatttgatattgattgatgatggagatgatgatgatttgggatgagatttgattataggag iiiionionnioniononiononionioniononniiononnnioonnnooonioonniioionnio aPlaPlalaPlaPlaaPlaPlaaPllPlPlaPlalPPlaPlaPlaPllPlPlPlPlPlPlPlaPlaPlaaPPlaPlaPlP aaPlaPllaPl nnnnnnnnnnnnnnnnn
County of Los Angeles
All-Hazards Mitigation Plan
x AlpUkqA\NmaJJqlwVpU]Vpp]Npa_awAl_V_T^A\V_TilNiAlNL_Nm mNmmN_pVA]Sal minimizing loss of life and property.
6.3.2 Location
!am_TN]Nmaq_pyVma_NaSpUN^ampmNVm^VJA]]yAJpVvNlNTVa_ mV_pUN4_VpNL1pApNm with multiple active fault systems capable of generating destructive earthquakes.
Major faults include:
x San Andreas Fault – Capable of M 8.0+
x Newport-Inglewood Fault – M 7.4
x Malibu Coast Fault System – M 6.7
x San Fernando Fault – M 6.6
x Santa Monica Fault – M 7.0
x Whittier Fault – M 7.2
x Sierra Madre Fault – M 6.0-7.0
For a better visual representation of this Earthquake Hazard within LA County planning AlNAi]NAmNlNSNlN_JNiiN_LVxfor earthquake fault maps.
6.3.3 Extent
JJalLV_Tpa41Na]aTVJA]1qlvNypUNlNAlNpwapyiNmaSNAlpUkqA\N^NAmqlN^N_pm magnitude (Mw) and intensity (i). Magnitude is a measure of the energy released at the source of the earthquake. Intensity scale help measure impact on people and structures.
AlpUkqA\NV^iAJpVmIAmNLa_^AT_VpqLNmJA]NVmAmSa]]awm:
x Great—"wÁ
x Major—Mw = 7.0 – 7.9
x Strong—Mw = 6.0 – 6.9
x Moderate—Mw = 5.0 – 5.9
x Light—Mw = 4.0 – 4.9
x Minor—Mw = 3.0 – 3.9
x Micro—Mw < 3
County of Los Angeles
All-Hazards Mitigation Plan
"aLVœNL"Nlcalli Intensity 1JA]NVmSla^pa;wUVJUlNSNlmAm_apSN]pA_L;Am extreme.
Figure 6.3.1"aLVœNL"Nlcalli Intensity Scale
Over 75% of unincorporated Los Angeles County is at risk for severe to extreme shaking in a future earthquake.
3UNlNTVa_µmLN_mNqlIA_N_vVla_^N_pJa^IV_NLwVpUATV_TV_SlAmplqJpqlNV_JlNAmNm the likelihood of extensive damage and prolonged recovery times.
Faults running beneath critical V_SlAmplqJpqlNJallVLalmV_J]qLV_TSlNNwAymA_LiawNl TlVLmiamNAmVT_VœJA_ppUlNAppaiqI]VJmASNpyA_LNJa_a^VJmpAIV]Vpy of the planning area.
County of Los Angeles
All-Hazards Mitigation Plan
6.3.4 History
!am_TN]Nmaq_pyUAmA]a_TUVmpalyaSLNmplqJpVvNNAlpUkqA\N mwVpUma^NaSpUN earliest recorded events dating back to the early 19th century. The San Juan Capistrano AlpUkqA\NaS"
wAmA^a_TpUNœlmppaINLaJq^N_pNL JAqmV_TpUN
collapse aS"VmmVa_1A_ qA_AiVmplA_aA_LlNmq]pV_TV_SApA]VpVNm %vNlpUNyNAlm pUNJaq_pyUAmNxiNlVN_JNL_q^NlaqmmVT_VœJA_pkqA\NmV_J]qLV_ TpUNLNvAmpApV_T
alp3N[a_AlpUkqA\N" pUN1A_Nl_A_LaAlpU kqA\N" A_L the infamous #alpUlVLTNAlpUkqA\N" wUVJUJAqmNLIV]]Va_mV_LA ^ATNm and led to widespread infrastructure failures. There have been no federal declarations or state proclamations for earthquakes V_pUN]AmpœvNyNAlm "A[alAlpUkqA\NmV_!am_TN]Nmaq_py– Present) Date Magnitude Name / Location Notable Impact
NJN^INl
1812 7.5
San Juan
Capistrano
Earthquake
Destroyed Mission San Juan
AiVmplA_a\V]]NLiNai]N
NJN^INl
1812 7.1 West Ventura
Earthquake
AqmNLmVT_VœJA_pmUA\V_TV_
Southern California.
A_qAly
7.9 Fort Tejon
Earthquake
Largest earthquake on the San
_LlNAmAq]plqipqlNL
miles.
q]y
7.5 Kern County
Earthquake
Strong shaking felt in Los
_TN]Nm^A[alLA^ATNpa
A\NlmœN]L
NIlqAly 6.6 San Fernando
Earthquake
LNApUm¸
^V]]Va_V_
LA^ATNmJa]]AimNaS9NpNlA_m
Hospital.
%JpaINl 5.9 Whittier Narrows
Earthquake
LNApUmV_[qlVNm¸
million in damages.
NIlqAly
1990 5.7 Upland Earthquake V_[qlVNm¸^V]]Va_V_ damages.
County of Los Angeles
All-Hazards Mitigation Plan
6.3.5 Probability
Trends in Seismic Activity
Over 163 earthquakes of M 5.0 or greater have been recorded in Southern California since 1812.
3UN1A__LlNAmAq]plN^AV_mpUNTlNApNmpmNVm^VJUA|AlLwVpUA ÈJUA_JNaSA_"
6.7+ event in the next 30 years.
qpqlNAlpUkqA\N%JJqllN_JN
The U.S. Geological Survey (USGS) estimates the following probabilities for a major earthquake in Los Angeles County in the next 30 years:
x 60% chance of an M 6.7+ earthquake
x 46% chance of an M 7.0+ earthquake
x 31% chance of an M 7.5+ earthquake
6.3.6 Vulnerability
3UN Jaq_py¯m vq]_NlAIV]Vpy pa NAlpUkqA\Nm NxpN_Lm INya_L iUymVJA] V_SlAmplqJpqlN ASSNJpV_TVpmlNmVLN_pmA_LNmmN_pVA]mNlvVJNm%]LNlIqV]LV_TmiAlpVJq]Al]yq_lNV_SalJNL masonry and soft- mpalymplqJpqlNmAlNApUVTUlVm\aSJa]]AimNiamV_TmVT_VœJA _p q_N 5.6 Sierra Madre
Earthquake
LNApU½V_[qlVNm¸
million in damages.
A_qAly 6.7 Northridge
Earthquake
LNApUmV_[qlVNm¸
IV]]Va_V_LA^ATNmSlNNwAym
collapsed.
q]y 5.5 Chino Hills
Earthquake
V_[qlVNm^V_almplqJpqlA]
damage.
"AlJU 5.1 La Habra
Earthquake
NwV_[qlVNm¸^V]]Va_V_
damages.
q]y 7.1 Ridgecrest
Earthquake
Widespread damage in
1aqpUNl_A]VSal_VA
infrastructure impacts.
County of Los Angeles
All-Hazards Mitigation Plan
dangers to residents and businesses. 1NVm^VJlNplaœppV_TNAl]ywAl_V_TmympN^mA_L mplVJpNlIqV]LV_TJaLNmUAvNV^ilavNLlNmV]VN_JNIqp vulnerabilities remain in older structures and critical infrastructure.
lVpVJA]_SlAmplqJpqlNAp0Vm\
x Highways, bridges, and transportation routes: A major earthquake could mNvNlN]yLVmlqip^aIV]Vpy shipment of goods and services while also delaying emergency response and evacuations. "A[alUVTUwAymmqJUAmIqp_ap]V^VpNL to the I-
-41----
-A_L-105 could be impacted.
x Energy grids and water system: Disruptions could leave millions without power and clean water.
x Hospitals and emergency services:
UamiVpA]mA_LœlNmpApVa_mV_pUN
Los Angeles County could suffer functional impairments. x Unreinforced masonry and soft-story buildings: Many older structures are highly susceptible to collapse during strong ground shaking. aq_py1iNJVœJlVpVJA]AJV]VpVNmSSNJpNL
x Fire Department: 314 facilities (93.18%)
x Public Works: 201 facilities (87.39%)
x Health Services: 56 facilities (85.71%)
x Public Health: 37 facilities (92.50%)
x Libraries: 78 branches (89.66%)
x Parks: 179 (97.79%)
x Education: 70 (85.37%)
!am_TN]Nmaq_py]VNmAppUNV_pNlmNJpVa_aS^q]pVi]N^A[alS Aq]p]V_NmV_J]qLV_TpUN 1A__LlNAmAq]pJJalLV_TpapUNUA|AlL^AplVxpUNlVm\aSvVa]N_pTlaq_LmUA\V_TVm ilNvA]N_p Jaq_pywVLN iAlpVJq]Al]y V_ qlIA_ JN_pNlm A_L lNTVa_m wVpU JlVpVJA] infrastructure. The potential consequences of violent seismic shaking include wVLNmilNALmplqJpqlA]LA^ATNLVmlqipVa_aSmNlvVJNmNJa_a^VJ ]ammNmA_LUq^A_ casualties.
-aiq]ApVa_mAp0Vm\
x The THIRA estimates over 2 ^V]]Va_lNmVLN_pmJaq]LINmVT_VœJA_p]yV^iAJpNLV_ A^A[almNVm^VJNvN_piAlpVJq]Al]ypUamNV_UVTU-risk seismic zones.
County of Los Angeles
All-Hazards Mitigation Plan
x People Experiencing Homelessness (PEH) populations: ½ unhoused
individuals in Los Angeles County live in areas at risk of violent shaking. x Low-income and individuals with access and functional needs (AFN): For more details on impacted population please see Section 5.
Extent of Exposure
x Total Area Exposedmk^V
x Supervisorial Districts (SD) Impacted:
o SD5
mk^V
È
o SD3: 379.41 sq mi (87.99%)
o SD1: 349.17 sq mi (98.95%)
o SD2: 362.95 sq mi (99.99%)
o SD4: 210.92 sq mi (99.10%)
6.3.7 Impacts
Los Angeles County has a long history of experiencing damaging earthquakes due to Vpm]aJApVa_A]a_T^q]pVi]NAJpVvNSAq]pmympN^mV_J]qLV_TpUN 1A__LlNAm#Nwialp - _T]NwaaLA_L:UVppVNlSAq]pmVmpalVJNAlpUkqA\NmmqJUAmpU N1A_Nl_A_La (M6.6) and 1994 Northridge (M6.7) events caused catastrophic losses. The San Nl_A_LaNAlpUkqA\NlNmq]pNLV_
LNApUmpUNJa]]AimNaSUami VpA]mplqJpqlNmA_L
avNl¸
^V]]Va_V_LA^ATNmwUV]NpUN#alpUlVLTNNAlpUkqA\NJ AqmNL LNApUm
^alNpUA_V_[qlVNmA_LA_NmpV^ApNL¸IV]]Va_V_NJa_a ^VJ]ammNmV_J]qLV_T widespread infrastructure failures such as collapsed freeways and damaged utility systems.
Impacts from future major seismic events are projected to be even more severe due to iaiq]ApVa_LN_mVpyATV_TV_SlAmplqJpqlNA_LV_JlNAmV_TLNvN]a i^N_pV_mNVm^VJA]]y vulnerable areas. Over 75% of unincorporated Los Angeles County is at risk of severe to extreme ground shaking. Current estimates suggest that a large-magnitude NAlpUkqA\NJaq]LLVmi]AJNqipa^V]]Va_iNai]NV_[qlNal\V]]pUaqmA_LmA_LlNmq]p V_avNl¸IV]]Va_V_Ja^IV_NLNJa_a^VJ]ammNmV_J]qLV_T¸ IV]]Va_V_ilaiNlpy LA^ATNA_L¸IV]]Va_V_IqmV_NmmV_pNllqipVa_m
County of Los Angeles
All-Hazards Mitigation Plan
3UN aq_py¯m JlVpVJA] mympN^m iawNl wApNl plA_mialpApVa_ UNA]pUJAlN A_L Ja^^q_VJApVa_mAlNNmiNJVA]]yvq]_NlAI]N^A[alNAlpUkqA\NJaq]LV^iAVlqipa
UamiVpA]m A_L œlN mpApVa_m A_L LVmlqip JlVpVJA] V_SlAmplqJpqlN Sal ^V]]Va_m PopulationmwVpUUNVTUpN_NLvq]_NlAIV]VpyV_J]qLNpUN ½iNai]NNxiN lVN_JV_T
Ua^N]Nmm_Nmm pUamN wVpU AJJNmm A_L Sq_JpVa_A] _NNLm A_L lNmVLN_pm aS a]LNl unreinforced masonry and soft-story structures.
:VpUaqpmqSœJVN_p^VpVTApVa_ASqpqlNNAlpUkqA\NJaq]LlNmq]p V_JAmJALV_TSAV]qlNm across multiple sectors and prolong the County’s recovery for years. These risks UVTU]VTUp pUN qlTN_Jy Sal Ja_pV_qNL V_vNmp^N_p V_ mNVm^VJ lNplaœppV_T mplVJpNl enforcemN_paSIqV]LV_TJaLNm NxiA_LV_TmpApNwVLNNAl]ywAl_V_TmympN^ mA_L equitable preparedness programs targeting at-risk vulnerable populations. x Casualties and injuries: NiN_LV_Ta_pUNpV^NaSLAyA_L]aJApVa_pUaqmA_Lm could be injured or killed in a severe earthquake.
x Economic disruption: mVT_VœJA_pNAlpUkqA\NJaq]LUA]pIqmV_NmmaiNlApVa_m LA^ATNmqii]yJUAV_mA_LSalJNpUaqmA_LmV_paq_N^i]ay^N_p x Housing displacement: _NmpV^ApNL^V]]Va_lNmVLN_pmJaq]LINLVmi]AJNL with tens of thousands requiring emergency sheltering.
Economic Impact
A major earthquake in Los Angeles County Jaq]LlNmq]pV_avNl¸IV]]Va_V_NJa_a^VJ ]ammNm wVpUApapA]aS¸plV]]Va_-dollar exposure. Losses can include:
x ¸IV]]Va_V_IqmV_NmmV_pNllqipVa_m
x ¸
IV]]Va_V_]ampNJa_a^VJAJpVvVpy
x ¸IV]]Va_V_ilaiNlpyLA^ATNm
Problem Statement
The pervasive exposure of Los Angeles County to violent earthquake shaking presents AmympN^VJpUlNAppaiqI]VJmASNpyNJa_a^VJmpAIV]VpyA_LNmmN_pVA]mNlvVJNm#NAl]yA]] major departments and infrastructure elements are located within high-shaking hazard |a_Nm3UNNxpN_mVvNlNAJUAJlammA]]œvN1qiNlvVmalVA]VmplVJ pm1 A^i]VœNmpUN JUA]]N_TN UVTU]VTUpV_T pUN qlTN_p _NNL Sal lNplaœppV_T iqI]VJ N L q J A p V a _ ilNiAlNL_NmmilaTlA^mA_LlNmV]VN_pLNmVT_ia]VJVNmAV]qlNp aALLlNmmpUVmUA|AlL could lead to catastrophic loss of life and functionality in the event of a major seismic event.
County of Los Angeles
All-Hazards Mitigation Plan
6.3.8 Mitigation and Preparedness
Efforts to reduce earthquake risks in Los Angeles County include strengthening IqV]LV_T JaLNm N_UA_JV_T N^NlTN_Jy ilNiAlNL_Nmm A_L lNplaœppV_T vq]_NlAI]N structures.
NyNSSalpmpa^VpVTApNNAlpUkqA\NlVm\mV_J]qLN
x 1plN_TpUN_V_TIqV]LV_TJaLNmA_LN_SalJV_TlNplaœppV_T]Awm x Upgrading critical infrastructure
x Expanding public education and early warning systems
x Enhancing emergency response planning
yilaAJpVvN]yV^i]N^N_pV_TpUNmN^NAmqlNm!am_TN]Nmaq_py AV^mpalNLqJN JAmqA]pVNmV_SlAmplqJpqlNLA^ATNA_LNJa_a^VJ]ammNmV_SqpqlNmNVm^VJNvN_pm 1NVm^VJ0NplaœppV_T-laTlA^m
x 1aSpmpalylNplaœpilaTlA^ : Mandates seismic upgrades for older apartment buildings.
x Non-LqJpV]NJa_JlNpNIqV]LV_TlNplaœpm : Strengthens older commercial and residential structures.
x amiVpA]mA_LN^NlTN_JySAJV]VpVNmlNplaœppV_T : Ensures critical services remain operational post-earthquake.
-a]VJyA_L0NTq]Apaly"NAmqlNm
x Assembly Bill (AB) 1857: Strengthens building standards for multi-story structures.
x AB 2681: Requires cities and counties to inventory vulnerable buildings. x Updated California Building Code (CBC): Enforces stricter seismic design criteria for new construction.
x Public Education: 3 N A J U V _ T p a l a i a v N l A _ L a ] L % _ p U N U a q m N U a ] L ilNiAlNL_NmmJUNJ\]VmpNLqJApNlNmVLN_pma_N^NlTN_JylNmia_mNlNplaœppV_T and disaster preparedness.
x Early Warning/ ShakeAlert System: Provides real-time earthquake early warnings to residents via mobile alerts and public messaging.
x Public earthquake drills: Annual Great California ShakeOut encourages preparedness.
County of Los Angeles
All-Hazards Mitigation Plan
6.3.9 Summary
!am_TN]Nmaq_pylN^AV_mApUVTUlVm\SalLNvAmpApV_TNAlpUkq A\NmwVpUmJVN_pVœJ ila[NJpVa_mV_LVJApV_TAmpla_T]V\N]VUaaLaSAmVT_VœJA_pmNVm ^VJNvN_pV_pUNJa^V_T LNJALNm 3UN lNTVa_ UAm NxiNlVN_JNL _q^Nlaqm UVmpalVJ NAlpUkqA\Nm A_L pUN potential for future large-scale disasters remains ever-present. While advances in N_TV_NNlV_T N^NlTN_Jy ilNiAlNL_Nmm A_L ^VpVTApVa_ NSSalpm UAvN V^ilavNL lNmV]VN_JN JUA]]N_TNm iNlmVmp iAlpVJq]Al]y lNTAlLV_T ATV_T V_SlAmplqJpqlN A_L vulnerable communities. ConpV_qNLV_vNmp^N_pmV_lNplaœppV_TiqI]VJNLqJApVa_A_L NAl]ywAl_V_TmympN^mwV]]INJlVpVJA]V_^V_V^V|V_TJAmqA]pVNm NJa_a^VJ]ammNmA_L recovery challenges in future earthquakes.
County of Los Angeles
All-Hazards Mitigation Plan
CouCouCouCouCCouCouCouCououCoCouCouCouCououCououCouCouCouCouCouCouCouCououCouuCCooCouCouCouCououCoCoCouCoCoCouCCCouCCoouuCCoooCoCoCCounnntntyntynntyntyntntyntyntytyntyntyntyntytyntyntyntyntyynnntyntyntynntytyntyntyntytnntynntntyntyntntyyntntnntyyntntytyyntyntyynntynnnnntynn ynnttyttyyyyyyyy ofofofofofofoffofofofofoffofofofoofoofofofofofoofofofoffofofofofofofffofofofoffofofoooofooooofofofofoffofffofofooooof LoLoLoLLoLoLoLoLoLoLoLoLLoLoLLooLoLoLoLLoLoLoLLoLLoLLoLoLoLoLoLoLoLooLooLoLLoLoLooLoLooLLLooLooooLoLLLoLoLoLLLLooLooLoooLLLoLLoooLooooLLoLoooLLooLLLooLoLLLLLoLLL s As As Ass s As AAs As As As As As AsAsAsAsAsAsAAs As s As AAAAsAs AAs As As As As A As As As As As AsAAs As As Ass sAs As AAsAsAss AsAs AssAAs AssAsAsAss AssAss AssAAAAAss AAAnnggeengnnnnnnnnnnnnnnnnnnnnn les AlAlAlAlAAAlAllAAlAllAllAlAlAllAllAAlAllAAllAAAAllAllAAAAAllAllAAAAAlAlAllAlAllAllAllAllAllAAAAAlAlAlAlAAAllAllAAAAAlAllAAAAllAAlAAAAAAAAA lAAlAAllAAAllAAA lAllAA lAA lAA llA -------------
HaHaHHHazHHHazHaHaazHazHazHazHazHazHazHazzHazHazHazHazHazHazHazHazHazzzHaHHazazHazHHaHazazHHazHHHH zHazHazzzzzHaHazzHHHHHazHazHHHaaHHaazzzHHazzHHHH zHHaHHazzazHHHHHHHHaazHHaaazzardardardardardardardardardarardaraardardardardardaardardrdardardrdardarddardardaardardardardardardrardarrrarardarrarrddardardrrdardardrrrrrrdddrdrdarddrdrardardaaaaaraaaa daa s Ms Ms MMs Ms Ms Ms Ms sMsMsMsMsMsMsMs MssMs MMsMsMsMsMs MsMsMssMsMsMsMs Ms MMs Ms MMsMsMsMMs MMMMMs MMMMMMMs MMMMMMMMMMMMMMMMMMMMMMs MMMMMMMMMMMs MMMs MMMMMs MMMMMMMMMiitiititiitiitiiitiitittitiittitttitittitittittttitititiiititiiititittitiitttiitttiittitittttittttiiitiit gagatgatgatattgatgagagg ionionon PlaPl n
6.4 Extreme Heat
6.4.1 Nature
Extreme heat refers to prolonged periods of
UVTU pN^iNlApqlNm aSpN_ AJJa^iA_VNL Iy
UVTUUq^VLVpyiamV_TmVT_VœJA_pUNA]pUlVm\m
such as heat exhaustion and heat stroke. The
urban heat island (UHI) NSSNJpilNvA]N_pV_
LN_mN]yIqV]pAlNAm]V\N!am_TN]Nmaq_py
V _ p N _ m V œ N m p U N m N J a _ L V p V a _ m I y A I m a l I V _ T and retaining heat. The changing climate
conditions through time in the region
exacerbate for the rising of daily temperature
and for the increasing of extreme heat days
in the County. This leads paUNA]pUVmmqNm
inJlNAmN N_NlTy LN^A_L A_L mplAV_ a_
infrastructure.
6.4.2 Location
Los Angeles County is particularly susceptible to extreme heat due to its diverse geography and urban density. ]]aS!am_TN]Nmaq_py^AyNxiNlVN_JNNxplN^NUNAp nonetheless i_]A_LlNTVa_mV_J]qLV_TpUNvA]]NymA_LUVTULNmNlpAlNAmNxiN lVN_JN
County of Los Angeles
All-Hazards Mitigation Plan
higher temperatures compared to coastal areas. The urban heat island (UHI) effect can increase temperatures in cities and developed areas than the less developed areas.
Urban centers with extensive concrete and asphalt surfaces further amplify heat lNpN_pVa_Ja_plVIqpV_TpaN]NvApNLpN^iNlApqlNmand increased UHI effect in the county.
6.4.3 Extent
The severity of heat events in Los Angeles County has been increasing. Projections V_LVJApNAmVT_VœJA_plVmNV_pUNSlNkqN_JyA_LV_pN_mVpyaSUNApwAvNmwVpUV_]A_LAlNAm potentially experiencing temperatures exceeding 110°F. The urban heat island effect JA_JAqmNqlIA_AlNAmpaINmNvNlA]LNTlNNmwAl^NlpUA_pUNVll qlA]Jaq_pNliAlpm exacerbating the impact of heat waves. The chart below shows the levels of heat wave impacts qmNL pa ^NAmqlN UNApwAvN mNvNlVpy NAp0Vm\ A_ NxiNlV^N_pA] ^NAmqlN developeLIypUN#:1V_Ja]]AIalApVa_wVpUpUNJ]AmmVœNmUNApNvN_ pmIypUNVl impact on human health. It ranges from Green (0) which is little or no risk to Magenta wUVJU^NA_mNxplN^NUNApwVpU_aavNl_VTUplN]VNS Category Figure 6.4.1 0Vm\aSNAp-0N]ApNL^iAJpm
lNN_
0 Little to no risk from expected heat.
Yellow
1 Minor - This level of heat affects primarily those individuals extremely mN_mVpVvNpaUNApNmiNJVA]]ywUN_aqpLaalmwVpUaqpNSSNJpVvNJaa]V_TA_Lal adequate hydration.
Orange
2 Moderate - This level of heat ASSNJpm^ampV_LVvVLqA]mmN_mVpVvNpaUNAp especially those without effective cooling and/or adequate hydration.
Impacts possible in some health systems and in heat-sensitive industries. 0NL
3 Major - This level of heat affects anyone without effective cooling and/or ALNkqApNUyLlApVa_^iAJpm]V\N]yV_ma^NUNA]pUmympN^mUNAp -sensitive industries and infrastructure.
Magenta
4 Extreme - This level of rare and/or long-duration extreme heat with little to no overnight relief affects anyone without effective cooling and/or adequate UyLlApVa_^iAJpm]V\N]yV_^ampUNA]pUmympN^mUNAp-sensitive industries and infrastructure.
EĂƟŽŶĂůtĞĂƚŚĞƌ^ĞƌǀŝĐĞ ;Et^Ϳ, 2024
County of Los Angeles
All-Hazards Mitigation Plan
qTqmpINV_TpUNUappNmp^a_pUaSpUNyNAlpUAppUNi]A__V_TAlNANxiNlVN_JNmpUN Figure 6.4.2IN]awmUawmpUNAvNlATNUVTUpN^iNlApqlNSalqTqmpV_!am _TN]Nmaq_pymmUaw_pUNpN^iNlApqlNvAlVNmIy]aJApVa_IqplN^AV_mUVTUNl than average monthly temperature.
Figure 6.4.2͕DĞĂŶDĂdždĞŵƉĞƌĂƚƵƌĞĨŽƌƵŐƵƐƚϮϬϮϰ͕EĂƟŽŶĂůtĞĂƚŚĞƌ^ĞƌǀŝĐĞ
6.4.4 History
NJAqmN aS pUN JUA_TV_T J]V^ApN Ja_LVpVa_m A_L pUN TNaTlAiUVJA]] a J A p V a _ ! a m Angeles County has been experiencing extreme heat waves in the past years. It has a UVmpalyaSNxplN^NUNApNvN_pmwVpUpN^iNlApqlNmSlNkqN_p]ylNAJUV_TLNTlNNmal ^alNNmiNJVA]]yLqlV_TpUNmq^^Nl^a_pUm_ma^NJAmNmpUNmNNxplN^NUNApNvN_pm are record-breaking heat waves surpassing their all-time highs.
Extreme Heat events include:
x August 2020: mNvNlNUNApwAvN]NLpawVLNmilNALiawNlaqpATNmASSNJpV_T _NAl]y
lNmVLN_pm
County of Los Angeles
All-Hazards Mitigation Plan
x September 2020: The San Fernando Valley recorded a record high temperature of 121°F.
x August 2022: A record-breaking heatwave in late summer exceeded 100°F x September 2024: A severe September heatwave pushed temperatures 10- ÑAIavN_al^A]UVppV_TÑV_!a_T
NAJU
The History of Extreme heat events highlight the increasing trend of extreme heat occurrences in the region. There have been no federal declarations or state ilaJ]A^ApVa_mSalNxplN^NUNApV_pUN]AmpœvNyNAlm Even though there were no LNJ]AlNLNxplN^NUNApN^NlTN_JVNmpUNJaq_pyUAmVmmqNLmNvNlA ]UNApA]NlpmA_L taken measures to protect residents from the impacts of heat waves during these periods.
6.4.5 Probability
xplN^NUNApNvN_pmAlNA_A__qA]aJJqllN_JNV_!am_TN]Nmaq_pypUaqTUmNvNlVpy aSmqJUNvN_pmvAlyiNlyNAlIAmNLa_apUNlJa_LVpVa_mmqJUAm]#Vño. Climate models project a substantial increase in the likelihood of extreme heat events in Los Angeles County. By mid-JN_pqlypUNJaq_pyJaq]LNxiNlVN_JN^alNpUA_œvN^A[alUNApwAvNm A__qA]]ywVpUma^N^aLN]mmqTTNmpV_TqipapN_Sa]LV_JlNAmNmV _SlNkqN_Jy3UVm heightened probability necessitates proactive mitigation and adaptation strategies.
Figure 6.4.3, ǀĞƌĂŐĞdĞŵƉĞƌĂƚƵƌĞϭϵϬϬ-2025, NOAA, NCEI, 2025.
6.4.6 Vulnerability
xplN^NUNApiamNmAmVT_VœJA_pA_LTlawV_TpUlNAppa!am_TN] Nmaq_pywUNlN lVmV_TpN^iNlApqlNmqlIA_UNApVm]A_LmA_LwVLNmilNALmaJVA]vq]_NlAIV]VpyV_pNlmNJp 3UamN^ampAplVm\V_J]qLNpUNN]LNl]y]aw-V_Ja^NUaqmNUa]Lm]AJ\V_TAVlJa_LVpVa_V_T County of Los Angeles
All-Hazards Mitigation Plan
iNai]NNxiNlVN_JV_TUa^N]Nmm_Nmm- V_LVvVLqA]mwVpUAJJNmmA_LSq_JpVa_A]_NNLm # A_LpUNaq_py¯m]AlTNiaiq]ApVa_aSaqpLaalA_L_a_ -air-conditioned indoor workers. Infrastructure is also strained N]NJplVJVpyLN^A_LmiV\NmLqlV_TUNApwAvNm often overwhelming the power grid and triggering outages. Water systems experience V_JlNAmNLLN^A_LA_LNvAialApVa_]ammNmwUV]NlaALwAymA_LlAV]]V_NmAlNmqI[NJppa buckling or operational delays. In recent y NAlm!am_TN]Nmaq_pyUAmNxiNlVN_JNL severNJa_mNkqN_JNmSla^ila]a_TNLUNApNvN_pmlNV_SalJV_TpUNqlTN_p_NNLSalUNAp resilience strategies targeting both people and critical services.
Los Angeles County–1iNJVœJ^iAJpmA_LApA
x lNmVLN_pm NxiNlVN_JNL iawNl aqpATNm LqlV_T pUN qTqmp heatwave.
x ÈaSpUNaq_py¯m^V]NmaSUVTU-voltage transmission lines are exposed to moderate to high extreme heat risk.
x ^V]]Va_lNmVLN_pmAlNJa_mVLNlNLUVTU]yvq]_NlAI]NLqNpaA TNV_Ja^N LVmAIV]VpyalJUla_VJUNA]pUJa_LVpVa_m
x %vNlaqpLaalwal\NlmAlNApN]NvApNLlVm\SalUNAp -related illness and injury.
x Thousands of heat-related emergency visits occurred during multi-day heat events in 2020 and 2022especially in neighborhoods with limited shade and high surface temperatures.
x 50+ cooling centers have been activated across the County during recent heatwaves to support at-risk populations.
x VTU UNAp Ja_plVIqpNm pa walmN_NL AVl kqA]Vpy V_JlNAmNL wV]LœlN m^a\N NxiamqlNA_LNJa_a^VJ]ammNmLqNpaV_SlAmplqJpqlNLA^ATNila LqJpVvVpy LNJ]V_NA_LlVmV_TUNA]pUJAlNJampm
6.4.7 Impacts
! a m _ T N ] N m a q _ p y U A m S A J N L m V T _ V œ J A _ p A _ L T l a w V _ T V ^ i A J p m S l a^ NxplN^N UNApwAvNmavNlpUNiAmppwaLNJALNm_qTqmpAila]a_TNLUNApwAvNJAqmNL la]]V_T I]AJ\aqpm ASSNJpV_T _NAl]y
Jqmpa^Nlm avNlwUN]^N L p U N m p A p N ¯ m N]NJplVJA]TlVLA_LSa rced the activation of emergency conservation protocols. That mA^Nmq^^NlpUN1A_Nl_A_La9A]]NyUVpÑ]NALV_TpawVLN milNALmplAV_a_ County of Los Angeles
All-Hazards Mitigation Plan
HVAC systems and increased emergency room visits for heat-related illnesses. The 2022 and 2024 heatwaves brought similar conditions—temperatures over 100°F across pUNlNTVa_]NLpa]aJA]V|NLplA_mSal^NlSAV]qlNmAmiUA]pIqJ\] V_TA_LmplAV_a_wApNl delivNlymympN^mLqNpaN]NvApNLLN^A_LqlV_TpUNmNNvN_pmaqpLaalwal\NlmpUN N]LNl]yA_L]aw-income residents without access to cooling systems were among the ^ampASSNJpNLJa_a^VJAJpVvVpywAmLVmlqipNLwVpUlNialpmaS IqmV_NmmJ]amqlNm service delaymA_LV_JlNAmNLUNA]pUJAlNJampm_!a_T NAJUlNAJUNLAlNJalL
ÑJAqmV_TAmiV\NV_N]NJplVJVpyLN^A_LA_LplVTTNlV_TN^N lTN_JyN_NlTyA]Nlpm across Southern California. Heat-related deaths and hospitalizations have also trended qiwAlLiAlp icularly in neighborhoods with low tree canopy and high impervious surfaces. These impacts underscore the need for resilient infrastructure and targeted adaptation strategies to safeguard health and essential services.
6.4.8 Mitigation and Preparedness
The most effective way to reduce the negative impacts of an extreme heat event is to develop a comprehensive heat response plan that has individual strategies to effectively manage heat waves during peak seasons of the year. The plan might include SalNJAmpV_TA_L^a_VpalV_TNLqJApVa_A_LAwAlN_NmmA_LUNApwAvNlNmia_mN.
To address extreme heat!am_TN]Nmaq_pyUAmV^i]N^N_pNLmNvNlA]^NAmqlNm x Cooling Centers: Establishment of air-conditioned public spaces where residents can seek relief during heatwaves. These centers are facilities such as ]VIlAlVNm Ja^^q_Vpy JN_pNlm A_L mN_Val JN_pNlm 0NmVLN_pm JA_] a J A p N p U N nearest cooling center using resources provided by the county.
Additional
resources can be found at ŚƚƚƉƐ͗ͬͬƌĞĂĚLJ͘ůĂĐŽƵŶƚLJ͘ŐŽǀͬŚĞĂƚͬ x 4lIA_lNN_V_T_VpVApVvNm - l a T l A ^ m A V ^ N L A p V _ J l N A m V _ T T l N N _ m i A J N m i]A_pV_T plNNm A_L JlNApV_T iAl\m pa ilavVLN mUALN A_L lNLqJNA^IVN_p temperatures. These efforts help mitigate the urban heat island effect. x Public Awareness Campaigns: Educational initiatives to inform residents about UNAplVm\milNvN_pVa_mplApNTVNmA_LlNmaqlJNmAvAV]AI]NLqlV _TNxplN^NUNAp NvN_pm3UNmNJA^iAVT_mN^iUAmV|NpUNV^ialpA_JNaSUyLlApVa_ lNJaT_V|V_T heat-lN]ApNLV]]_Nmmmy^ipa^mA_LqpV]V|V_TJaa]V_g centers. x
qV]LV_TaLNmA_L0NTq]ApVa_m Incorporation of heat-mitigating designs and ^ApNlVA]mV__NwJa_mplqJpVa_mA_LlNplaœpmmqJUAmJaa]laaSm A_LlNŔNJpVvN County of Los Angeles
All-Hazards Mitigation Plan
iAvN^N_pmpalNLqJNUNApAImalipVa_3UNmN^NAmqlNmAV^pa]aw NlV_Laal temperatures and decrease reliance on air conditioning. 3UNmN mplApNTVNm AlN LNmVT_NL pa lNLqJN UNAp NxiamqlN ilapNJpvq]_NlAI]N iaiq]ApVa_mA_LN_UA_JNJa^^q_VpylNmV]VN_JNATAV_mpNxplN^NUNApNvN_pm
6.4.9 Summary
Extreme heat iamNmATlawV_TpUlNAppa!am_TN]Nmaq_pywVpUV_JlNAmV_TSlNkqN_Jy and intensity of heat waves exacerbated by urban heat island (UHI) effects.
Understanding these impacts of extreme heat A_LpA\V_TAiilailVApNilNJAqpVa_m residents of Los Angeles County can protect themselves and their communities from this growing climate hazard. 3UNJaq_pyUAmq_LNlpA\N_vAlVaqm^VpVTApVa_NSSalpm V_J]qLV_T pUN NmpAI]VmU^N_p aS Jaa]V_T JN_pNlm qlIA_ TlNN_V_Tila[NJpm iqI]VJ NLqJApVa_JA^iAVT_mA_L the implementation of heat-conscious building practices. %_TaV_TALAipApVa_A_LilaAJpVvNi]A__V_TAlNNmmN_pVA]pamASN TqAlLiqI]VJUNA]pU V_SlAmplqJpqlNA_LpUNN_vVla_^N_pSla^pUNALvNlmNNSSNJpmaSNxplN^NUNAp
County of Los Angeles
All-Hazards Mitigation Plan
6.5 Drought
6.5.1 Nature
Drought is a prolonged period of below-
average precipitation that leads to water
mUalpATNmV^iAJpV_TATlVJq]pqlNNJamympN^m
and urban water supplies. Unlike other natural
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Vp LVSœJq]p pa ilNLVJp A_L ^VpVTApN _ !am
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due to the region’s arid climate and
dependence on imported water supplies.
laqTUpmNvNlVpyVmLNpNl^V_NLIyVpmLqlApVa_
V_pN_mVpy TNaTlAiUVJ NxpN_p A_L wApNl
demand. Climate change is exacerbating these
S A J p a l m ] N A L V _ T p a U a p p N l p N ^ i N l A p q l N m lNLqJNL ilNJViVpApVa_ A_L V_JlNAmNL
evaporation rates. :V]LœlNmAlN also projected
to increase in frequency and intensity during
drought season.
3UNlNAlNSaqlJa^^a_J]AmmVœJApVa_maSLlaqTUp
x Meteorological Drought: A prolonged period of below-normal precipitation.
CCouCouuCouuntyntyntntyntynty offofofofofo LLoLLoLo AsAs As As ngenggeengelesesleslelles AAlAllAllAAAll
-
HazHHazHazardardardardddardardsMMs Ms Mss Miitiitiitiitigatgatggatiionoion PlPlPlPlPlaPlaPlalaannnnn
County of Los Angeles
All-Hazards Mitigation Plan
x Hydrological Drought: A reduction in surface and groundwater levels due to ila]a_TNLilNJViVpApVa_LNœJVpm
x Agricultural Drought: A lack of soil moisture that affects crop growth and livestock sustainability.
x Socioeconomic Drought: When water shortages impact drinking water mqii]VNmmA_VpApVa_iqI]VJmNlvVJNmA_LNJa_a^VJAJpVvVpVNm
6.5.2 Location
Drought is regional in nature and typically affects the entire Los Angeles County planning area. Given the county’s reliance on imported water from the Sierra Nevada m_awiAJ\A_LpUNa]alALa0VvNllNLqJNLAvAV]AIV]VpyaSpUNmN maqlJNmmVT_VœJA_p]y increases vulnerability.
6.5.3 Extent
laqTUpVmAlNJqllV_T_ApqlA]UA|AlLpUApJA_mNvNlN]yV^iAJpATlVJq]pqlNwApNlmqii]y NJamympN^m A_L Ja^^q_VpVNm3a ^a_Vpal A_L Ja^^q_VJApN LlaqTUpJ a _ L V p V a _ m A J l a m m p U N 4 _ V p N L 1 p A p N m p U N # A p V a _ A ] l a q T U p " V p V T A p V a _ N _ p Nl #" V_ partnership with the U.S. Department of Agriculture (USDA) and the National Oceanic A_Lp^amiUNlVJL^V_VmplApVa_#% ilaLqJNmwNN\]y41la qTUp"a_Vpal ^Aim3UNmN^AimJApNTalV|NLlaqTUpJa_LVpVa_mV_paœvN]NvN]m IAmNLa_V_pN_mVpy LqlApVa_A_LV^iAJpa_vAlVaqmmNJpalmV_J]qLV_TATlVJq]pqlN wApNllNmaqlJNmA_L public health.
AJU LlaqTUp JApNTaly lNŔNJpm A LVSSNlN_p ]NvN] aS mNvNlVpy Sla^ mUalp-term dry Ja_LVpVa_mpUAp^Aym]awJlaiTlawpUpa]a_T -pNl^wVLNmilNALwApNlmUalpATNmpUAp lNkqVlNN^NlTN_JylNmia_mN3UNmNJ]AmmVœJApVa_mUN]iLNJVmVa_-^A\NlmSAl^NlmA_L water managers respond appropriately to emerging or ongoing drought conditions.
See Figure 6.5.1 below for more information.
County of Los Angeles
All-Hazards Mitigation Plan
Drought Categories and Associated Impacts:
CATEGORY DESCRIPTION POSSIBLE IMPACTS
D4
EXCEPTIONAL
DROUGHT
x
džĐĞƉƟŽŶĂůĂŶĚǁŝĚĞƐƉƌĞĂĚĐƌŽƉͬƉĂƐƚƵƌĞůŽƐƐĞƐ
x ƌŝƟĐĂůƐŚŽƌƚĂŐĞƐŽĨǁĂƚĞƌŝŶƌĞƐĞƌǀŽŝƌƐ͕ƐƚƌĞĂŵƐ͕ĂŶĚ ǁĞůůƐ
x tĂƚĞƌĞŵĞƌŐĞŶĐŝĞƐĂŶĚƉŽƐƐŝďůĞŵĂŶĚĂƚŽƌLJƌĂƟŽŶŝŶŐ
x ^ĞǀĞƌĞŝŵƉĂĐƚƐŽŶĞĐŽƐLJƐƚĞŵƐĂŶĚǁŝůĚůŝĨĞŚĂďŝƚĂƚƐ
D3
EXTREME
DROUGHT
x DĂũŽƌĂŐƌŝĐƵůƚƵƌĂůůŽƐƐĞƐĂŶĚƉĂƐƚƵƌĞĨĂŝůƵƌĞ
x tŝĚĞƐƉƌĞĂĚǁĂƚĞƌƐŚŽƌƚĂŐĞƐ
x tĂƚĞƌƵƐĞƌĞƐƚƌŝĐƟŽŶƐůŝŬĞůLJĞŶĨŽƌĐĞĚ
x /ŶĐƌĞĂƐĞĚƌŝƐŬŽĨǁŝůĚĮƌĞƐĂŶĚŚĞĂƚ-ƌĞůĂƚĞĚƐƚƌĞƐƐ
D2
SEVERE
DROUGHT
x ƌŽƉĂŶĚƉĂƐƚƵƌĞůŽƐƐĞƐďĞĐŽŵŝŶŐůŝŬĞůLJ
x tĂƚĞƌƐŚŽƌƚĂŐĞƐďĞĐŽŵŝŶŐĐŽŵŵŽŶ
x >ŽĐĂůŐŽǀĞƌŶŵĞŶƚƐŵĂLJŝŵƉůĞŵĞŶƚǁĂƚĞƌƌĞƐƚƌŝĐƟŽŶƐ
x ,LJĚƌŽƉŽǁĞƌŐĞŶĞƌĂƟŽŶĂŶĚŝƌƌŝŐĂƟŽŶƉŽƚĞŶƟĂůůLJ
ŝŵƉĂĐƚĞĚ
D1
MODERATE
DROUGHT
x EŽƟĐĞĂďůĞĚĂŵĂŐĞƚŽĐƌŽƉƐĂŶĚƉĂƐƚƵƌĞƐ
x tĂƚĞƌůĞǀĞůƐŝŶƐƚƌĞĂŵƐĂŶĚƌĞƐĞƌǀŽŝƌƐďĞŐŝŶƚŽĚĞĐůŝŶĞ x sŽůƵŶƚĂƌLJǁĂƚĞƌ-ƵƐĞƌĞƐƚƌŝĐƟŽŶƐŵĂLJďĞƌĞƋƵĞƐƚĞĚ
x ^ŽŵĞƐƚƌĞƐƐŽŶĮƐŚĂŶĚǁŝůĚůŝĨĞƉŽƉƵůĂƟŽŶƐ
D0
ABNORMALLY
DRY
x
ĂƌůLJƐŝŐŶƐŽĨĚƌŽƵŐŚƚ͕ǁŝƚŚƐŚŽƌƚ-ƚĞƌŵĚƌLJŶĞƐƐƐůŽǁŝŶŐ ƉůĂŶƟŶŐĂŶĚĐƌŽƉŐƌŽǁƚŚ
x /ĨŝŵƉƌŽǀŝŶŐůŝŶŐĞƌŝŶŐǁĂƚĞƌĚĞĮĐŝƚƐĂƐĂƌĞĂƌĞĐŽǀĞƌƐ ĨƌŽŵĚƌŽƵŐŚƚ
x WĂƐƚƵƌĞƐŽƌǀĞŐĞƚĂƟŽŶŵĂLJƐŚŽǁƐŝŐŶƐŽĨĚĞůĂLJĞĚ
ƌĞĐŽǀĞƌLJ
Figure 6.5.1 Drought Categories and Associated Impacts
3UNmN J]AmmVœJApVa_m _ap a_]yhelp guide resources and planning but also raise awareness about the broader consequences of prolonged dryness. Understanding the extent and severity of drought helps ensure timely response and mitigation efforts at ]aJA]mpApNA_LSNLNlA]]NvN]m
County of Los Angeles
All-Hazards Mitigation Plan
6.5.4 History
!am_TN]Nmaq_pyUAmNxiNlVN_JNL^q]pVi]NmVT_VœJA_pLlaqTUpmwVpUma^N]AmpV_T several years. There have been no federal declarations or state proclamations for LlaqTUpV_pUN]AmpœvNyNAlm
Figure 6.5.2, U.S. Drought Monitor, 2025
County of Los Angeles
All-Hazards Mitigation Plan
Notable historical drought periods include:
1. 1917-1921 – A widespread drought affecting most of California.
2. 1976-1977 – One of the driest two-year periods in recorded history.
3. 1987-1992 – A six-year drought that severely impacted water supplies and agriculture.
4. 2007-2009 – A prolonged drought leading to state-imposed water restrictions.
5. 2011-2017 – 3UN ^amp mNvNlN LlaqTUp V_ ^aLNl_ UVmpaly lNmq]pV_T V_ groundwater depletion and mandatory conservation measures.
6. 2020-2022 – A]VSal_VANxiNlVN_JNLAmVT_VœJA_pLlaqTUpwVpU!am_TN]Nm aq_pyNxiNlVN_JV_T´AI_al^A]]yLly´Ja_LVpVa_m
7. 2024-2025 – Los Angeles County is continuing to experience abnormally dry Ja_LVpVa_mwVpU]awNlAverage rainfalls and arid conditions. 3UNJUAlpAIavNpUN Palmer Drought Severity Index shows how drought conditions have been changing since 1895. The Palmer Drought Severity Index measures how dry or wet an area is by comparing rainfall and temperature to long-term averages. It gives a number (positive or negative) showing drought severity or excess moisture.
Los Angeles County was in some form of drought for 376 consecutive weeks from NJN^INlq_pV]"AlJU The State and the County passed several resolutions and regulations at different times to mitigate drought impacts like water Figure 6͘ϱ͘ϯ͕EKƌŽƵŐŚƚ^ĞǀĞƌŝƚLJ/ŶĚĞdž͕ϮϬϮϰ
County of Los Angeles
All-Hazards Mitigation Plan
conservation regulations. There were no federally declared drought disasters in the AlNAV_pUNiAmpœvNyNAlmV_pUNi]A__V_TAlNA
6.5.5 Probability
Climate scientists predict that Los Angeles County and the rest of Southern California wV]]TNpLlVNlwUV]NNorthern California will get hotter. Rising temperatures contribute paUVTUNlNvAialApVa_lApNmA_LLNJ]V_V_Tm_awiAJ\V_pUN1VNll A#NvALAAJlVpVJA] source of water for Southern California. The frequency of extreme droughts is expected paV_JlNAmNlNLqJing available water resources and heightening competition between qlIA_ATlVJq]pqlA]A_LN_vVla_^N_pA]_NNLm Long-term droughts have a 100% of occurring every ten-years wVpUiapN_pVA]Sal]a_TNlA_L^alNLNmplqJpVvNLlaqTUp events due to climate change.
6.5.6 Vulnerability
Los Angeles County’s 10 million residents face growing vulnerabilities during ila]a_TNLLlaqTUpmwVpUavNl
ÈaSJa^^q_VpywApNlmympN^mNxUVIVpV_TAp]NAmpa_N
drought-lN]ApNLlVm\mqJUAmlN]VA_JNa_AmV_T]NmaqlJNalATV_TV_Sl AmplqJpqlN3UN County’s dependence on imported water—serving over 60% of residents—increases exposure to supply disruptions from reduced Sierra Nevada snowpack and Colorado River allocations. ]]lNmVLN_pmA_LvVmVpalmaSLos Angeles County are affected by water shortages during a prolonged drought conditions.
Vulnerabilities include:
x Low-income householdsaSpN_]AJ\V_TwApNl-NSœJVN_pAii]VA_JNmA_LJaa]V_T systems.
x Agricultural industry wVpUavNlAJlNmaSVllVTApNLSAl^]A_LV_pUN County is at risk of reduced water allocation and drying pastures for livestock. x Wildland-urban interface (WUI) communitieswUNlNavNl^V]]Va_lNmVLN_pm SAJNUNVTUpN_NLwV]LœlNlVm\LqNpaLlyvNTNpApVa_A_L]V^VpNLœlNœTUpV_TwApNl supply.
x Critical infrastructure operations may be impacted by a range of factors from reduced hydropower availability when reservoir levels decrease to power station cooling challenges.
County of Los Angeles
All-Hazards Mitigation Plan
These vulnerabilities illustrate the far-lNAJUV_TJlamm-sector impacts of drought on the aq_py¯mNJa_a^yN_vVla_^N_pA_L^ampAp-risk communities.
6.5.7 Impacts
%vNlpUNiAmpœvNyNAlm!am_TN]Nmaq_pyUAmNxiNlVN_JNLV_p N_mVSyV_TLlaqTUp Ja_LVpVa_m^Al\NLIylVmV_TpN^iNlApqlNmlNLqJNLm_awiAJ\A_L persistent water mUalpATNm
y
ÈaSpUNaq_py¯mJa^^q_VpywApNlmympN^mmUawNLAp]NAmpa_N LlaqTUp vq]_NlAIV]Vpy V_J]qLV_T lN]VA_JN a_ A mV_T]N wApNl maqlJN al ATV_T V_SlAmplqJpqlN-qI]VJUNA]pUV^iAJpmUAvNA]maN^NlTNLwVpUJAmNmaS9Alley fever lNialpNLV_]V_\NLpaLlymaV]A_LLqmpNxiamqlNyLlaiawNllNLqJpVa_mLqlV_T LlaqTUpiNlVaLmV_JlNAmNLlN]VA_JNa__ApqlA]TAmJa_plVIqpV_T paN]NvApNLN_NlTy JampmSallNmVLN_pm3UNmNJa^iaq_LV_TV^iAJpmUAvNmplAV_NLwA pNlmqii]yUN alth mympN^mA_LV_SlAmplqJpqlNlNV_SalJV_TLlaqTUpAmA^A[alA_LTlawV_TUA|AlLSal!am Angeles County.
6.5.8 Mitigation and Preparedness
3 aJa^IApV_JlNAmV_TLlaqTUplVm\m!am_TN]Nmaq_pyUAmV^i] N^N_pNLwApNl Ja_mNlvApVa_ia]VJVNmV_SlAmplqJpqlNV_vNmp^N_pmA_LN^NlTN_JylNmia_mN^NAmqlNm Key strategies include:
Water Management and Conservation
x Expanding water recycling and desalination programs to reduce reliance on imported water.
x Implementing drought-tolerant landscaping initiatives to lower residential and commercial water use.
x _SalJV_TwApNlNSœJVN_JylNTq]ApVa_mSal_NwLNvN]ai^N_pmA_Lupgrading older properties with water-saving strategies.
Infrastructure Improvements
x Enhancing groundwater recharge projects to increase local water storage. x Upgrading stormwater capture systems to maximize water retention during rainy seasons.
x Developing new water storage facilities to provide additional supply resilience.
Community Preparedness and Public Awareness
County of Los Angeles
All-Hazards Mitigation Plan
x Launching county-wide conservation campaigns to encourage sustainable water use.
x _JlNAmV_Tœ_A_JVA]V_JN_pVvNmSalwApNl-NSœJVN_pAii]VA_JNmA_LVllVTApVa_mympN^m x Strengthening emergency drought response plans to ensure equitable water distribution during crises.
6.5.9 Summary
Drought remains a persistent and growing threat to Los Angeles County’s water security and economic stability. Climate change projections indicate more frequent A_LmNvNlNLlaqTUpmi]AJV_TTlNApNlmplAV_a_wApNlmqii]ymympN^miqI]VJUNA]pUA_L agriculture. By implementing proactive water management mplApNTVNmV_vNmpV_TV_ V_SlAmplqJpqlN lNmV]VN_JN A_L ila^apV_T Ja^^q_Vpy AwAlN_Nmm pUN aq_py JA_ mitigate the long-term impacts of drought and ensure sustainable water resources for future generations.
County of Los Angeles
All-Hazards Mitigation Plan
Couountyty ofo Lo AAAAAAAAAAAAAAAs AsAAAAAAAAAAAAAAAAAAngengnngngnnnnngengegegegegegeengengngengnngngegggegggggggeegeggggegeeggeeeeeeeeeeeeeelesleslesllleslessesesleslesleleleslesleseseslesleseeseseselesleseseleseslleleeeeessleseeseleslessssssssessssssss AllllAlllAlAlA
-
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6.6 Flooding
6.6.1 Nature
Flooding is a persistent and increasingly severe
UA|AlL V_ !am _TN]Nm aq_py LlVvN_ Iy UNAvy
lAV_SA]]mpal^mqlTNmpal^wApNlLlAV_ATNA_LlVmV_T mNA]NvN]m3UNJaq_py¯mJa^i]NxUyLla]aTywUVJU
V_J]qLNmlVvNlmJlNN\mA_LA_NxpN_mVvNqlIA_ŔaaL
co_pla] mympN^ Vm UVTU]y mqmJNipVI]N pa avNlŔaw events when precipitation exceeds drainage capacity.
3UNNSSNJpmaSJ]V^ApNJUA_TNAlNNxAJNlIApV_TŔaaL
lVm\m Iy V_pN_mVSyV_T mpal^m A]pNlV_T ilNJViVpApVa_ iAppNl_mA_LV_JlNAmV_TmNA]NvN]m]NALV_TpaTreater JaAmpA]V_q_LApVa_A_LV_]A_LŔAmUŔaaLm
Unlike other regions that experience seasonal
ŔaaLV_TLqNpam_aw^N]pŔaaLV_TV_!am_TN]Nm
County primarily occurs during winter storms and
Ap^amiUNlVJlVvNlNvN_pmwUVJUIlV_TV_pN_mNlAV_SA]] and lightning over short periods.
x 3UNlNTVa_¯mUVTULNTlNNaSqlIA_V|ApVa_Ja_plVIqpNmpaŔAmUŔa aLV_TAmiAvNL mqlSAJNmilNvN_p_ApqlA]AImalipVa_aSwApNl]NALV_TpalAiVL lq_aSSA_LmplNNp ŔaaLV_T
County of Los Angeles
All-Hazards Mitigation Plan
x
q l _ m J A l m S l a ^ l N J N _ p w V ] L œ l N m S q l p U N l J a ^ i a q _ L Ŕ a a L l V m \ m I y lNLqJV_T vNTNpApVa_JavNlLNmpAIV]V|V_TUV]]mVLNm A_LV_JlNAmV_TpUN] V\N]VUaaLaS]A_L movement.
]aaLV_TA]maJlNApNmmNJa_LAlyUA|AlLmV_J]qLV_TNlamVa_V_S lAmplqJpqlNLA^ATN wApNlJa_pA^V_ApVa_A_LplA_mialpApVa_LVmlqipVa_m1pal^wApNllq_aSSJA_avNlwUN]^ wAmpNwApNlplNAp^N_pSAJV]VpVNm]NALV_TpaUA|AlLaqmmiV]]m! A_Lm]VLNmA_L^qLŔawm in post-wV]LœlNAlNAmiamNALLVpVa_A]lVm\mpaUa^NmlaALmA_LJlVpVJA]V_SlAmplqJpqlN 3UNmN Ja^iaq_LV_T pUlNApm UVTU]VTUp pUN qlTN_p _NNL Sal Ja^ilNUN_mVvN ŔaaL ^VpVTApVa_NSSalpmpailapNJpJa^^q_VpVNmV_SlAmplqJpqlNA_LpUNN_vVla_^N_p
6.6.2 Location
]aaLUA|AlLmAlNTNaTlAiUVJA]]ywVLNmilNALwVpU^alNpUA_mkqAlN^V]NmaS]A_L located within the 100- and 500-yNAlŔaaLi]AV_mVmpalVJA]]ymVT_VœJA_pNvN_pmmqJUAm pUNA_LŔaaLmAmwN]]Am^alNlNJN_pmpal^mV_A_LUAvNJAqmNL mqImpA_pVA]LA^ATNpaV_SlAmplqJpqlNplVTTNlNLNvAJqApVa_mA_LJUA]]N_TNL]a_T-term recovery efforts. SocVA]]yvq]_NlAI]Niaiq]ApVa_mV_J]qLV_Ta]LNlALq]pmV_LVvVLqA ]m wVpUAJJNmmA_LSq_JpVa_A]_NNLmA_L]aw -V_Ja^NUaqmNUa]LmSAJNLVmilaialpVa_ApN V^iAJpm LqN pa ]V^VpNL œ_A_JVA] lNmaqlJNm V_ALNkqApN V_mqlA_JN JavNlATN A_L reduced access to services. 3UNaq_py¯mŔaaLJa_pla]mympN^V_J]qLNmJa_JlNpNlVvNl JUA__N]m]NvNNmmpal^LlAV_mLNIlVmIAmV_mA_LlNmNlvaVlmUAmUN]iNL^VpVTApNma^N ŔaaL lVm\m Iqp lN^AV_m vq]_NlAI]N pa UVTU-intensity storms that exceed design capacities.
Major Flood-Prone Areas:
x !am_TN]Nm0VvNl1A_AIlVN]0VvNlA_L1A_pA]AlA0VvNl3UNmN^A[alwApNlwAym AlNila_NpaavNlŔawLqlV_TNxplN^Nmpal^NvN_pmiAlpVJq]Al]y LqlV_T]#V`a years.
x Ballona Creek and Malibu Creek: These urban watersheds experience rapid runoff A_LŔAmUŔaaLV_TNmiNJVA]]yV_LNvN]aiNLAlNAm
x aapUV]]m9A]]NymA_L0NJN_p
ql_1JAllNAm-amp-wV]LœlNlNTVa_mSAJNUNVTUpN_NL
lVm\aSŔAmUŔaaLmA_LLNIlVmŔawmSa]]awV_Tmpal^m
x _pN]aiN9A]]Ny_LNmNlplNTVa_mmpal^wApNliaa]mV_papN^ialAly]A\NmJAqmV_T ŔaaLNLlaALwAymA_LV_SlAmplqJpqlNLA^ATN
County of Los Angeles
All-Hazards Mitigation Plan
x Coastal Communities: Rising sea levels and storm surges threaten beachfront ilaiNlpVNmUAlIalmA_LIqmV_NmmNm
Urban areas are particularly vulnerable due to impervious surfaces and outdated LlAV_ATNmympN^mqlV_TV_pN_mNmpal^m_NVTUIalUaaLmV_aw_p aw_!am_TN]Nm 1aqpU!A_LpUN1A_Nl_A_La9A]]NySlNkqN_p]yNxiNlVN_JNmplNNpŔaaLV_TA_LplASœJ disruptia_mLN^a_mplApV_TpUN]V^VpApVa_maSNxVmpV_TV_SlAmplqJpqlNV_UA_L]V_T^aLNl_ storm events.
For a better visual representation of this Flooding Hazard within the LA County i]A__V_TAlNAi]NAmNlNSNlN_JNiiN_LVx for ŔaaLA_LV_q_LApVa_^Aim.
6.6.3 Extent
!am_TN]Nmaq_pySAJNmAmVT_VœJA_pA_LNva]vV_TŔaaLlVm\w VpUV^iAJpmlA_TV_T Sla^]aJA]V|NLqlIA_V_q_LApVa_pawVLNmilNALlVvNlV_NŔaaLV_TA_LLNmplqJpVvNLNIlVm Ŕ a w m ] p U a q T U p U N a q _ p y U A m V _ v N m p N L U N A v V ] y V _ Ŕ a a L J a _ p l a ] V_SlAmplqJpqlN inc]qLV_T A_ NxpN_mVvN _Npwal\ aS LA^m A_L LNIlVm IAmV_m pUNmN mympN^m AlN increasingly strained and cannot fully eliminate the threat. A growing number of lNmVLN_pmAlNNxiamNLpaLA_TNlaqmŔaaLV_TNAJUyNAlAmVpqApVa_^ALNwalmNIypUN limitations of aging infrastructure and the complexities of urban hydrology. Intense lAV_SA]]NvN_pmNmiNJVA]]ypUamNAmmaJVApNLwVpUAp^amiUNlVJlVvNlmAlNaJJqllV_T^alN SlNkqN_p]y A_L wVpU TlNApNl mNvNlVpy aSpN_ avNlwUN]^V_T LlAV_ATN mympN^m A_L lNmq]pV_TV_mNvNlNŔooding of streets and neighborhoods. Compounding this risk are Iql_mJAlmSla^lNJN_pwV]LœlNmwUVJUUNVTUpN_pUN]V\N]VUaaLaS^qLm]VLNmA_LLNIlVm ŔawmpUAppUlNApN_IapU]VSNA_LilaiNlpymJ]V^ApNiAppNl_mmUVSpA_LNxplN^NwNApUNl events become ^alNJa^^a_pUNŔaaLvq]_NlAIV]VpyaS!am_TN]Nmaq_pyJa_pV_qNm to deepen across its diverse geography.
Flood severity is typically measured using the 100-year and 500-yNAlŔaaLlNJqllN_JN V_pNlvA]mwUVJUV_LVJApNAÈA_LÈA__qA]ilaIAIV]VpyaSŔ aaLV_TlNmiNJpVvN]y 3UNmNLNmVT_ApVa_mTqVLNŔaaLi]AV_^A_ATN^N_pA_L^VpVTApVa_NSSalpm Key Flood Hazard Statistics in Los Angeles County:
x mkqAlN^V]Nm
È aS]A_LUAvNAÈA__qA]ŔaaLilaIAIV]Vpy
x mkqAlN^V]NmÈ UAvNAÈA__qA]ŔaaLilaIAIV]Vpy
County of Los Angeles
All-Hazards Mitigation Plan
Key Flood Hazard Statistics for Unincorporated Los Angeles County:
x mkqAlN^V]NmÈ UAvNAÈŔaaLilaIAIV]Vpy x mkqAlN^V]NmÈ UAvNAÈŔaaLilaIAIV]Vpy As climate change accelerates sea-]NvN]lVmNA_LNxplN^NlAV_SA]]NvN_pmpUNmNŔaaL - ila_NAlNAm^AyNxiA_LASSNJpV_T^alNlNmVLN_pmV_SlAmplqJpqlNA_LIqmV_NmmNm !%%"-3%#!#0
Area 0.2% Annual Flood
Probability 1% Annual Flood Probability
Los Angeles County 243.32 sq. mi. (5.11%) 4.19 sq. mi. (0.09%) Unincorporated LA County 64.77 sq. mi. (2.13%) 1.23 sq. mi. (0.04%)
6.6.4 History
!am_TN]Nmaq_pyUAmNxiNlVN_JNL_q^NlaqmmNvNlNŔaaLNvN_pm ^A_yaSwUVJU UAvNJAqmNLJApAmplaiUVJLA^ATNpaV_SlAmplqJpqlNilaiNlpyA_LUq^A_]VSN%vNlpUN LNJALNmJ]V^ApNvAlVAIV]VpylAiVLqlIA_V|ApVa_A_LA_ATV_TŔaaLJa_pla]mympN^UAvN leLpalNiNApNLŔaaLV_TLVmAmpNlm There have been no federal declarations or state ilaJ]A^ApVa_mSalNAlpUkqA\NmV_pUN]AmpœvNyNAlm
N]awAlNma^NaSpUN^ampmVT_VœJA_pUVmpalVJA]A_LlNJN_pŔaaLNvN_pmASSNJpV_TpUN region.
Notable Flood and Lightning Events in Los Angeles County:
x 1938 Los Angeles Floods%_NaSpUNLNAL]VNmpŔaaLmV_Jaq_pyUVmpalyJAqmNLIy wNN\m aS pallN_pVA] lAV_SA]] lNmq]pV_T V_ avNl LNApUm pUN LNmplqJpVa_ aS pUaqmA_LmaSUa^NmA_LwVLNmilNALV_SlAmplqJpqlNLA^ATNiAlpVJq]Al]ypaIlVLTNm and roadways.
x 1969 Winter StormsNAvylAV_m]NLpa^AmmVvNLNIlVmŔawmV_pUN1A_AIlVN] "aq_pAV_mmNvNlNqlIA_ŔaaLV_TAJlamm!am_TN]NmA_L^q]pVi]NLA^IlNAJUNm prompting major evacuations.
x 1992-1993 El Niño FloodsmNlVNmaSmpal^mplVTTNlNL]A_Lm]VLNmŔAmUŔaaLV_T A_L^A[alJaAmpA]NlamVa_wVpUmVT_VœJA_pLA^ATNpa-AJVœJaA mpVTUwAyA_L residential areas.
x :V_pNl1pal^m0-4305): Record-IlNA\V_TlAV_SA]]]NLpamVT_VœJA_pqlIA_ ŔaaLV_T laAL J]amqlNm A_L ^qLm]VLNm wVpU mNvNlN V^iAJpm AJlamm ^q]pVi]N communities.
County of Los Angeles
All-Hazards Mitigation Plan
x October 2021: Los Angeles County experienced a rare and intense thunderstorm wVpUAmVT_VœJA_pA^aq_paS]VTUp_V_T
x September 2022 Hurricane KayiAJVœJUqllVJA_NpUApJAqmNLmVT_VœJA_plAV_SA]] A]a_TwVpUlVm\aS^qLŔawmJaAmpA]ŔaaLV_TA_LJaAmpA]NlamVa_ x A_qAlyp^amiUNlVJ0VvNlvN_p0-4683): Heavy rainfall overwhelmed mpal^LlAV_mJAqmV_TmVT_VœJA_pŔaaLV_TV_a]]ywaaL A]LwV_V]]mA_L]aw-lying
V_]A_LAlNAm]NALV_TpaNvAJqApVa_mA_LV_SlAmplqJpqlNLA^ATN x NIlqAly!am_TN]Nm]aaLm0-4699): A series of intense storms caused wVLNmilNALŔAmUŔaaLV_TSlNNwAyJ]amqlNmA_L]A_Lm]VLNmLN^a _mplApV_TpUN increasing vulnerability of the county's urban areas to extreme precipitation events. x qTqmp3laiVJA]1pal^V]Aly0-4750): Several locations in the mountains of Southern California received over 10 inches of rainfall which set daily and/or ^a_pU]ylAV_SA]]lNJalLmV_^A_y]aJApVa_mV_1aqpUNl_A]VSal _VAV_J]qLV_TwVpUV_ !am_TN]Nmaq_pypA]maJlNApNLmVT_VœJA_ppUlNApaSŔAmUA_LlVvNlV_NŔaaLV_T prompted the evacuation of numerous vulnerable communities near burn scars in the region.
x NJN^INl-AJVœJ1pal^1pal^mqlTNmA_LNxplN^NJaAmpA]ŔaaLV_T]NLpa mVT_VœJA_pNlamVa_A]a_TpUNJaAmp]V_NiAlpVJq]Al]yV^iAJpV_T"AlV_ALN]0Ny!a_T
NAJUA_L9N_VJN
NAJU
x February - "AlJUp^amiUNlVJ0VvNl1pal^0 -4769): One of the most V_pN_mNlAV_SA]]NvN_pmV_lNJN_pUVmpalylNmq]pV_TV_mNvNlN ŔAmUŔaaLm^qLm]VLNm A_LiawNlaqpATNmwVpU^A_yUa^NmA_LIqmV_NmmNmmqmpAV_V_TŔaaLLA^ATN
6.6.5 Probability
]aaLlNJqllN_JNV_!am_TN]Nmaq_pyVmV_ŔqN_JNLIyIapU_ApqlA]J]V^ApNvAlVAIV]Vpy A_LpUNV_JlNAmV_TNSSNJpmaSJ]V^ApNJUA_TNVmpalVJA]]ymNvNlNŔaaLV_TVm^amp]V\N]y LqlV_Tmpla_T]#V`aNvN_pmwUVJUaJJqlAiilaxV^ApN]yNvNly payNAlmA nd can persist for several months to multiple years. These events bring elevated precipitation ]NvN]mA_LV_JlNAmNpUN]V\N]VUaaLaSIapUV_]A_LA_LJaAmpA]ŔaaLV_T mJ]V^ApNJUA_TNAJJN]NlApNmpUNSlNkqN_JyA_LV_pN_mVpyaSŔaaL-generating events AlNNxiNJpNLpaV_JlNAmNA]pNlV_TplALVpVa_A]lNJqllN_JNV_pNl vA]mA_LNxiA_LV_TpUN areas at risk. 3UNlNVmA
ÈJUA_JNaSAŔaaLV_TNvN_paJJqllV_TNAJUyNAlwVpUV_T!am Angeles County.
County of Los Angeles
All-Hazards Mitigation Plan
Key climate-related drivers include:
x Sea-!NvN]0VmN-la[NJpNLpalVmNIyV_JUNmpaavNlSNNpIy V_JlNAmV_TpUN
lVm\aSpVLA]A_Lmpal^mqlTNŔaaLV_TV_JaAmpA]Ja^^q_VpVNm x p^amiUNlVJ0VvNlvN_pm JJalLV_T pa pUN 30 pUNmN NvN_pm AlN INJa^V_T^alNSlNkqN_pA_LV_pN_mN]NALV_TpaN]NvApNLŔAmUŔa aLA_LLNIlVm ŔawlVm\m
x El Niño Cycles1pV]]NxiNJpNLNvNlypayNAlmIqpwVpUV_JlNAmNLvAlVAIV]VpyA_L mpal^V_pN_mVpypUApJA_avNlwUN]^]aJA]LlAV_ATNA_LŔaaLJa_pla]mympN^m. 3UNmN Nva]vV_T Ja_LVpVa_m JUA]]N_TN NxVmpV_T ŔaaLi]AV_ ^Aim A_L L N m V T _ Ammq^ipVa_mUVTU]VTUpV_TpUN_NNLSalALAipVvNi]A__V_TqiLAp NLlVm\^aLN]mA_L Ja_pV_qNLV_vNmp^N_pV_lNmV]VN_pV_SlAmplqJpqlNA_LŔaaL^VpVTApVa_mplApNTVNm
6.6.6 Vulnerability
!am_TN]Nmaq_pySAJNmwVLNmilNALA_L]AyNlNLvq]_NlAIV]VpVNmpaŔaaLV_TmUAiNL by a combination of environmental exposure and complex social factors. Physical vulnerability is pronounced in areas located within FEMA-designated Special Flood A|AlLlNAm1m iamp -wV]LœlNIql_mJAlmA_L]aw -lying urban drainage basins pUApAlNila_NpaŔaaLV_TawNvNlpUNLNTlNNaSlVm\VmmVT_V œJA_p]yUNVTUpN_NLSal JNlpAV_iaiq]ApVa_mwUa^Ay]AJ\pUNlNmaqlJNmalJAiAJVpypailNiAlNSallNmia_Lpa and reJavNlSla^ŔaaLNvN_pm1aJVA]]yvq]_NlAI]NTlaqimV_J]qLV_Ta ]LNlALq]pm V_LVvVLqA]m wVpU LVmAIV]VpVNm al AJJNmm A_L Sq_JpVa_A] _NNLm # ^aIV]N Ua^N lNmVLN_pmiNai]NNxiNlVN_JV_TUa^N]Nmm_NmmA_L]aw-V_Ja^NUaqmNUa]LmAlN^alN likely to reside in structurally vulnerable housing.
According to the 2021 Los Angeles County Comprehensive Floodplain Management -]A_^alNpUA_AkqAlpNlaSlNmVLN_pm]VvV_TwVpUV_pUN -yNAlŔaaLi]AV_NAl_]Nmm pUA_¸A__qA]]yq_LNlmJalV_TpUNLVmilaialpVa_ApNNJa_a^VJIqlLN_SAJNLIy those least able to absorb the costs of recovery. Climate vulnerability data further LN^a_mplApNmpUAp^AlTV_A]V|NLJa^^q_VpVNmV_ŔaaL -exposed areas face elevated lVm\mLqNpaŔaaLV_TNvN_pm3UNvq]_NlAIV]Vpy]A_LmJAiNVmSql pUNlJa^i]VJApNLIyA shortage of affalLAI]NŔaaL-lNmV]VN_pmplqJpqlNmA_LA_V_JlNAmV_T_q^INlaSlNmVLN_pm living in areas newly exposed due to climate-driven changes in precipitation and runoff patterns.
County of Los Angeles
All-Hazards Mitigation Plan
6.6.7 Impacts
Flooding in Los Angeles County leads to a broad range of direct and cascading impacts a_iNai]NV_SlAmplqJpqlNN_vVla_^N_pA_LpUNNJa_a^y3UNa q_py¯mNxpN_mVvN _Npwal\aSJlVpVJA]SAJV]VpVNmV_J]qLV_TUamiVpA]mœlNmpApVa _mwAmpNwApNlplNAp^N_p p]A_pmmJUaa]mA_LiawNlmqImpApVa_m3UNmNAlNAmSAJNlNJqll V_TNxiamqlNwVpUV_ both 100- and 500-yNAlŔaaLi]AV_mA^ATNpapUNmNSAJV]VpVNm_apa_]yJa^ila^VmNm their physical integrity but also threatens their functionality during emergency response operations.
]aaLV_TaSpN_LVmlqipm]VSN]V_NmNlvVJNmmqJUAmN]NJplVJVpy iapAI]NwApNlmA_VpApVa_ A_LplA_mialpApVa_wVpUlqlA]A_Lq_V_JalialApNLAlNAmSAJV_TpUNTlNApNmpJUA]]N_TNm palAiVLlNmpalApVa_"aIV]NUa^NmSlNkqN_p]yJa_JN_plApNLV_ ]aw-lying or under- LlAV_NL _NVTUIalUaaLm AlN NmiNJVA]]y mqmJNipVI]N pa ŔaaL LA^ATN LqN pa Ja_mplqJpVa_]V^VpApVa_mA_LV_ALNkqApNilapNJpVvN^NAmqlNm-l NvVaqmŔaaLNvN_pm UAvNlNmq]pNLV_mVT_VœJA_pLNIlVmŔawmlaALJ]amqlNmplAV_m paiiATNmA_LLA^ATN to public and private structures.
-lV^Aly9q]_NlAIV]VpVNmË^iAJpm
x %vNlmplqJpqlNmAlNNmpV^ApNLpaINLA^ATNLV_A-yNAlŔaaLNvN_pwVpU papA]LA^ATNmNxJNNLV_T¸^V]]Va_V_ilaiNlpy]ammNmV_q_ V_JalialApNL!am Angeles County.
x LLVpVa_A]]y^alNpUA_JlVpVJA]SAJV]VpVNmAlNNxiamNLV_pUN -yNAlŔaaLi]AV_
while 70 are within the 100-yNAlŔaaLi]AV_V_J]qLV_TplA_mialpApVa_AmmNpmqpV]VpVNm N^NlTN_JymNlvVJNmA_LUA|AlLaqm^ApNlVA]mSAJV]VpVNm x A 100-yNAlŔaaLNvN_pJaq]LLVmi]AJNavNlApUaqmA_LiNai]NwVpU^A_ylNkqVlV_T mUN]pNlV_TmqiialpA_LlNJavNlyNSSalpm
x iilaxV^ApN]y
pa_maSIqV]LV_T-related debris could be generated by a 100- yNAl ŔaaL NvN_p wVpU J]NA_-q i l N k q V l V _ T ^ a l N p U A _ p l q J \ ] a A L m i a m V _ T ]aTVmpVJA]N_vVla_^N_pA]A_LiqI]VJUNA]pUJUA]]N_TNm x 28.6% of households in the 100- yNAlŔaaLi]AV_AlNNJa_a^VJA]]yLVmALvA_pATNL NAl_V_Tq_LNl¸iNlyNAl]V^VpV_TpUNVlAIV]VpypaNvAJqApNlNJavNlaliAySal mitigation improvements.
x ]AlTNmUAlNaSŔaaL -prone properties are either uninsured or underinsured. The AvNlATNŔaaLV_mqlA_JNJ]AV^iAyaqpVm¸wUVJUVma_]yAIaqpÈaSpUN County of Los Angeles
All-Hazards Mitigation Plan
ŚĂƌƚƐ^ŽƵƌĐĞ͗ >ŽƵŶƚLJWƵďůŝĐtŽƌŬƐ͖ϮϬϮϭ ŽƵŶƚLJŽŵƉƌĞŚĞŶƐŝǀĞ&ůŽŽĚWůĂŶ AvNlATNlNi]AJN^N_pJampaSmplqJpqlNmV_pUNŔaaLi]AV_—V_LVJApV_TmVT_VœJA_pTAim V_œ_A_JVA]lNmV]VN_JN
x :V]LœlNIql_mJAlmA_Liamp-œlNUyLlaiUaIVJmaV]mmVT_VœJA_p]yV_JlNAmNŔaaLA_L LNIlVmŔawlVm\m iAlpVJq]Al]yV_SaapUV]]A_LJA_ya_Ja^^q_VpV Nm3UVmUA|AlL continues to grow in severity with climate-LlVvN_œlNmNAma_m
6.6.8 Mitigation and Preparedness
!am_TN]Nmaq_py¯mŔaaL^VpVTApVa_mplApNTylNLqJNmUA|AlLNx iamqlNN_UA_JNm Ja^^q_VpylNmV]VN_JNA_Lmqiialpm]a_T-term climate adaptation. Grounded in FEMA’s #ApVa_A]"VpVTApVa_lA^Nwal\A]%1 i]A__V_T TqVLA_JN A_L]aJA]ia]VJypUN County implements both structural and non-structural measures to address current and SqpqlNŔaaLlVm\malNAJpVa_mV_J]qLNlNTq]Al^AV_pN_A_JNA_LpAlTNpNLqiTlALNmpa Estimated Damage to Critical Facilities in Unincorporated Areas from 100-Year Flood Sector Number of Facilities
Affected
Average % of Total 9A]qN
Damaged
Structure Content
Safety & Security 1 7.56 10.24
Food, Water & Sheltering 9 6.72 18.73
Health & Medical 0 N/A N/A
Energy 1 23.90 47.79
Communications 0 N/A N/A
Transportation 59 1.41 8.86
Hazardous Materials 0 N/A N/A
Total/Average 70 9.90 21.40
Estimated Damage to Critical Facilities in Unincorporated Areas from 500-Year Flood Sector Number of Facilities Affected
Average % of Total 9A]qN
Damaged
Structure Content
Safety & Security 4 28.39 37.56
Food, Water & Sheltering 41 7.73 27.01
Health & Medical 0 N/A N/A
Energy 1 23.90 47.79
Communications 2 5.00 16.00
Transportation 107 3.38 19.74
Hazardous Materials 30 10.00 15.00
Total/Average 185 13.07 27.18
County of Los Angeles
All-Hazards Mitigation Plan
mpal^wApNlV_SlAmplqJpqlNlNmpalApVa_aSŔaaLi]AV_mA_LV_pNT lApVa_aSŔaaLUA|AlL data into land use planning. The County also prioritizes the protection of critical SAJV]VpVNm A_L vq]_NlAI]N UaqmV_T pUlaqTU mVpN lNplaœpm ilaiNlpy AJkqVmVpVa_ A_L e]NvApVa_ilaTlA^m-qI]VJaqplNAJUVmJa_LqJpNLpUlaqTUAIV]V_TqA]-accessible -laTlA^Sal-qI]VJ_Sal^ApVa_wUVJUila^apNmŔaaLmASNpyAwAl N_NmmN^NlTN_Jy ilNiAlNL_NmmA_LiAlpVJViApVa_V_pUN#ApVa_A]]aaL_mqlA_JN-laTlA^#- To ensure that mitigation is both data-driven and community- JN_pNlNLpUNaq_py qpV]V|NmJ]V^ApNila[NJpVa_mA_L"¯m?41^aLN]V_TpaV_Sal^V_vNmp^N_pmwUV]N coordinating with regional partners to align local actions with broader watershed strategies. Key components of the approach include:
x 4iTlALV_TJq]vNlpmLNIlVmIAmV_mA_LLlAV_ATNmympN^mpa^A_A TNV_JlNAmNL runoff
x Promoting low-impact development (LID) and incorporating green infrastructure in urban design
x Updating ordinances and the General Plan to discourage development in high-risk areas
x Maintaining inventories of repetitive loss areas and prioritizing resources for the most vulnerable populations
This comprehensive strategy ensures Los Angeles County not only meets federal and mpApNmpA_LAlLmIqpALvA_JNmŔaaLlVm\lNLqJpVa_V_AwAypUAp mASNTqAlLmiNai]N ilaiNlpyA_L_ApqlA]mympN^mSalpUNSqpqlN
6.6.9 Summary
Flooding is one of the most persistent and complex natural hazards in Los Angeles aq_pyV_pN_mVœNLIyJ]V^ApNJUA_TNqlIA_V|ApVa_A_LATV_TV_SlAmplqJpqlN3UN!am _TN]Nmaq_pylNTVa_NxiNlVN_JNmAlA_TNaSŔaaLpyiNm including stormwater lq_aSSŔAmUŔaaLV_TJaAmpA]V_q_LApVa_A_Liamp -wV]LœlNLNIlVmŔawm3UNmNNvN_pm are most common during winter storms and atmospheric river systems. High-density LNvN]ai^N_pNxpN_mVvNiAvNLmqlSAJNmA_LœlN-damaged hillsides contribute to rapid lq_aSSA_LV_JlNAmNLavNlA]]ŔaaLvq]_NlAIV]VpylNAmA]a_TIqp_ap]V^VpNLpa pUN!am _TN]Nm1A_AIlVN]A_L1A_pA]AlA0VvNlmAmwN]]AmJaAmpA ]Ja^^q_VpVNmA_L SaapUV]]lNTVa_mAlNiAlpVJq]Al]yAplVm\
County of Los Angeles
All-Hazards Mitigation Plan
Los Angeles County’s mitigation strategy is proactive and multifaceted. It includes V_SlAmplqJpqlNqiTlALNm_ApqlN-IAmNLma]qpVa_m]A_LqmNia]VJyqiLApNmA_LiqI]VJ NLqJApVa_alNilValVpVNmSaJqma_ilapNJpV_TJlVpVJA]SAJV]Vp VNmlNLqJV_TNxiamqlNV n high-lVm\UaqmV_TA_Lila^apV_TJa^^q_VpylNmV]VN_JN-]A__V_TNSSalpmAlNmqiialpNL Iy"¯m?41lVm\^aLN]V_TA_L]aJA]J]V^ApNila[NJpVa_mNmiVpNilaTlNmm^alN pUA_
lNmVLN_pmlN^AV_AplVm\Sla^^A[alŔaaLNvN_pmlNV_SalJV_TpUN_NNLfor Ja_pV_qNLV_vNmp^N_pV_Ja^ilNUN_mVvNŔaaLlVm\lNLqJpVa_AJlammpUNJaq_py
6.6.10 National Flood Insurance Program (NFIP) Repetitive Loss (RL)
JJalLV_TpapUN!am_TN]Nmaq_py-qI]VJ:al\mpUNlNAlN
0NiNpVpVvN!amm0!
properties in 28 RL areas of Unincorporated Los Angeles County as of 2025 and 8 Severe Repetitive Loss Properties (SRLP). A Repetitive Loss (RL) property is any insurable IqV]LV_TSalwUVJUpwaal^alNJ]AV^maS^alNpUA_¸wNlNiAVLIypUN#ApVa_A] Flood Insurance Program (NFIP) in any rolling 10-year period since 1978. Updated location information about RL properties in Unincorporated Los Angeles County were not avai]AI]NLqlV_TpUNLlASpV_TaSpUVmi]A_IqpVmINV_Tœ_A]V|NLA_LwV]]INV_J]qLNL in subsequent hazard mitigation efforts. Data from 2011 showed that 24 RL properties were located in the SFHA. ppUNpV^NpUN!am_TN]Nmaq_py-qI]VJ:al\mmpApNL¬pUN ^A[alVpyaSpUNlNiNpVpVvN]ammNmAlNAmmaJVApNLwVpU]aJA]V|NL qlIA_LlAV_ATNŔaaL ilaI]N^mNvN_SalilaiNlpVNmwVpUV_A"-LNmVT_ApNLŔaaL|a_N3UN!am_TN]Nm County Public Works oversees RL mitigation projects.
County of Los Angeles
All-Hazards Mitigation Plan
CouCouCouCouCoCouCouCouCouCououuouCououCoCouCooCCCouCCCCCCCountyntyntyntynntntyntyntytyttytyntynttntyntyntyntyyyyyyyyyyyy ofofofofofofofofofoffooofofofofffffofofofoffofoofof LoLoLoLoLoLoLLoLoLoLoLoLoLoLoLoLoooLooLoLoooLoLoLoLoooooooooLLLooLoooLLL ss As As As As As As AAsAs AsAsAs As As As AAsAs AssAss AsAs AssAss AAssssss Asssss As s Angngengengngengengengegegegeegeengngengegggeengengegengeengegengengengengegengeengegeengeng lesleslesleslesleslessleseseseslesleslesleslelleselesleslesleslesleseselleleslesesssssssslesleleseessssleslesl sleesseslesssesssess AAAllAllAllAlAllAllAllAlAllAllAllAllAAAAAAAAAlAAAlllllAAAAAAAAAAAllAllAAAAAAAlAlAllllAAllAAAAAllllAAAAAAAlll ----------------
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6.7 Dam Failure
6.7.1 Nature
Dam failure refers to the structural collapse of a
dam that results in the sudden and uncontrolled
release of stored water. Such failures can occur
due to age- lN]ApNL LNpNlValApVa_ V_ALNkqApN
miV]]wAy JAiAJVpy mplqJpqlA] LA^ATN Sla^
mNVm^VJ AJpVvVpy al ŔaaLV_T A_L iaal
maintenance. The catastrophic release of water
from a dam failure has the potential to cause
human JAmqA]pVNmmVT_VœJA_pNJa_a^VJ]ammA_L
environmental destruction. This type of disaster
is particularly dangerous because it can occur
mqLLN_]y]NAvV_T]Vpp]NpV^NSalNvAJqApVa_al
emergency response efforts.
3UN^AT_VpqLNaSŔaaLV_TSla^LA^ SAV]qlN
often exceeds the capacity of downstream
JUA__N]m JAqmV_T lAiVL V_q_LApVa_ aS
mqllaq_LV_T AlNAm3UVm ŔaaLV_T JA_ ]NAL pa
NxpN_mVvN ilaiNlpy LA^ATN NlamVa_
V_SlAmplqJpqlNLNmplqJpVa_A_LJa_pA^V_ApVa_aS
watelmqii]VNmLLVpVa_A]]ymNJa_LAlyUA|AlLm
m q J U A m ] A _ L m ] V L N m A _ L L N I l V m Ŕ a w m J A _ I N plVTTNlNLJa^iaq_LV_TpUNLVmAmpNl¯mV^iAJp
The structural stress on dams may rise as dams
ATNA_LJ]V^ApNvAlVAIV]VpyV_JlNAmNmpUNSlNkqN_JyaSNxplN^N ilNJViVpApVan events.
Planning efforts include both dams and debris basins. To simplify language of the plan both reservoir dams and storm water debris basins will be referred to as dams.
County of Los Angeles
All-Hazards Mitigation Plan
6.7.2 Location
Los Angeles County has over 90 dams regulated by the California Department of Water Resources’ Division of Safety of Dams (DSOD). Fifteen (15) of these dams and eighteen (18) debris basins are owned and operated by the Los Angeles County Public Works -: _pUNA]VSal_VA!NTVm]ApqlN^A_LApNLpUApA]]mpA pN-jurisdictional dams NxJ]qLV_TpUamNJ]AmmVœNLAm!awA|AlL LNvN]aiLA^IlNAJUV_q_LApVa_^AimA_L Emergency Action Plans (EAPs) approved by DSOD and Cal OES. "A_yaSpUNmNLA^mAlN]aJApNL_NAlUVTU]yiaiq]ApNLAlNAmV_JlNAmV_TpUNiapN_pVA] for human and economic impacts during a failure event. Seventy (70) dams are J]AmmVœNLAmVTUalxplN^N]yVTUUA|AlLiapN_pVA]LA^m^NA_V_TpUNVlSAV]qlNJaq]L resultV_mVT_VœJA_p]ammaS]VSNA_LwVLNmilNALilaiNlpyLA^ATN 3UN:UVppVNl#AllawmA^lNJ]AmmVœNLAmpUN41l^yalimaS_TV_NNlm¯41 highest-ilValVpyLA^mASNpyJa_JNl_iamNma_NaSpUNTlNApNmplVm\mLqNpaVpmiapN_pVA] p a Ŕ a a L U V T U ] y i a i q ] A p N L A l N A m S l a ^ - V J a 0 V v N l A p a ! a _ T N A J U 41 UAm
determined that an extreme storm event has a 1 in 900 (0.1%) chance of causing catastrophic failure annually. Mitigation actions related to County-owned dams are prioritized based on their hazard level and potential to impact populated areas.
For a better visual representation of this Dam Failure Hazard within the LA County i]A__V_TAlNAplease reference Appendix A for all the County owned dams and debris basins maps.
6.7.3 Extent
The Federal Guidelines for Inundation Mapping of Flood Risks Associated with Dam Incidents and Failures (FEMA P- JApNTalV|Nm LA^ UA|AlLm V_pa Saql J]AmmVœJApVa_m
x Low Hazard"V_V^A]LA^ATNNxiNJpNL_a]ammaS]VSN x 1VT_VœJA_pA|AlL: Potential for property damage and economic disruption. x High Hazard!V\N]ypalNmq]pV_]ammaS]VSNA_LmVT_VœJA_pLA^ATNpaJlV pVJA] infrastructure.
x xplN^N]yVTUA|AlL1%]AmmVœJApVa_ : Could cause large-scale fatalities A_LV_q_LApNAlNAmwVpUavNllNmVLN_pm
VvN_pUNiaiq]ApVa_LN_mVpyaS!am_TN]Nmaq_pyALA^SAV]qlNJ]AmmVœNLAmVTUal xplN^N]yVTUA|AlLwaq]L]V\N]yJAqmNmqImpA_pVA]Uq^A_JAmqA]pVNmLVmi]AJNN_pVlN Ja^^q_VpVNmA_LV_ŔVJpmNvNlNNJa_a^VJA_LN_vVla_^N_pA]LA^ATNTable 6-3 and 6-4 below shows a list of dams and debris basins owned by PW along with their hazard J]AmmVœJApVa_m-apN_pVA]^VpVTApVa_AJpVa_mLNmJlVINLV_pUVm"-AlNa_]yAii]VJAI]N to the dams and debris basins owned by PW and implementation of these actions are the responsibility of the PW Stormwater Engineering Division – Dams Section.
County of Los Angeles
All-Hazards Mitigation Plan
Table 6-3: Los Angeles County PW Dam Hazard Status
Dam Name Hazard Status >ŽĐĂƟŽŶ
ŝŐĂůƚŽŶ
džƚƌĞŵĞůLJ,ŝŐŚ 'ůĞŶĚŽƌĂ͕
ŝŐ^ĂŶƚĂŶŝƚĂ
džƚƌĞŵĞůLJ,ŝŐŚ DŽŶƌŽǀŝĂ͕
ŝŐdƵũƵŶŐĂEŽ͘ϭ
džƚƌĞŵĞůLJ,ŝŐŚ dƵũƵŶŐĂ͕
ŽŐƐǁĞůů
džƚƌĞŵĞůLJ,ŝŐŚ njƵƐĂ͕
ĞǀŝůƐ'ĂƚĞ
džƚƌĞŵĞůLJ,ŝŐŚ >ĂŶĂĚĂ&ůŝŶƚƌŝĚŐĞ͕
>ŝǀĞKĂŬ
džƚƌĞŵĞůLJ,ŝŐŚ >ĂsĞƌŶĞ͕
DŽƌƌŝƐ
džƚƌĞŵĞůLJ,ŝŐŚ njƵƐĂ͕
WĂĐŽŝŵĂ
džƚƌĞŵĞůLJ,ŝŐŚ WĂĐŽŝŵĂ͕
WƵĚĚŝŶŐƐƚŽŶĞ
džƚƌĞŵĞůLJ,ŝŐŚ ^ĂŶŝŵĂƐ͕
WƵĚĚŝŶŐƐƚŽŶĞŝǀĞƌƐŝŽŶ ,ŝŐŚ >ĂsĞƌŶĞ͕
^ĂŶŝŵĂƐ
džƚƌĞŵĞůLJ,ŝŐŚ >ĂsĞƌŶĞ͕
^ĂŶ'ĂďƌŝĞůEŽ͘ϭ
džƚƌĞŵĞůLJ,ŝŐŚ njƵƐĂ͕
^ĂǁƉŝƚ
džƚƌĞŵĞůLJ,ŝŐŚ DŽŶƌŽǀŝĂ͕
^ŝĞƌƌĂDĂĚƌĞ ,ŝŐŚ ^ŝĞƌƌĂDĂĚƌĞ͕
dŚŽŵƉƐŽŶƌĞĞŬ
džƚƌĞŵĞůLJ,ŝŐŚ ůĂƌĞŵŽŶƚ͕
Table 6-4: Los Angeles County PW Debris Basin Hazard Status Debris Basin Name Hazard Status >ŽĐĂƟŽŶ
ĂŝůĞLJĞďƌŝƐĂƐŝŶ ,ŝŐŚ ^ŝĞƌƌĂDĂĚƌĞ͕
ŝŐĂůƚŽŶĞďƌŝƐĂƐŝŶ ,ŝŐŚ 'ůĞŶĚŽƌĂ͕
ůĂŶĐŚĂƌĚĞďƌŝƐĂƐŝŶ ,ŝŐŚ dƵũƵŶŐĂ͕
ƌĂŶĚĞďƌŝƐĂƐŝŶ ,ŝŐŚ 'ůĞŶĚĂůĞ͕
ĂƚŽŶtĂƐŚĞďƌŝƐĂƐŝŶ
džƚƌĞŵĞůLJ,ŝŐŚ WĂƐĂĚĞŶĂ͕
>ĂdƵŶĂĞďƌŝƐĂƐŝŶ
džƚƌĞŵĞůLJ,ŝŐŚ ^ƵŶsĂůůĞLJ͕
>ĂŐƵŶĂZĞŐƵůĂƟŶŐĂƐŝŶ ^ŝŐŶŝĮĐĂŶƚ ůŚĂŵďƌĂ͕
>ŝƩůĞĂůƚŽŶĞďƌŝƐĂƐŝŶ
džƚƌĞŵĞůLJ,ŝŐŚ 'ůĞŶĚŽƌĂ͕
>ŽǁĞƌ^ƵŶƐĞƚĞďƌŝƐĂƐŝŶ ,ŝŐŚ ƵƌďĂŶŬ͕
DŽƌŐĂŶĞďƌŝƐĂƐŝŶ ,ŝŐŚ 'ůĞŶĚŽƌĂ͕
ZƵďŝŽĞďƌŝƐĂƐŝŶ ,ŝŐŚ ůƚĂĚĞŶĂ͕
^ĂŶƚĂŶŝƚĂĞďƌŝƐĂƐŝŶ >Žǁ ƌĐĂĚŝĂ͕
^ĂǁƉŝƚĞďƌŝƐĂƐŝŶ
džƚƌĞŵĞůLJ,ŝŐŚ DŽŶƌŽǀŝĂ͕
County of Los Angeles
All-Hazards Mitigation Plan
Debris Basin Name Hazard Status >ŽĐĂƟŽŶ
^ĐŚŽŽůŚŽƵƐĞĞďƌŝƐĂƐŝŶ ,ŝŐŚ >ŽƐŶŐĞůĞƐ͕
^ŝĞƌƌĂDĂĚƌĞsŝůůĂ
džƚƌĞŵĞůLJ,ŝŐŚ ^ŝĞƌƌĂDĂĚƌĞ͕
^ƚĞǀĞŶƐŽŶZĂŶĐŚ ,ŝŐŚ ^ƚĞǀĞŶƐŽŶZĂŶĐŚ͕
^ƚŽƵŐŚĞďƌŝƐĂƐŝŶ
džƚƌĞŵĞůLJ,ŝŐŚ ƵƌďĂŶŬ͕
tŝůƐŽŶĞďƌŝƐĂƐŝŶ ,ŝŐŚ >ŽƐŶŐĞůĞƐ͕
6.7.4 History
Los Angeles County has experienced one of the deadliest dam failures in U.S. history:
x St. Francis Dam Failure (March 12-
o Released 12.4 billion gallons of water
o At least 411 fatalities
o Devastated towns from San Francisquito Canyon to Ventura County o Resulted in sweeping changes to California dam safety regulations and the creation of state oversight for civil engineers
:UV]N_a^A[alLA^SAV]qlNmUAvNaJJqllNLV_lNJN_pLNJALNmJa _JNl_mavNlATV_T LA^V_SlAmplqJpqlNmNVm^VJlVm\mA_LV_JlNAmV_TJ]V^ApNvAlVAIV]VpyUAvNlAVmNLA]Al^m AIaqpSqpqlNlVm\m1pqLVNmV_LVJApNpUAp^A_yA]VSal_VALA^m V_J]qLV_TpUamNV_!am _TN]Nm aq_py lNkqVlN mplqJpqlA] qiLApNm pa wVpUmpA_L ^aLNl_UyLla]aTVJA] conditions and potential seismic activity. There have been no federal declarations or mpApNilaJ]A^ApVa_mSalLA^SAV]qlNV_pUN]AmpœvNyNAlm
6.7.5 Dam Coordination
Los Angeles County Public Works JaalLV_ApNmwVpU]aJA]mpApNA_LSNLNlA]ATN_JVNmpa ^VpVTApNŔaaLlVm\UA|AlLmpaLaw_mplNA^Ja^^q_VpVNmSla^VpmLA^mppUN]aJA]]NvN] PW works with cities and public agencies during development of Emergency Action -]A_m- 3UVmilavVLNm]aJA]mpA\NUa]LNlmwVpUpUNaiialpq_ VpypalNvVNwpUN- ilavVLNSNNLIAJ\A_LJa_œl^lNmia_mVIV]VpVNmA_Lla]NmLqlV_T A_-AJpVvApVa_p request from local [qlVmLVJpVa_m PW ^AyilavVLNpaqlmaSVpmLA^SAJV]VpVNmwUNlN information on dam safety and the potential hazards associated with dam failures are shared.
ppUNmpApN]NvN]PW works with the DSOD to meet compliance with state dam safety mpA_LAlLmA_LŔaaL^A_ATN^N_pApA]]aS PW’s dams. This includes annual dam County of Los Angeles
All-Hazards Mitigation Plan
V_miNJpVa_mlNvVNwAiilavA]A_LavNlmVTUpaSLA^Ja_mplqJpVa _ila[NJpmlNvVNwaS LA^mASNpy^a_VpalV_TA_LavNlmVTUpaSapUNlLA^mASNpylNTq]ApalyAJpVvVpVNmPW also JaalLV_ApNmwVpUvAlVaqmmpApNATN_JVNmV_J]qLV_T1%A]%1A_LA]plA_mLqlV_T development of EAPs.
ppUNSNLNlA]]NvN]PW works with the Federal Energy Regulatory Commission (FERC) pa^NNpJa^i]VA_JNwVpUmpApNLA^SNLNlA]mpA_LAlLmA_LŔaaL^A_ATN^N_pApPW’s 1A_ AIlVN] A^ wUVJU Vm q_LNl 0 [qlVmLVJpVa_ 3UVm V_J]qLNm A__qA] LA^ V_miNJpVa_mlNvVNwAiilavA]A_LavNlmVTUpaSLA^Ja_mplqJpVa _ila[NJpmlNvVNwaS LA^mASNpy^a_VpalV_T-JaalLV_ApVa_A_LavNlmVTUpaSapUNlLA^mASNpylNTq]Apaly activities. PW also coordinates with the United States Army Corps of Engineers (USACE) on operations of interconnected dam facilities and emergency response planning for USACE facilities that may be in the pathway of dam failure impacts.
Information Sharing
PW ilavVLNmJlVpVJA]V_Sal^ApVa_palN]NvA_p]aJA]mpApNA_LSNL NlA]mpA\NUa]LNlmpa address hazard mitigation related to dam safety. This includes:
x Emergency Action Plans (EAPs): -maqp]V_NpUNla]NmlNmia_mVIV]VpVNmA_L procedures to follow in the event of a dam emergency. The EAPs include V_q_LApVa_^AimwUVJUmUawAlNAmpUApwaq]LINASSNJpNLIyAL A^SAV]qlN helping to identify populations at risk. These plans are shared with stakeholders to ensure a coordinated response. Due to the sensitive nature of information Ja_pAV_NLwVpUV_pUN-mpUNyAlNJa_œLN_pVA]A_L_aplN]NAmNLpapUNTN_NlA] public.
x Inundation Maps: Inundation maps are critical tools for identifying areas and populations at risk in the event of a dam failure. They also indicate potential V^iAJpm a_ JlVpVJA] V_SlAmplqJpqlN SAJV]VpVNm mqJU Am UamiVpA]m mJUaa]m A_L transportation networks. These maps are shared with relevant stakeholders recognized in the EAP and are available to the general public through the DSOD Dam Breach Inundation Map Web Publisher.
6.7.6 Probability
Los Angeles County contains over 90 state-[qlVmLVJpVa_A]LA^mwVpUAiilaxV^ApN]y J]AmmVœNLAmVTUalxplN^N]yVTUA|AlLIypUNA]VSal_VAVvVmVa_aS1ASNpyaSA^m 1% ^NA_V_TpUNVlSAV]qlNJaq]LlNmq]pV_]ammaS]VSNA_L mVT_VœJA_pilaiNlp y damage.
County of Los Angeles
All-Hazards Mitigation Plan
]pUaqTUJa^ilNUN_mVvNSAV]qlNilaIAIV]VpVNmAlN_apiqI]VmUNL SalNAJULA^" and DSOD guidance suggest that the general annual probability of failure for High A|AlLLA^m_ApVa_wVLNlA_TNmSla^ÈpaÈalV_ paV_ depending on ^AV_pN_A_JNATNmNVm^VJvq]_NlAIV]VpyA_LapUNlmVpN-miNJVœJSAJpalm Applying this range to Los Angeles County:
x 3UNATTlNTApNA__qA]ilaIAIV]VpyaSAmVT_VœJA_pLA^SAV]qlNNv N_pV_pUN county—across one or more of the 70 high-risk dams—is estimated at between ÈA_L
ÈA__qA]]ySAJpalV_TJq^q]ApVvNNxiamqlNA_LLVSSN lN_pUA|AlL J]AmmVœJApVa_m1qJUAmNAlpUkqA\NalŔaaLlN]ApNL
x ]V^ApNJUA_TNATV_TV_SlAmplqJpqlNA_LmNVm^VJAJpVvVpyV_!am_TN]Nmaq_py increase systemic risk across multiple structures simultaneously. _mq^^AlywUV]NpUNV_LVvVLqA]]V\N]VUaaLaSSAV]qlNSalA_y a_NLA^VmvNly]awpUN overall countywide probability of at least one major dam failure event is low but still wAllA_pmJa_pV_qNLvVTV]A_JN^AV_pN_A_JNA_LN^NlTN_Jyi]A__V_T
6.7.7 Vulnerability
A catastrophic dam failure in Los Angeles County could have severe consequences for Uq_LlNLmaSpUaqmA_LmaSlNmVLN_pm3UNLN_mN]yiaiq]ApNL_Apql NaSpUNJaq_py combined with the location of several large dams near residential and commercial AlNAmV_JlNAmNmpUNiapN_pVA]SalwVLNmilNALLVmi]AJN^N_p]ammaS]VSNA_LNJa_a^VJ LA^ATN3UN30VLN_pVœNm^q]pVi]NUVTU -risk zones where dam failure could lNmq]pV_NxpN_mVvNŔaaLV_TA_L^AmmNvAJqApVa_m
x High-lVm\LA^mA^a_TapUNlmiamNAmVT_VœJA_ppUlNAppaLN_mN]yia iq]ApNL communities. A breach in any of these dams could inundate entire _NVTUIalUaaLmASSNJpV_T^alNpUA_
lNmVLN_pmV_]aw -lying areas and
ŔaaLi]AV_m
x 1aJVA]]y vq]_NlAI]N iaiq]ApVa_m V_J]qLV_T N]LNl]y V_LVvVLqA]mp U N # Ja^^q_VpyiNai]NNxiNlVN_JV_TUa^N]Nmm_Nmm]aw-V_Ja^NJa^^q_VpVNmA_L non-English-speaking residents face heightened risks during evacuations and lNJavNlyLqNpa]V^VpNL^aIV]Vpyœ_A_JVA]Ja_mplAV_pmA_LAJJNmmpalNmaqlJNm x LqJApVa_A]A_LUNA]pUJAlNV_mpVpqpVa_mAlNAplVm\wVpUmNvNlA]mJUaa]mUamiVpA]m and long-pNl^JAlNSAJV]VpVNm]aJApNLV_ŔaaL -prone areas. A major dam failure Jaq]LlNmq]pV_mJUaa]J]amqlNmLVmi]AJN^N_paSmpqLN_pmA_L LVmlqipVa_aS healthcare services.
County of Los Angeles
All-Hazards Mitigation Plan
x vAJqApVa_A_LN^NlTN_JymUN]pNlV_TLN^A_Lmwaq]LINmqImpA_pVA]lNkqVlV_T the rapid mobilization of resources to support displaced residents. Temporary mUN]pNlmN^NlTN_Jy^NLVJA]mNlvVJNmA_L logistical support would need to be activated to accommodate evacuees.
!am_TN]Nmaq_pylN]VNmUNAvV]ya_LA^mA_LlNmNlvaVlmSalwA pNlmpalATNŔaaL Ja_pla]A_Lmqii]ylNTq]ApVa_ApAmplaiUVJLA^SAV]qlNiamNm A_AJqpNpUlNAppa]VSN A_LilaiNlpyNmiNJVA]]yV_]aw-]yV_TUVTU]yiaiq]ApNLLaw_mplNA^AlNAm Extent of Exposure
x Total Area Exposed: 490.64 sq mi
x Supervisorial Districts (SD) Impacted:
o SD5: 223.88 sq mi (7.97%)
o SD1: 162.25 sq mi (45.98%)
o SD2: 66.57 sq mi (18.32%)
o SD3: 25.76 sq mi (5.97%)
o SD4: 12.17 sq mi (5.72%)
x Critical Facilities Affected:
o Fire Department: 112 (33.22%)
o Public Works: 92 (40.00%)
o Health Services: 29 (44.62%)
o Public Health: 17 (42.50%)
o Libraries: 30 (34.48%)
o Parks: 65 (35.50%)
o Education: 34 (41.46%)
Problem Statement
Dam SAV]qlNwUV]NlAlNJA_UAvNJApAmplaiUVJJa_mNkqN_JNmV_LN_m N]yiaiq]ApNL Law_mplNA^ AlNAm :VpU mVT_VœJA_p ialpVa_m aS JlVpVJA] V_SlAmplqJpqlN NxiamNL— particularly in SD1 and SD5— i]A__V_T Sal N^NlTN_Jy NvAJqApVa_m NAl]y wAl_V_T mympN^mV_SlAmplqJpqlNUAlLN_V_TA_LLaw_mplNA^LNvN]ai^N_plNTq]ApVa_VmJlVpVJA] to saving lives and reducing loss.
County of Los Angeles
All-Hazards Mitigation Plan
A failure or breach of a High Hazard Potential Dam (HHPD) in Los Angeles County waq]LlNmq]pV_JApAmplaiUVJJa_mNkqN_JNmSalLaw_mplNA^Ja^^q_ VpVNmwVpUpUN greatest vulnerabilities concentrated in densely populated urban areas. Rapid and ^AmmVvN ŔaaLV_T waq]L ]V\N]y V_q_LApN lNmVLN_pVA] _NVTUIalUaaLm Ja^^NlJVA] LVmplVJpmA_LV_LqmplVA]|a_NmwVpUV_^V_qpNmpaUaqlmLNiN_L V_Ta_ilaxV^VpyA_L topography. Critical infrastructure—V_J]qLV_TUamiVpA]mœlNA_Lia]VJNmpApVa_mmJUaa]m and major transportation corridors— waq]L IN mNvNlN]y V^iAJpNL LVmlqipV_T N^NlTN_JymNlvVJNmA_LNvAJqApVa_laqpNm3UaqmA_LmaSiNai]NV_J]qLV_Tvq]_NlAI]N iaiq]ApVa_mmqJUAmpUamNwVpUJJNmmA_Lq_JpVa_A]#NNLm# N]LNl]ylNmVLN_pm and low- V_Ja^N UaqmNUa]Lm wauld face immediate life- pUlNApN_V_T Ja_LVpVa_m LVmi]AJN^N_pA_L]V^VpNLAJJNmmpa^NLVJA]JAlNalmUN]pNlJa_a^VJ]ammNmwaq]LIN Ja^iaq_LNLIyLA^ATNpaqpV]VpVNmV_J]qLV_TiawNlmqImpApVa_m A_LwApNlmympN^m potentially leaving large swaths of the region without essential services. The sheer scale aSLNvAmpApVa_Sla^ALA^SAV]qlNNmiNJVA]]yApSAJV]VpVNmmqJ UAm:UVppVNl#Allawmal AmpAVJA^q_LNlmJalNmpUNJlVpVJA]V^ialpA_JNaSJa_pV_qNLl Vm\lNLqJpVa_NAl]y wAl_V_TmympN^mA_LLA^lNUAIV]Vtation efforts.
6.7.8 Data Limitations
A limitation of this AHMP is that planning efforts only covered PW-owned dams in Los Angeles County. Future mitigation planning should include other dam owners and operators in Los Angeles County such as the US Army Corps of Engineers. The data on high-hazard dams reviewed during the 2025 AHMP planning process was generally suitable for the analysis required. Future opportunities for obtaining additional data to be considered in the next update to the plan should:
x Incorporate more current information as it becomes available. x Assess any new or updated EAPs for dams owned by Los Angeles County. x Identify and review more current structural or condition assessment data to inform future risk assessments.
x Involve other dam owners within Los Angeles County in future planning efforts.
6.7.9 Impacts
A dam failure in Los Angeles County would have catastrophic and immediate Ja_mNkqN_JNmSal]VSNilaiNlpyA_LJlVpVJA]V_SlAmplqJpqlNi AlpVJq]Al]yV_pUNLN_mN]y populated downstream areas. The sudden release of impounded water from a High or Extremely HVTUA|AlLLA^Jaq]LV_q_LApN_NVTUIalUaaLmwVpUV_^V_qpNmA]] awV_T ]Vpp]Npa_apV^NSalNvAJqApVa_"alNpUA_
lNmVLN_pm]VvNwVpUV_VLN_pVœNLLA^
V_q_LApVa_|a_Nm^A_yaSwUa^AlNV_maJVA]]yvq]_NlAI]Niaiq] ApVa_m—including County of Los Angeles
All-Hazards Mitigation Plan
V_LVvVLqA]mwVpU]V^VpNL^aIV]Vpy]aw -V_Ja^NUaqmNUa]LmA_LiNai]NNxiNlVN_JV_T homelessness—making rapid evacuation and sheltering especially challenging.
County-owned high hazard potential dams and their locations are listed in Table 6-3.
Inundation maps for County-owned high hazard potential dams are listed in Appendix A-7.
Critical infrastructure is also at mVT_VœJA_plVm\amiVpA]mœlNmpApVa_m]AwN_SalJN^N_p SAJV]VpVNmN^NlTN_JyaiNlApVa_mJN_pNlmmJUaa]mA_LwAmpNwAp NlplNAp^N_pi]A_pm ]aJApNLV_Law_mplNA^|a_Nm^AyINLA^ATNLallN_LNlNLV_aiNlAI ]NmNvNlN]y disrupting emergency response and life-sustaining services. Major transportation laqpNmmqJUAmV_pNlmpApNmlAV]]V_NmA_LAlpNlVA]laALmJaq]LINmqI^NlTNLalwAmUNL aqpV^iNLV_TlNmJqNA_LlNJavNlyNSSalpmLLVpVa_A]]yiawNl mqImpApVa_mwApNl LVmplVIqpVa__Npwal\mA_LpN]NJa^^q_VJApV ons infrastructure could suffer cascading SAV]qlNmJa_plVIqpV_TpawVLNmilNALaqpATNmA_Lila]a_TNLlNJavNlyiNlVaLm The economic consequences of dam failure would be immense. Beyond property LA^ATN IqmV_Nmm aiNlApVa_m V_ V_q_LApNL AlNAm waq]L UA]p ]NALV_T pa ]amm aS N^i]ay^N_ppAxlNvN_qNA_LNJa_a^VJAJpVvVpy_LqmplVA]|a_NmNmiNJVA]]ypUamN_NAl ^A[al ŔaaL Ja_trol reservoirs or channels) could potentially release hazardous ^ApNlVA]mVSavNlwUN]^NLiamV_TmNJa_LAlyN_vVla_^N_pA]A_LiqI]VJUNA]pUUA|AlLm NIlVm AJJq^q]ApVa_ mNLV^N_pApVa_ A_L Ja_pA^V_ApVa_ Jaq]L mNvNlN]y V^iAJp NJamympN^mwApNlkqA]VpyA_LŔaaLJa_pla]V_SlAmplqJpqlNLaw_mplNA^Ja^i]VJApV_T both emergency cleanup and long-term environmental recovery. VvN_pUNmJA]NaSiapN_pVA]V^iAJpmLA^SAV]qlNVmJa_mVLNlNLAmpAI]N]aw-probability but high-Ja_mNkqN_JNUA|AlLV_!am_TN]Nmaq_pylNkqVlV_TJa_pV_qNLV_vNmp^N_p V_mplqJpqlA]^VpVTApVa_N^NlTN_JyilNiAlNL_NmmA_LiqI]VJAwAlN_NmmpalNLqJNpUN severity of its effects.
6.7.10 High Hazard Potential Dams Goals
aA] _UA_JNlNmV]VN_JNAJlammLA^LNIlVmIAmV_V_SlAmplqJpqlNV_J] qLV_TUVTU - UA|AlLiapN_pVA]LA^mA_LapUNlJlVpVJA]SAJV]VpVNmwVpUV_LA^V_q_LApVa_|a_Nm aA]Encourage structural reinforcement or lNplaœpmSalATV_TA_Lvq]_NlAI]NLA^m aA]Ensure all dams/ debris basins have updated Emergency Action Plans (where applicable) and updated dam inundation mapping consistent with state standards.
County of Los Angeles
All-Hazards Mitigation Plan
6.7.11 Mitigation and Preparedness
Los Angeles County and state agencies have implemented various mitigation efforts to reduce the risks associated with dam failures:
x 1plqJpqlA]0NV_SalJN^N_pm4iTlALV_TmiV]]wAymmplN_TpUN_V_TNAlpUN_LA^m A_LV^i]N^N_pV_TmNVm^VJlNplaœppV_T^NAmqlNm
x Emergency Action Plans (EAPs): M a n d a t e d b y D S O D f o r a l l H i g h a n d Extremely High hazard dams to guide evacuation and response efforts. x Early Warning Systems: ^ilavNL ŔaaL ^a_VpalV_T A_L Aqpa^ApNL A]Nlp systems to notify at-risk communities in real-time.
6.7.12 High Hazard Potential Dam Prioritization
The risk assessment within the 2025 AHMP considers the county planning area’s vulnerability and potential impacts related to HHPDs. Mitigation actions and planning efforts that are related to mitigating long-term vulnerabilities to County-owned HHPDs will automatically be given a HIGH priority as described in the overall mitigation action prioritization criteria in Section 7.6. The County Departments responsible for V^i]N^N_pV_TpUNAmmaJVApNL^VpVTApVa_AJpVa_mA]a_TwVpUpUN ilValVpyiapN_pVA] funding saqlJNA_LNxiNJpNLpV^NSlA^NAlN]VmpNLV_1NJpVa_
6.7.13 Summary
Los Angeles County has 90 state- [qlVmLVJpVa_A]LA^mwVpUJ]AmmVœNLAmVTUal xplN^N]yVTUUA|AlL^NA_V_TpUNVlSAV]qlNJaq]LlNmq]pV_wVLNmilNAL]ammaS]VSNA_L NJa_a^VJLNvAmpApVa_:UV]NlNTq]ApalyavNlmVTUpUAmV^ilavNLL A^mASNpyATV_T infrA m p l q J p q l N m N V m ^ V J p U l N A p m A _ L V _ J l N A m N L m p a l ^ V _ p N _ m V p y l N ^ AV_ JUA]]N_TNm a_pV_qNLV_vNmp^N_pV_lNplaœpmNAl]ywAl_V_TmympN^mA_LN^ NlTN_Jyi]A__V_TVm essential to mitigating the risk of catastrophic dam failures.
County of Los Angeles
All-Hazards Mitigation Plan
CoCCCouCouCouCCoCoCoCouCouCouCouCoCouCouuCCCCCCCCooouououCoCCCCCCCCCouCoCCCCouuuCCCoCCCoCouCoCouCoCoCoCCCCCC uouCoCCCC uouC uuuCCCCCCouCCCCououCCCCCCouCCoCououuCCoCoCCouCCCCCoCCCCoCoouuCCCCCoCCCoCoCoooCCooCoCCCCCoCCCoo nntyntyntyntyntyntyntyntyntyntytyntyntyntyntyntyntyntyntyntyntyntntyntyntyntytntyntntyntynttytyntyntyntyntyntntyyntyntyntynntytyntyntyntyntynnnnntyntynntyntyntynnntynntyntntynntyyntyyyntytyytttynnntytnntyt ofofofofoffofofoofofofofofofofofofofofofofofofofofoofoffofofofoffoofoffofofofoffffffoffffffffooffooffoooffff LoLLLLLoLoLoLLLoLoLoLoLooLoLoLoLLoLoLoLoLoLoLLoLoLLLLLLoLoLoLoooLLoLoLoLoLoLLoLoLLLLoLoLoLooLooLLoLLoLoLoLoLLoLoLoLLoLoLooLoLoLooLooLoLLoLoLoooLoooLoLoLoooooLoLoLoLoLooLoLoLoLoLoLLLoos AsAs As As AsAs As As AAAAs AAAs AAAAAAs As As AAs AAAs AAAAAAAAs As AsAsAs AAs AAsAAAs As AAAAAs AAAAAAAsAsAs As As AAAAAs Ass As As AAs As AsAAAs As As AAAs AAs AAAAss As AAs As AAss AsAsAAAs AAAAsAsAs AAsAsAAAAAssAsAAAAAsAs AAAAAAs AAAs As AAs AAs ss sss ngngengnngngngengngngengngengegegegegengegengengegegegeegeegengegegegeenggenggegegengengegengegengngengnnngeggggegengegeengeeeeengengennngnnggngeegegennngengengengggngngngngeengengngengggngeegeggeggggengengeegegenngnngengennngngengennngenggeggggenngenggeeennggggennnnngggennnngngggggegggggggg lesleslesleesleesleseseseseseseslesleslesleslelesleseslelleslesesleeslesesesslellelelllesleleleseleslesesessleleeeseeesseleeleeeesleleeeesesseseslleeeelleeeesllees AllAllAllAAllAllAllAllAllAAllAllAAAAllAllAllAllAllAAlAlAllAllAllAllAAlAllAAllAAAA lAA --------
HHHaHazHazazzHazHazHazzazHazaHHHHHaHazazHazzzHHHHHHHHHHHHazaazHHaazzzzHHHHazHazaazHazzzHHHHHHazzazHHHHHHazHazazazzHHHazzHHHHHHH zzHHHHaaaaazHHHHHaHHHHHHazzHHHaazHHHHHHHHHHHHaaaazHHHaazHHHHHaaaHHHHHHHazzHHHazHHazaa ardaardardrdardardardardardardaardarardaardarddrdarrddddda dddarararddddaaaaarardrdardardardrddardrdrrdrrrarrrra daa drr s Ms MsMsMsMs Ms s Ms MMMMMMMMMMMMMMs MMMMMMMMMMs Msss Ms MMMMMMMMMMMs MMMsMs sMsMMMMMMMMMMMs MMMsMssMMMMMMs MsMs MMMMMMs Mss MMMss sMMMMMMs MMMMMMMssss MMMMMMMMMsss MMMsss MMMMMMMMMMMMMMMMMMMMs MMMsMMMMMMs MMMMMMMMMMMMMMMMMM iitiitiitiitiitiitititiiiitittttitititiitiitiiiiiiititiititiitiiitititiitiiii iititiititiititiititititiittiittittitttit gatgagatgatgagagagagataatatgatgatgatatatgatatatatgagagagagagatatgatgagatatgatgatgagatgattgatgatgataaaagatgatgatgatgatggatgatagatgatgagagagatgatgatagatgatggggatgatatattatgg tgatggatatggagaggggatgatatttggaagagaaaaatggagagagaaggggggggggggggg oionnionionononononoioioononioniononioniononoononionionionionionionononnonionionioonionioonononionionononioononionionononnonioononononionoonionoonniioonooonononnnnnonnnonnnonionoonnonnnonnonioionoonnoooniononooo PlalaPlaPlaPlaPlaPlPlalPllPlaaPlaPlaPlaPlalPlaPlPlaPlaPlaPlaPlPlaPlalaPlPlaPllPlaPlaPlaPlPllaPlaPlaPlaPlaPlaPlaPlaPlaPlaaaPlaaPlaPlaPPlaPlaalaPlaaaPPlalaaaaPPlalPlaaaPPlaPlaaPP aaPlaPlaaaaaPlaPlaPlPlaPlaPlaPlaaPlaPPPlllaPlaaPPPPlPPPllaaaPPPPPP aPlaaaannnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn
6.8 Land Movement
6.8.1 Nature
Land movement refers to the downward
^avN^N_paSlaJ\maV]alLNIlVmA]a_TA
slope due to gravity. This process can occur
mqLLN_]yalTlALqA]]yavNlpV^NLNiN_LV_T
on contributing factors such as soil
Ja^iamVpVa_ m]aiN mpAIV]Vpy A_L NxpNl_A]
triggers. Land movement encompass a
variety of movement types including
^qLŔawm laJ\SA]]m LNIlVm Ŕawm ]A_L
m]q^im ]A_L mqImVLN_JN A_L maV]
^avN^N_p _ !am _TN]Nm aq_py pUN
diverse topography and geological
formations make certain areas more prone to
land ^avN^N_piAlpVJq]Al]yLqlV_TiNlVaLm
aSV_pN_mNilNJViVpApVa_mNVm^VJAJpVvVpyal
human land-qmN^aLVœJApVa_m
Climate change exacerbates land movement
by increasing the frequency and intensity of
NxplN^N wNApUNl NvN_pm mqJU Am UNAvy lAV_SA]] A_L ŔaaLV_T wUVJ U J A _ ] N A Lpa accelerated erosion and heightened landslide risks.
County of Los Angeles
All-Hazards Mitigation Plan
!A_L^avN^N_paSpN_aJJqlV_Ja_[q_JpVa_wVpUapUNl_ApqlA]UA| AlLmNxAJNlIApV_T their impact. Some of the primary contributing factors include:
x Seismic ActivityAlpUkqA\NmJA_LNmpAIV]V|Nm]aiNm]NALV_Tpa]A_L^avN^N_p A_LlaJ\SA]]m3UNSalJNaSmNVm^VJmUA\V_TJA_JAqmNmqLLN_SAV]qlNmiAlpVJq]Al]yV_ areas with pre-existing instability.
x NAvy0AV_SA]]A_L]aaLV_T : The likelihood of land movement increases after mqJJNmmVvNmpal^m-la]a_TNLalV_pN_mNlAV_SA]]mApqlApNmmaV]lNLqJV_TVpmJaUNmVa_ and triggering slope failures.
x Coastal Erosion:AvNmA_Lmpal^mqlTNNlaLNJaAmpA]J]VSSm]NALV_TpaV_mpAIV]Vpy A_LNvN_pqA]Ja]]AimNiAlpVJq]Al]yV_AlNAmmqJUAmaq_pyINA JUNmA_LJaAmpA] Ja^^q_VpVNm^A_yaSwUVJUUAvNilNvVaqm]yNxiNlVN_JNLmVT_VœJA_pNlamVa_ x :V]LœlNm!ammaSvNTNpApVa_LqNpaœlNmlNLqJNmpUNmaV]¯mAIV]VpypalNpAV_^aVmpqlN making slopes more susceptible to erosion and land movement during subsequent rain events.
x Burn Scars:V]LœlNIql_mJAlmmVT_VœJA_p]yN]NvApNpUNlVm\aS]A_L^avN ^N_pIy mplViiV_TpUN]A_LaSmpAIV]V|V_TvNTNpApVa_lNAmASSNJpNLIy^A[alœlNmmqJUAmpUN :aa]mNyVlN
aIJApVlN
lVLTNVlN Apa_VlN
A_L
Palisades Fire (2025) have shown increased susceptibility to land movement due to reduced soil stability and rapid runoff during rainstorms.
6.8.2 Location
Los Angeles County is home to multiple regions susceptible to land movement due to mpNNim]aiNmq_mpAI]NTNa]aTyA_LwNApUNliAppNl_m3UNA]VSal_VANa]aTVJA]1qlvNy (CGS) Landslide Susceptibility Map highlights high-risk areas. For a better visual replNmN_pApVa_aSpUN!A_L"avN^N_pA|AlLwVpUV_pUN!aq_pyi] A__V_TAlNA please reference Appendix A for maps that show areas that are susceptible to land movement and recent burn scars.
Potential land movement areas include (but are not limited to):
x Santa Monica Mountains
x San Gabriel Mountains
x Sierra Pelona Mountains
x Baldwin Hills
x Puente Hills
x Palos Verdes Hills
County of Los Angeles
All-Hazards Mitigation Plan
3UNmN AlNAm AlN iAlpVJq]Al]y vq]_NlAI]N LqN pa pUNVl mpNNi pNllAV_m wNA\ laJ\ Sal^ApVa_mA_LUVmpalyaSm]aiN^avN^N_pLLVpVa_A]]yUq^A_ AJpVvVpVNmmqJUAm TlALV_TNxJAvApVa_A_LJa_mplqJpVa_V_pUNmNlNTVa_mJA_Sqlp UNlLNmpAIV]V|NpUN Tlaq_LV_JlNAmV_TpUN]V\N]VUaaLaS]A_L^avN^N_plNAmV^iAJpNLIyiAmpwV]LœlNm \_aw_AmIql_mJAlmAlNA]maUVTU]ymqmJNipVI]Npa]A_L^avN^N _pAmpUN]ammaS vegetation reduces soil stability and increases erosion risks during heavy rains. This is particulal]yJa_JNl_V_TV_wV]LœlN-prone areas such as the Santa Monica Mountains and pUNSaapUV]]maSpUN1A_AIlVN]"aq_pAV_m wUNlNiamp -œlN]A_L^avN^N_pUAvN UVmpalVJA]]yJAqmNLmVT_VœJA_pLA^ATN
6.8.3 Extent
3UNNxpN_paS]A_L^avN^N_pV_!am_TN]NmVmmVT_VœJA_pA_LvAlVNLV_ŔqN_JNLIyVpm q_VkqNTNa]aTVJA]mNppV_TJJalLV_TpapUN1!A_Lm]VLN 1qmJNipVIV]Vpy"Ai approximately 750 square miles (15.75%) of Los Angeles County fall within high-risk landslide zones. The highest concentrations of deep-seated landslide susceptibility are distributed as follows:
Table 6-5 Landslide Susceptibility Map
Area High-0Vm\!A_Lm]VLN?a_Nm
mk^V]Nm
Percentage of Total Land
Area
Los Angeles County 750.02 15.75%
Unincorporated Areas 577.63 18.99%
Supervisorial District 1 17.29 7.02%
Supervisorial District 2 2.73 1.68%
Supervisorial District 3 114.61 26.58%
Supervisorial District 4 105.12 23.89%
Supervisorial District 5 509.31 18.14%
County of Los Angeles
All-Hazards Mitigation Plan
6.8.4 History
!A_L^avN^N_pUAvNUVmpalVJA]]yJAqmNLmVT_VœJA_pLA^ATNV_!am _TN]Nmaq_py aSpN_lNmq]pV_TV_ilaiNlpyLNmplqJpVa_V_SlAmplqJpqlNLA^ATNA_LlaALJ]amqlNmThere UAvNINN__aSNLNlA]LNJ]AlApVa_malmpApNilaJ]A^ApVa_mSalLA^SAV]qlNV_pUN]AmpœvN years. Some of the most notable events include:
x 1956 – Portuguese Bend Landslide : A massive landslide on the Palos Verdes Peninsula began in 1956 and remains active today. The movement of land has LVmi]AJNLUa^NmA_LV_SlAmplqJpqlNUVTU]VTUpV_TpUNlNTVa_¯ma _TaV_TTNa]aTVJ instability.
x 1994 – #alpUlVLTN AlpUkqA\N-Induced Land movement : The earthquake plVTTNlNL^alNpUA_^avV_TNvN_pmilV^AlV]yV_pUN1A_pA1qmA_A"aq_pAV_m A_L1A_AIlVN]"aq_pAV_mJAqmV_TNxpN_mVvNlaALA_LmplqJpqlA]LA^ATN x March 1995 – -AJVœJ-A]VmALNm!A_Lm]VLN : Heavy rains weakened the coastal I]qSSm]NALV_TpaA -foot-wVLNJa]]AimNpUApIqlVNLiAlpaSpUN-AJVœJaAmp Highway under 30 feet of debris.
x March 2005 – Sunset Mesa Landslide : A slope failure near Malibu caused over JqIVJyAlLmaSLNIlVmpaI]aJ\laALwAymA_LLA^ATNilaiNlpy x July 2023 – -NAlplNN!A_N!A_L"avN^N_p0a]]V_TV]]mmpApNm : A sudden m]aiNSAV]qlNlNmq]pNLV_pUNLVmi]AJN^N_paSUa^NmwUVJUwNlNlNL-tagged due to structural instability.
x September 2024 – JJN]NlApNL!A_L"avN^N_pV_0A_JUa-A]am9NlLNm : A mVT_VœJA_pV_JlNAmNV_]A_L^avN^N_pwVpUJNlpAV_AlNAmmUVSpV_TqipaSaqlV_JUNm iNlwNN\pawAlLpUNaJNA_pUlNApN_V_TlaALmA_LavNl lNmVLN_pVA]ilaiNlpVNm
6.8.5 Types of Land Movement
Debris Flow"qLŔaw1aV]"avN^N_p
NIlVmŔawV_va]vNmpUNlAiVL^avN^N_paSALN_mN^VxpqlNaSwA pNlmaV]laJ\A_L alTA_VJ ^ApNlVA] Law_ A m]aiN 3UVm ilaJNmm JA_ UAvN mVT_VœJA_pV ^ i A J p m a _ ]A_LmJAiNmNJamympN^mA_LUq^A_V_SlAmplqJpqlN
NIlVmŔawmAlNJUAlAJpNlV|NLIypUNVlŔqVL-like behavior and ability to transport large aI[NJpmmqJUAmIaq]LNlmA_LplNNm3UNyJA_plAvN]ApUVTUmiNNLm^A\V_TpUN^UVTU]y LNmplqJpVvN3UNJa^iamVpVa_aSALNIlVmŔawJA_vAlyIqpVppyiVJA]]yV_J]qdes:
County of Los Angeles
All-Hazards Mitigation Plan
x Water: A crucial component that facilitates movement. x 1aV]A_L0aJ\3UNmNilavVLNpUNIq]\aSpUN^ApNlVA]V_ALNIlVmŔaw x Organic Material: Includes vegetation and other natural debris that get caught in pUNŔaw
"qLŔawmAlNlAiVL movements of water-saturated earth materials that can cause mVT_VœJA_pLA^ATNpaIapU_ApqlA]N_vVla_^N_pmA_LUq^A_mNpp]N ^N_pm"qLŔawm AlNJUAlAJpNlV|NLIypUNVlŔqVL -]V\N^apVa_wUVJUaJJqlmwUN_maV]laJ\mA_LLNIlVm become saturated with water. 3UVmmApqlApVa_lNLqJNmpUNSlVJpVa_INpwNN_iAlpVJ]Nm A]]awV_TpUN^Ammpa^avNLaw_UV]]q_LNlpUNV_ŔqN_JNaSTlAvVpy NyJUAlAJpNlVmpVJm include:
x 1iNNLA_L9a]q^N"qLŔawmJA_plAvN]ApmiNNLmqipa ^V]NmiNlUaqlA_L
JA_JAlly]AlTNva]q^NmaS^ApNlVA]V_J]qLV_TlaJ\mplNNmA_LNvN_vNUVJ]Nm x Consistency: 3UNJa_mVmpN_JyaSA^qLŔawJA_vAlySla^ApUVJ\vVmJaqmm]qllypa AwApNlyŔaw3UVmLNiN_Lma_pUNilaialpVa_aSwApNlpama]VL^ApNlVA]m x Path: "qLŔawmpyiVJA]]ySa]]awNxVmpV_TLlAV_ATNiAppNl_mmqJUAml VvNlJUA__N]m A_LvA]]NymIqpJA_A]maJAlvN_NwiApUm]NALV_Tpaq_ilNLVJpAI]NA_LwVLNmilNAL damage.
1aV]^avN^N_pVmA_ApqlA]ilaJNmmpUApmVT_VœJA_p]yV^iAJpmpU NN_vVla_^N_pA_L human activities. It involves the displacement of soil particles due to various natural and human caused factors. Key characteristics include:
x Landslides: %SpN_ aJJqllV_T V_ UV]]y AlNAm ]A_Lm]VLNm V_va]vN pUN Law_wAlL movement of rock and soil. They can be sudden and fast- ^avV_T^A\V_TpUN^ particularly dangerous.
x Soil Creep: 3UVmVmAm]awA_LTlALqA]^avN^N_paSmaV]Law_Am]aiNaSpN_ q__apVJNLq_pV]mVT_VœJA_pLA^ATNaJJqlm
x 1aV]!VkqNSAJpVa_ qlV_TA_NAlpUkqA\NmApqlApNLmaV]JA_pN^ialAlV]y]amNVpm mplN_TpUA_LINUAvN]V\NA]VkqVLJAqmV_TmplqJpqlNmpamV_\alpV]p Causes
_ ! a m _ T N ] N m a q _ p y m N v N l A ] S A J p a l m J a _ p l V I q p N p a p U N a J J q l lN_JN aS LNIlVm Ŕawm^qLŔawmmaV]^avN^N_p
x NAvy0AV_SA]]A_L1pal^vN_pm_pN_mNA_Lila]a_TNLlAV_SA]]aSpN_AmmaJVApNL wVpUmpal^mJA_mApqlApNpUNmaV]lNLqJV_TVpmmpAIV]VpyA_LplVTTNlV_TLNIlVmŔawm County of Los Angeles
All-Hazards Mitigation Plan
3UNlNTVa_µm"NLVpNllA_NA_J]V^ApNwVpUwNpwV_pNlmA_LLlymq ^^NlmJlNApNm conditions conducive to such events.
x :V]LœlNm!am_TN]Nmaq_pySlNkqN_p]yNxiNlVN_JNmwV]LœlNmwUVJUJA_I ql_ and destabilize vegetation that normally helps hold soil in place. The loss of vNTNpApVa_V_JlNAmNmpUNlVm\aSmaV]NlamVa_A_LJa_mNkqN_p]yLNIlVmŔawmLqlV_T subsequent rainfalls.
x Steep Terrain: 3UNJaq_pyµm^aq_pAV_aqmpNllAV_V_J]qLV_T AlNAm]V\Naq_py ^aq_pAV_aqmAlNAmVmiAlpVJq]Al]yila_NpaLNIlVmŔaw3UNmpN Nim]aiNmSAJV]VpApN the rapid movement of debris downhill.
x Soil Composition: NlpAV_maV]pyiNmmqJUAmJ]Ay -lVJUmaV]mJA_INJa^NUVTU]y q_mpAI]NwUN_mApqlApNLwVpUwApNl^A\V_TpUN^^alNmqmJNipVI]NpaLNIlVmŔaw x Human Activity: 4lIA_LNvN]ai^N_plaALJa_mplqJpVa_A_LLNSalNmpApVa_JA_ A]pNl_ApqlA]]A_LmJAiNmA_LNxAJNlIApNJa_LVpVa_mpUAp]NALpaLNIlVmŔaw x Seismic Activity: !am_TN]Nmaq_pyVmmVpqApNLV_AUVTU]yAJpVvNmNVm^VJ|a_N ^A\V_TVpila_NpaNAlpUkqA\Nm1NVm^VJAJpVvVpyJA_]NALpama V]]VkqNSAJpVa_ ]A_Lm]VLNmA_LTlaq_LmUA\V_TA]]Ja_plVIqpV_TpamaV]LVmi]AJN^N_p !A_L1qImVLN_JN
Land subsidence is a gradual settling or sudden sinking of the Earth's surface due to various natural and human-V_LqJNLSAJpalm3UVmUA|AlLJA_UAvNmVT_VœJA_pV^iAJpma_ pUNN_vVla_^N_pV_SlAmplqJpqlNA_LJa^^q_VpVNm
lNLqJpVa_V_]A_LN]NvApVa_Vma_NaSpUN^amp_apVJNAI]NSNApqlNmaS]A_LmqImVLN_JN ]NALV_TpamVT_VœJA_pJUA_TNmV_pUN]A_LmJAiN3UVmiUN_a^N_a_ JA_aJJqlLqNpa _ApqlA]ilaJNmmNmmqJUAmpUNLVmma]qpVa_aS]V^Nmpa_NAmwN]]AmUq^A_AJpVvVpVNmlike pUN NxJNmmVvN NxplAJpVa_ aS Tlaq_LwApNl aV] al _ApqlA] TAm qlpUNl^alN ]A_L mqImVLN_JNV_JlNAmNmpUNlVm\aSŔaaLV_TINJAqmNpUN]awNlN]NvApVa_JA_]NALpaiaal LlAV_ATNA_LwApNlAJJq^q]ApVa_mpUNTlaq_LmV_\mVpaSpN_lNmq]pmV_pUNSal^Apion aSLNilNmmVa_mœmmqlNmA_LmV_\Ua]NmwUVJUJA_LlA^ApVJA]]yA]pNlpUNTNaTlAiUyA_L infrastructure of the area.
x Depressions: Are sunken or low-]yV_TAlNAma_pUNAlpU¯mmqlSAJNaSpN_Sal^NLIy natural or man-made processes.
x Fissures: lNA]a_T_AllawJlAJ\al]V_NAlaiN_V_TV_pUNAlpU¯mJlqmp x 1V_\Ua]NmAre holes in the ground causes by the collapse or sinking of surface material into an underlying void.
County of Los Angeles
All-Hazards Mitigation Plan
Causes
x laq_LwApNlxplAJpVa_ One of the primary causes of land subsidence in Los Angeles County is the excessive extraction of groundwater. As water is pumped out a S q _ L N l T l a q _ L A k q V S N l m p U N T l a q _ L A I a v N J A _ m V _ \ a l m N p p ] N ]NALV_T pa subsidence.
x %V]A_LAmxplAJpVa_The removal of oil and natural gas from beneath the earth's surface also contributes to land subsidence. This extraction can create voids and lNLqJNilNmmqlNV_mqIpNllA_NA_]AyNlmJAqmV_TpUNTlaq_LpamV_\ x Natural Soil Compaction: %vNlpV^N_ApqlA]ilaJNmmNmmqJUAmmaV]Ja^iAJpVa_ can lead to gradual subsidence. In areas with loose or q_Ja_ma]VLApNLmaV]mpUN wNVTUpaSavNl]yV_T^ApNlVA]mJa^iAJpmpUNTlaq_LlNmq]pV_TV_ A]awNlV_TaSpUN land surface.
Rock Falls
Rock falls are a natural geological phenomenon where rock fragments break free from a steep slope or cliff and tumble downward. These events can range from small iNII]NmLVm]aLTV_Tpa^AmmVvNIaq]LNlmJlAmUV_TLaw_wVpUmVT_V œJA_pSalJNA_L impact.
Rock falls are characterized by:
x Speed and Suddenness: 0aJ\SA]]maJJqlkqVJ\]yA_LwVpUaqp^qJUwAl_V_T making them particularly dangerous.
x 9AlVNL1V|NmThe size of the falling material can range from small pebbles to large Iaq]LNlmV^iAJpV_TpUNmNvNlVpyaSpUNNvN_p
x Path Predictability: :UV]NpUNV_VpVA]plVTTNliaV_pVmaSpN_VLN_pVœAI]NpUNiApU aS descent can be unpredictable due to varying terrain and obstacles.
Causes
The primary causes of rock falls include:
x Weathering and Erosion: %vNlpV^NwNApUNlV_TilaJNmmNmmqJUAmSlNN|N -thaw JyJ]NmJUN^VJA]wNApUNlV_TA_LpUNAJpVa_aSwApNlJA_wNA\N_ laJ\mplqJpqlNm lamVa_JA_q_LNl^V_NpUNIAmNaSm]aiNm^A\V_TlaJ\m^alNmqmJNipVI]NpaSA]]V_T x Seismic Activity: Los Angeles County is located in a seismically active region. AlpUkqA\NmJA_LVm]aLTNlaJ\mSla^J]VSSmA_LmpNNim]aiNmplVTTNlV_TlaJ\SA]]m County of Los Angeles
All-Hazards Mitigation Plan
x NAvy0AV_SA]]_pN_mNalila]a_TNLlAV_SA]]JA_mApqlApNpUNTlaq_LV_JlNAmV _T the weight and pressure on rock faces. This saturation can lead to the loosening and collapse of rocks.
x Human Activity: a_mplqJpVa_^V_V_TA_LapUNlUq^A_AJpVvVpVNmJA_LNmpAIV]V|N rock formations. The vibrations from heavy machinery and blasting can initiate rock falls.
6.8.6 Probability
!A_Lm]VLNmA_LapUNl]A_L^avN^N_pNvN_pmUAiiN_V_!am_TN]Nmaq_pySAVl]yaSpN_ NmiNJVA]]yASpNlUNAvylAV_alV_AlNAmpUAplNJN_p]yUALwV]LœlNmalAlNila_Npam]VLV_T x 1^A]]]A_Lm]VLNm]V\NLNIlVmŔawm AlN^amp]V\N]yLqlV_TyNAl mwVpUUNAvylAV_ NmiNJVA]]y]#V`ayNAlm3UNmNUAiiN_NvNlypayNAlmpUNl NVmÈpa È
chance each year during those cycles.
x In high-lVm\|a_Nm]V\NmpNNi^aq_pAV_m]aiNmwVpUAUVmpalyaS^avN^N _p probability is 1–ÈJUA_JNiNlyNAlNmiNJVA]]ySa]]awV_T^q]pV-year wet periods al^A[alwV]LœlNm
x Some areas of the County have been experiencing continuous sliding.
6.8.7 Vulnerability
!A_L^avN^N_piamNlVm\mpa]VSNilaiNlpyA_LNmmN_pVA]V_SlA mplqJpqlN3UN THIRA projects that approximately 1.2 million residents in Los Angeles County could be directly or indirectly affected by land movement. The most at-risk populations include:
x 0NmVLN_pmaSUV]]mVLNA_LJA_ya_Ja^^q_VpVNmmqJUAm"A]VIq3a iA_TAA_LpUN Palos Verdes Peninsula.
x Homeowners in coastal bluff areas that are facing erosion-driven slope failures. x a^^q_VpVNmV_wV]LœlNIql_mJAlAlNAmwUNlNpUN]ammaSvNTNp ApVa_V_JlNAmNm landslide probability during heavy rains.
x The Access and Functional Needs (AFN) community who may face challenges in evacuating or leaving landslide-prone areas.
County of Los Angeles
All-Hazards Mitigation Plan
Contextual Overview
Los Angeles County’s diverse topography includes many hillside communities susceptible to deep-mNApNL]A_Lm]VLNmNmiNJVA]]yASpNlwV]LœlNalUNAvylAV_3UNm N hazards can isolate Ja^^q_VpVNmLA^ATNilaiNlpyA_LLVmlqip]VSN]V_Nm Extent of Exposure
x Total Area Exposed: 284.57 sq mi
x Supervisorial Districts (SD) Impacted:
o SD5: 151.96 sq mi (5.41%)
o SD3: 90.23 sq mi (20.93%)
o SD4: 25.94 sq mi (12.20%)
o SD1: 13.77 sq mi (3.90%)
o SD2: 2.68 sq mi (0.74%)
x Critical Facilities Affected:
o Fire Department: 41 (12.17%)
o Public Works: 32 (13.91%)
o Health Services: 12 (18.46%)
o Public Health: 4 (10.00%)
o Libraries: 9 (10.34%)
o Parks: 27 (14.92%)
o Education: 8 (9.76%)
Problem Statement
!A_Lm]VLNmiamNAmNlVaqmlVm\paUV]]mVLNJa^^q_VpVNmA_LAJJNmmlaqpNmNmiNJVA]]yV_ AlNAmlNJavNlV_TSla^wV]LœlNqllN_pLNvN]ai^N_pA_LlaALV_SlAmplqJpqlN^Ay_ap be resilient against slope failure. Mitigation actions should include slope stabilizApVa_ pAlTNpNLIqyaqpmallN]aJApVa_mA_LNAl]ywAl_V_TmympN^m
County of Los Angeles
All-Hazards Mitigation Plan
6.8.8 Impacts
Los Angeles County's diverse landscape and dense population make it highly mqmJNipVI]NpapUNNSSNJpmaS]A_L^avN^N_pASSNJpV_TJlVpVJA]V_SlAmplqJpqlNA_LlAVmV_T mVT_VœJA_pNJa_a^VJmaJVA]A_LmASNpyJa_JNl_m
3lA_mialpApVa_#Npwal\m
!am_TN]Nmaq_pyµmNxpN_mVvNplA_mialpApVa__Npwal\VmvVpA] SalLAV]yJa^^qpNm TaaLmplA_mialpA_LN^NlTN_JymNlvVJNm!A_L^avN^N_pJA_mNvNlN]yV^iAJppUNmN systems:
x 0aALA^ATNAqmNmJ]amqlNm hazardous driving conditions and costly repairs AmmNN_A__qA]]ya_-AJVœJaAmpVTUwAy- A_L^A_yapUNl]aJA]laALm x Bridge Compromise SSNJpm mplqJpqlA] V_pNTlVpy _NJNmmVpApV_T J]amqlNm A_L expensive reconstructions.
x Public Transit Disruptions^iAJpmplAV_plAJ\mA_LIqmlaqpNm]NALV_TpaLN]Aym and service interruptions.
x 0AV]1ympN^m 3lAJ\^VmA]VT_^N_pJA_JAqmNLN]AymA_LiapN_pVA]LNlAV]^N_pm affecting both passenger and freight lines.
Water Supply Systems
The county's water delivery system is complex and vulnerable to land movement:
x Compromised Pipelines !NALm pa lqipqlNm al ]NA\m LVmlqipV_T mqii]y A_L requiring major repairs.
x 0NmNlvaVl^iAJp: Landslides can affect water quality and storage capacity.
Energy Infrastructure
!A_L^avN^N_piamNmlVm\mpa!am_TN]Nmaq_pyµmN_NlTyV_SlAmplqJpqlNV_J]qLV_T x ]NJplVJA]lVL9q]_NlAIV]VpVNm Land movement can damage power lines and mqImpApVa_mJAqmV_TaqpATNm
x Am-ViN]V_N0Vm\m1aV]mUVSpmJA_lNmq]pV_TAm]NA\malNxi]amVa_mN_LA_TNlV_T safety.
County of Los Angeles
All-Hazards Mitigation Plan
Communication Systems
0N]VAI]NJa^^q_VJApVa_VmJlVpVJA]A_L]A_L^avN^N_pJA_LVmlqip x Telecommunication Towers: Structural damage can impair cellular and internet services.
x Underground Cables: AlpUmUVSpmJA_LA^ATNJAI]NmASSNJpV_TJa__NJpVvVpy Emergency Services Facilities
x Hospitals and Fire Stations: mmN_pVA]SalN^NlTN_JylNmia_mNIqpmplqJpqlA] LA^ATNJaq]LV^iNLNaiNlApVa_mq_LNlmJalV_TpUN_NNLSallNmV]VN_pJa_mplqJpVa_ and strategic planning.
Economic Impacts
x Infrastructure Damage: !NALmpaJamp]ylNiAVlmA_L^AV_pN_A_JNaSlaALmIlVLTNm and buildings.
x Property Loss: a^Naw_NlmSAJNœ_A_JVA]]ammNmLqNpailaiNlpyLA^ATNal devaluation.
Environmental Impacts
x Ecosystem Disruption: Soil movement can lead to habitat loss A_LASSNJp]aJA]ŔalA and fauna.
x Increased Pollution: lamVa_JA_lNmq]pV_mNLV^N_plq_aSSLNTlALV_TwApNlkqA]Vpy in rivers and oceans.
For a better visual representation of the Land Movement Hazard within the LA County i]A__V_T AlNA i]NAmN lNSNlN_JNiiN_LVx for maps that show areas that are susceptible to land movement and recent burn scars.
6.8.9 Mitigation Strategies
3alNLqJNpUNV^iAJpaS]A_L^avN^N_p!am_TN]Nmaq_pyUAmV^i]N^N_pNLmNvNlA] ^VpVTApVa_A_LilNiAlNL_NmmmplApNTVNmV_J]qLV_T
x !A_L4mNA_LNvN]ai^N_p0NTq]ApVa_m Restricting development in high-risk landslide zones to prevent new structures from being built on unstable terrain. x _SlAmplqJpqlN 0NmV]VN_JN Reinforcing existing infrastructure through slope mpAIV]V|ApVa_ila[NJpmlNpAV_V_TwA]]mA_LV^ilavNLLlAV_ATNmympN^m County of Los Angeles
All-Hazards Mitigation Plan
x 1pAIV]V|ApVa_ 0NTq]ApVa_m Implementing stricter grading and excavation regulations to minimize the destabilization of slopes.
x Public Awareness Campaigns: _UA_JV_T ]A_Lm]VLN NAl]y _apVœJApVa_m Iy monitoring potential movement areas and precipitation thresholds. x Evacuation Planning: Developing evacuation plans for at- lVm\ Ja^^q_VpVNm ensuring residents receive timely alerts and clear guidance. x Public Education: Conducting public education campaigns to inform residents about recognizing landslide warning signs and preparedness measures. x Operational Area Coordination_JlNAmV_TJaalLV_ApVa_AJlammmpApNSNLNlA]A_L %SœJNaS^NlTN_Jy"A_ATN^N_paSœJVA]mwVpU]aJA][qlVmLVJpVa_m paV^ilavN forecasting and response efforts.
6.8.10 Summary
!A_L^avN^N_plN^AV_mAmVT_VœJA_pUA|AlLV_!am_TN]Nmaq_py iAlpVJq]Al]yV_ mpNNiA_LJaAmpA]lNTVa_m3UN-A]am9NlLNm-N_V_mq]A1A_pA"a_VJA"aq_pAV_mA_L 1A_AIlVN]"aq_pAV_mAlNA^a_TpUN^ampvq]_NlAI]NAlNAmwith climate change and human activities exacerbating risks. By implementing land- qmN lNTq]ApVa_m V_SlAmplqJpqlNlNV_SalJN^N_pmA_LN^NlTN_JylNmia_mNV^ilavN^N_pmpUNaq_pyJA_ enhance resilience and reduce losses in the future. Local governments and communities must actively monitor and manage contributing factors to effectively mitigate the impacts of land subsidence.
County of Los Angeles
All-Hazards Mitigation Plan
6.9 Tsunami
6.9.1 Nature
This section characterizes tsunamis as
high-N_NlTy]a_T -wavelength ocean
waves generated primarily by
mVT_VœJA_p aSSmUalN mNVm^VJ NvN_pm
(such as subduction zone
NAlpUkqA\Nm mqI^AlV_N ]A_Lm]VLNm
or volcanic eruptions. In the context of
!am _TN]Nm aq_py pmq_A^Vm
represent a relatively infrequent but
potentially high-impact hazard that
could produce rapid coastal
inundation and surge impacts.
Characteristics:
x 3lVTTNlNL^AV_]yIyLVmpA_p]AlTN-
magnitude seismic events.
x Features long wavelengths and prolonged arrival times. x AiAI]NaSilaLqJV_TlAiVLLNNiV_q_LApVa_A]a_T]aw-lying coastal areas. x _mq^^Alypmq_A^VmAlNLy_A^VJ_ApqlA]iUN_a^N_AwVpUpUNiapN_pVA]paJAqmN mqLLN_JaAmpA]ŔaaLV_TA_LLA^ATNVSAplVTTNlV_TNvN_paJJqlm County of Los Angeles
All
--
HazH ards Mitigation
Plan
County of Los Angeles
All-Hazards Mitigation Plan
6.9.2 Location
3UNqiLApNLpmq_A^VUA|AlLilaœ]NSaJqmNma_pUNJaAmpA] areas of Los Angeles County. The new zone map—developed using enhanced modeling techniques and updated coastal geomorphology data—UVTU]VTUpmAlNAmA]a_TpUN-AJVœJmUalN]V_NpUAp AlNAplVm\3UNmNV_J]qLNlNTVa_mAL[AJN_ppapUN!am_TN]Nm AmV_iAlpmaS!a ng
NAJU1A_pA"a_VJA
AyA_LapUNl]aw-elevation coastal zones.
For a better visual representation of Tsunami Inundation zones within the LA County i]A__V_TAlNAi]NAmNlNSNlN_JNiiN_LVxAf o r A¬3mq_A^V_q_LApVa_lNA map.
Important Details:
x Coastal segments from the western margins of the Los Angeles Basin extending to the border with Orange County.
%vNlA]]pUN coastal areas aS!am_TN]Nmaq_py containing our communities and infrastructureface heightened exposure.
6.9.3 Extent
4mV_T pUN ]ApNmp UyLlaLy_A^VJ A_L V_q_LApVa_ ^aLN]V_T pUN qiLApNL pmq_A^V inundation (zone)^AiilavVLNmAlNœ_NLvVNwaSpUNNxpN_paSiapN_pVA]ŔaaLV_T3UN ^ A i V ] ] q m p l A p N m U a w p m q _ A ^ V w A v N m J a q ] L i l a i A T A p N V _ ] A _ L m U a w V_T lNvVmNL boundaries that account for current sea-level conditions and future sea-level rise projections.
Highlights:
x _q_LApVa_LNipUmA_LlNAJUUAvNINN_lNJA]Jq]ApNLwVpUma^NA lNAmiapN_pVA]]y experiencing water levels up to several feet in depth.
x 3UNV_]A_LlNAJUaSŔaaLV_TvAlVNmIy]aJA]paiaTlAiUywVpUŔA p]aw-lying areas showing the greatest potential for impacts ^iAJpNLAlNAmV_J]qLNIqpAlN_ap ]V^VpNLpa!a_T
NAJU3UNialpmaS!a_T
NAJUA_L!am_TN]Nm"AlV_ALN]0Ny
Venice and Santa Monica.
x lVpVJA]V_SlAmplqJpqlNwVpUV_pUNqiLApNL|a_NmUAmINN_VLN_p VœNLpailValVpV|N mitigation and evacuation routes for planning.
_NmmN_JNpUNNxpN_paSpmq_A^VV^iAJpmVm_aw^AiiNL^alNilNJVmN]yaSSNlV_T]aJA] decision-^A\NlmAJ]NAlNlvVNwaSiapN_pVA]ŔaaLV_TLNipUmA_LLVmpA_JNmV_]A_L.
County of Los Angeles
All-Hazards Mitigation Plan
6.9.4 History
VmpalVJA]]ymVT_VœJA_ppmq_A^VNvN_pmV_pUN!am_TN]NmlNTV a_AlNlAlNpUaqTU distant seismic events (for example: the 1960 Chilean tsunamialpUN^amplNJN_p Tonga tsunami) have been known to produce measurable impacts. Historical records combined with geological studies indicate that while tsunamis have occurred in the iAmppUNVlSlNkqN_JyVm]awJa^iAlNLpaapUNlUA|AlLmawNvNlpUNlNTVa_¯milaxV^Vpy to major tectonic boundaries necessitates ongoing vigilance.
Historical Context:
x Past events have been sporadic but can serve as valuable lessons for preparedness. x VmpalVJA]V_q_LApVa_lNJalLmA_LmNLV^N_pmpqLVNmJa_œl^pUAp pmq_A^VmUAvN reached the Los Angeles coast in prehistory.
x Lessons learned from past minor events underscore the importance of maintaining updated hazard maps.
3UqmwUV]NUVmpalVJA]pmq_A^VNvN_pmAlNV_SlNkqN_ppUNyilavVLNAJlVpVJA]Ja_pNxpSal understanding future risks and guiding preparedness measures. There have been no SNLNlA]LNJ]AlApVa_malmpApNilaJ]A^ApVa_mSalpmq_A^VV_pUN]AmpœvNyNAlm
6.9.5 Probability
The probability of a tsunami affecting Los Angeles County is generally low when Ja^iAlNLpa^alNSlNkqN_pUA|AlLm]V\NNAlpUkqA\NmalŔaaLm#N vNlpUN]NmmpUN potential for a distance source pmq_A^VTN_NlApNLIyALVmpA_p large seismic event remains a realistic risk. Updated probabilistic assessments—incorporating recent seismic data and tsunami modeling V_LVJApNpUApwUV]NpUNavNlA]]]V\N]VUaaLVm]awpUN consequences in the event of a tsunami can be severe.
Probability Considerations:
x Low annual probability but high consequence if an event occurs !am_TN]Nm County has about a 2% annual chance.
x Distance source events from subduction zones across the ocean contribute most to the risk.
x Continuous monitoring and updated modeling are essential to reassess the risk over time.
x _mq^^AlypUNilaIAIV]VpyaSApmq_A^VlN^AV_m]awIqpLqNp apUNiapN_pVA]Sal high-V^iAJpaqpJa^NmVpwAllA_pmJa_pV_qaqmmpqLyA_LilNiAlNL_Nmm County of Los Angeles
All-Hazards Mitigation Plan
6.9.6 Vulnerability
aAmpA]vq]_NlAIV]VpyV_!am_TN]Nmaq_pyVmmVT_VœJA_p]yV_Ŕ qN_JNLIySAJpalmmqJU Am qlIA_ LN_mVpy ]aw-N]NvApVa_ pNllAV_ ATV_T V_SlAmplqJpqlN A_L maJVa-economic conditions. The updated tsunami zone map now better delineates areas where these vulnelAIV]VpVNmAlN^ampila_aq_JNLUVTU]VTUpV_TJa^^q_VpVNmpUAp^AyUAvN]V^VpNL evacuation routes and fewer resources to recover from rapid inundation. Iaqp
iNai]N]VvNV_iAlpmaS!am_TN]Nmaq_pypUApJaq]LINŔaaLNL IyApmq_A^V"A_y people a]mawal\V_pUNmNJaAmpA]AlNAmA_LAlaq_Lq_UaqmNLV_LVvV LqA]m]VvN pUNlN^A\V_TpUN^NmiNJVA]]yAplVm\INJAqmNpUNy^Ay_apUAvNNAmyAJJNmmpamUN]pNl or transportation.
3aqlVm^ALLmNvN_^alNiNai]NpapUNmNAlNAmNmiNJVA]]yLqlV_T IqmywNN\N_Lmal Ua]VLAym-]AJNm]V\N1A_pA"a_VJAJA_mNNqipavVmVpa lmALAyLqlV_TiNA\ times. This makes evacuating harder if a tsunami warning is issued. Roads near the coast ca_kqVJ\]yINJa^NJlawLNLA_LvVmVpalm^Ay_ap\_awpUNINmpwA ypa]NAvN 3lASœJJaq]Lm]awLaw_N^NlTN_Jyi]A_mmaVp¯mV^ialpA_ppaUA vNJ]NAlmVT_mNAl]y wAl_V_TmA_LTaaLplASœJJa_pla]paUN]iiNai]NTNppamASNpykqVJ\]y Factors:
x High population density in low-lying coastal areas.
x lVpVJA]V_SlAmplqJpqlNNTUamiVpA]mqpV]VpVNm ialpmA_LmUViiV_T transportation networks) located within the inundation zones.
x Socio-economic and language barriers that may hinder effective emergency response.
x Limited natural barriers in some coastal segments.
x Vulnerable communities include those with high population densities and critical infrastructure near the coast.
4]pV^ApN]ypUNvq]_NlAIV]VpyaSpUNlNTVa_VmJa^iaq_LNLIyIa pUiUymVJA]NxiamqlNm A_LmaJVA]SAJpalmq_LNlmJalV_TpUN_NNLSalpAlTNpNL^VpVTApVa_NSSalpm Contextual Overview
aAmpA]Ja^^q_VpVNmV_!am_TN]Nmaq_pyV_J]qLV_TialpmA_L paqlVmp|a_NmAlNAp risk from tsunamis. These rare but highly destructive events can inundate coastal infrastructure with little warning.
County of Los Angeles
All-Hazards Mitigation Plan
Extent of Exposure
x Total Area Exposed: 32.89 sq mi
x Supervisorial Districts (SD) Impacted:
o SD4: 15.83 sq mi (7.43%)
o SD3: 12.59 sq mi (2.92%)
o SD2: 2.03 sq mi (0.56%)
x Critical Facilities Affected:
o Fire Department: 16 (4.75%)
o Public Works: 9 (3.91%)
o Health Services: 3 (4.62%)
o Public Health: 1 (2.50%)
o Libraries: 5 (5.75%)
o Parks: 13 (7.26%)
o Education: 3 (3.66%)
Problem Statement
3mq_A^VmJA_JAqmNlAiVLA_LJApAmplaiUVJJaAmpA]ŔaaLV_T:VpU JlVpVJA]JaAmpA] V_SlAmplqJpqlNA_LlNmVLN_pVA]AlNAmNxiamNLNmiNJVA]]yV_1A_L1pUNlNVmA_NNL SallaIqmpNvAJqApVa_i]A__V_TvNlpVJA]NvAJqApVa_mUN]pNlmA_LJa^^q_VpyaqplNAJU to enhance preparedness and reduce vulnerability.
6.9.7 Impacts
1Uaq]LApmq_A^VaJJqlpUNiapN_pVA]V^iAJpma_!am_TN]Nma q_pyJaq]LIN extensive. Parts of Los Angeles County that could be impacted by a Tsunami are Marina N]0Ny-alpaS!am_TN]Nm-alpaS!a_T
NAJUA_LapUNlbeach communities in low
lying areas. 3UNqiLApNLV^iAJpAmmNmm^N_pmlNŔNJpiammVI]NmJN_AlVamlA_TV_ TSla^ mVT_VœJA_pilaiNlpyLA^ATNpa]ammaS]VSNA_L]a_T-term economic disruption. The new zone map aids in quantifying these impacts by providing detailed inundation depths and spatia]NxpN_pmpUNlNIyA]]awV_TSalINppNllVm\Ja^^q_VJApVa_A_Li]A__V_T
County of Los Angeles
All-Hazards Mitigation Plan
Potential Impacts:
x 1NvNlNŔaaLV_TaSJaAmpA]V_SlAmplqJpqlNA_LlNmVLN_pVA]AlNAm x VmlqipVa_aSplA_mialpApVa_qpV]VpymNlvVJNmA_LN^NlTN_JylNmia_mNaiNlApVa_m x Ja_a^VJ]ammNmV_\NymNJpalmmqJUAmpaqlVm^mUViiV_TA_L]aJA]Ja^^NlJN x 1aJVA] V^iAJpm V_J]qLV_T LVmi]AJN^N_p ]amm aS ]VvN]VUaaLm A_L JUA]]N_TNm V_ emergency sheltering.
_mUalppUNiapN_pVA]V^iAJpmaSApmq_A^VAlNSAl -lNAJUV_T_NJNmmVpApV_TlaIqmp ^VpVTApVa_NvAJqApVa_A_LlNJavNlyi]A__V_Tpa^V_V^V|NUAl^ For a better visual representation of Tsunami Inundation zones within the LA County i]A__V_TAlNAi]NAmNlNSNlN_JNiiN_LVx for A¬3mq_A^V_q_LApVa_lNA^Ai.
6.9.8 Summary
The updated tsunami section for the 2025 AHMP V_JalialApNmpUN]ApNmpmJVN_pVœJ œ_LV_TmA_L^AiiV_TpNJU_VkqNmpailavVLNA^alNilNJVmNq_LNlmpA_LV_TaSpmq_A^V lVm\mV_!am_TN]Nmaq_py
yV_pNTlApV_TA_qiLApNLV_q_LApV a_|a_N^AipUN
lNvVmVa_ J]AlVœNm pUN miApVA] NxpN_p aS iapN_pVA] ŔaaLVng and highlights the vulnerabilities in coastal communities. This comprehensive update is designed to guide decision-^A\NlmV_N_UA_JV_TilNiAlNL_NmmpAlTNpV_T^VpVTApVa_mplApNTVNmA_L strengthening community resilience.
Ny3A\NAwAym
x Nature: Tsunamis are infrequent but high-energy events capable of rapid coastal inundation.
x Location & Extent: 3UNqiLApNL|a_N^AiVLN_pVœNmvq]_NlAI]NJaAmpA]AlNAmwVpU lNvVmNLV_]A_LŔaaLNxpN_pm
x History & Probability: VmpalVJA]NvN_pmAlNlAlNUawNvNldistance events remain a realistic risk.
x 9q]_NlAIV]VpyË^iAJpm High population density and critical infrastructure in JaAmpA]|a_NmA^i]VSylVm\wVpUiapN_pVA]SalmNvNlNNJa_a^VJA_LmaJVA]LVmlqipVa_ 3UVmqiLApNLmNJpVa_VmV_pN_LNLpamNlvNAmAJlVpVJA]paa]Salia]VJy^A\NlmN^NlTN_Jy ^A_ATNlmA_LJa^^q_VpympA\NUa]LNlmAmpUNywal\paTNpUNlpalNLqJNpUN]a_T-term risks associated with tsunamis and enhance overall regional resilience.
County of Los Angeles
All-Hazards Mitigation Plan
CouCoCoCoCCCooCCCCoCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC ntytyyyyyyyyyyyyyy ofofooofofofofofffofofffofofffofofoooooofofofoooooffoooooooo LoLoLoLoooLoLoLooLoLooLoLLoLoLLoooLoLoLoLoLLLooLoLLLoooooLoLoooooLLLooLoooooosAsAAsAs AsAsAAsssAAAAAAAsssAsssAsAssAsAAAAAAAAssssssAsAsAsAAAssAs AsAAs Angengengngenngngengngenngenngnnngengengengngngngngenngngengngnnngngngngnngngnnnggggggggggggggggggg leslesesesessesssesessssesssessseseseessesesssesessseeeesseseseeesseeeesesessssssssss AAAAllAAAAAAAAAAAAA
-
Hazards MMMMMMMMMMMMMMMMMMMMMMitiititiitiittitiitiitiiiititiitititittitiiitiitititittittititiititittittttittttitiitititttitttiittttiiiititiiiiittititiittittiitiitiitittiiitiititttiiiiititiiitttiitiittttttittttttiitt ggatgatggggggggg ionoonnononioniononionionioionononionoonononononooonooonooooooonnnnnnnnnnnnnnn Plaaannnnn
6.10 Severe Wind and Tornado
6.10.1 Nature
Severe wind and tornadoes pose
m V T _ V œ J A _ p p U l N A p m p a ] V S N i l a i N l p y A _ L V_SlAmplqJpqlN pUaqTU pUNy LVSSNl V_
frequency and intensity within Los Angeles
aq_py 1NvNlN wV_L NvN_pm iAlpVJq]Al]y
1A_pA_AwV_LmAlNAlNJqllV_T_ApqlA]
hazard that can cause widespread
LA^ATNV_J]qLV_TLaw_NLiawNl]V_Nm
plNN SA]]m A_L mplqJpqlA]damage. These
winds originate from high-pressure
mympN^mavNlpUNlNAp
AmV_Sq__N]V_TLly
and warm air through mountain passes into
the coastal and valley regions at high
speNLmLLVpVa_A]]ympal^ -LlVvN_wV_Lm
^VJlaIqlmpm straight-line winds and gust
fronts associated with severe weather can
JlNApNUA|AlLaqmJa_LVpVa_maSpN_]NALV_T
paplA_mialpApVa_LVmlqipVa_mœlNUA|AlLm
and prolonged power outages.
County of Los Angeles
All-Hazards Mitigation Plan
3al_ALaNmwUV]NlN]ApVvN]ylAlNV_pUNlNTVa_UAvNINN_lNJal LNLA_LJA_JAqmN localized but intense damage. These vi olent windstorms form when unstable Ap^amiUNlVJJa_LVpVa_milaLqJNlapApV_TqiLlASpmlNmq]pV_TV_ ASq__N]J]aqLpUAp contacts the ground.
6.10.2 Location
Severe wind events affect the entire Los Angeles County planning area wVpUpUN mpla_TNmpaJJqllN_JNmV_JA_ya_iAmmNmvA]]NymA_LJaAmpA]lN TVa_m The Santa Ana wV_LmAlN^ampV_pN_mNV_pUNSA]]A_LwV_pNl^a_pUmiAlpVJq]Al]yV^iAJpV_TAlNAmin the 9A]]NyA_L foothill communities of the County. Storm-LlVvN_wV_Lma_pUNapUNlUA_L can impact any part of the county and vary in intensity based on weather patterns. 3UNmN wV_Lm JA_ lNAJU miNNLm aS pa ^iU ma^NpV^Nm NxJNNLV_T pUamN pUlNmUa]Lm]NALV_TpamVT_VœJA_pLA^ATN
Tornadoes are more sporadic in occurrence and can develop in various parts of the Jaq_pyiAlpVJq]Al]yV_]aw]A_LAlNAmwUNlNmNvNlNpUq_LNlmpal^mUAvNpUNiapN_pVA]pa form rotating systems.
6.10.3 Extent
Winds and breezes are common occurrences in LA County. As wind speeds increase so does the potential for a catastrophic event. Hot dry winds can reach high speeds as pUNyLNmJN_LSla^pUNV_]A_LLNmNlplNTVa_mJlNApV_T_apa_]yJlVpVJA]wV_LNvN_pmIqp almaNxplN^N]yLA_TNlaqmœlNJa_LVpVa_mA_LJa_plVIqpV_TpapUNm ilNALaSwV]LœlNm 3UNwV_LmAlNJ]AmmVœNLV_pUN
NAqSalp:V_L1JA]NmNNFigure 6.10.1 below. Beaufort
wind scale is an empirical scale that rela tes wind speed to observed conditions at sea or land. It uses numerical scale from 1-12 to describe wind force based on visual observations of the effects of the wind and gives quantitative measures of the wind. For NxA^i]NaVmLNmJlVINLAm®JA]^¯AmNA]V\NA^VllalwUV]N LNmJlVINLAmUqllVJA ne force with devastating conditions.
3al_ALaNmAlNJ]AmmVœNLqmV_TpUN_UA_JNLq[VpA Scale Figure 6.10.2. The _UA_JNLq[VpA 1JA]NVmmiNJVœJA]]yqmNLpalApNpUNV_pN _mVpyaSpal_ALamIAmNL a_pUNLA^ATNpUNyJAqmNLA^ATNV_LVJApalm mqJUAmIqV]LV_Tp yiNmA_LplNNmp ranges from EF-0 to EF-
wVpUV_JlNAmV_T_q^INlmV_LVJApNmpla_TNlpal_ALamA_ d more severe damage. While tornadoes in the region typically do not exceed EF-1 County of Los Angeles
All-Hazards Mitigation Plan
V_pN_mVpypUNyJA_mpV]]ilaLqJNLA^ATV_TwV_LmAIavN^iU JAiAI]NaSpNAlV_T laaSmaSSIqV]LV_TmqilaapV_TplNNmA_LavNlpql_V_TvNUVJ]Nm Beaufort Wind Scale:
Force
Wind
(Knots)
WMO
Classification
Appearance of Wind Effects
On the Water On Land
0 Less
than 1 Calm Sea surface smooth and
mirror-like
A]^m^a\NlVmNm
vertically
1 1-3 Light Air 1JA]ylVii]Nm_aSaA^JlNmpm
Smoke drift indicates
wV_LLVlNJpVa_mpV]]wV_L
vanes
2 4-6 Light Breeze 1^A]]wAvN]NpmJlNmpmT]Ammy
no breaking
:V_LSN]pa_SAJN]NAvNm
lqmp]NvA_NmINTV_pa
move
3 7-10 Gentle
Breeze
!AlTNwAvN]NpmJlNmpmINTV_
paIlNA\mJAppNlNLwUVpNJAim
Leaves and small twigs
Ja_mpA_p]y^avV_T]VTUp
flags extended
4 11-16 Moderate
Breeze
Small waves 1-4 ft. becoming
]a_TNl_q^NlaqmwUVpNJAim
qmp]NAvNmA_L]aamN
iAiNl]VSpNLm^A]]plNN
branches move
5 17-21 Fresh Breeze
Moderate waves 4-8 ft taking
]a_TNlSal^^A_ywUVpNJAim
some spray
Small trees in leaf begin
to sway
6 22-27 Strong
Breeze
Larger waves 8-Sp
wUVpNJAimJa^^a_^alN
spray
Larger tree branches
^avV_Twhistling in
wires
7 28-33 Near Gale
1NAUNAimqiwAvNm-Sp
white foam streaks off
breakers
:Ua]NplNNm^avV_T
resistance felt walking
against wind
County of Los Angeles
All-Hazards Mitigation Plan
8 34-40 Gale
Moderately high (18-25 ft)
wAvNmaSTlNApNl]N_TpU
edges of crests begin to
IlNA\V_pamiV_LlVSpSaA^
blown in streaks
3wVTmIlNA\V_TaSSplNNm
generally impedes
progress
9 41-47 Strong Gale
High waves (23-Sp mNA
INTV_mpala]]LN_mNmplNA\m
aSSaA^milAy^AylNLqJN
visibility
Slight structural damage
aJJqlmm]ApNblows off
roofs
10 48-55 Storm
Very high waves (29-41 ft)
wVpUavNlUA_TV_TJlNmpmmNA
white with densely blown
SaA^UNAvyla]]V_T]awNlNL
visibilit
y
Seldom experienced on
]A_LplNNmIla\N_al
qilaapNL´Ja_mVLNlAI]N
mplqJpqlA]LA^ATN´
11 56-63 Violent Storm
Exceptionally high (37-52 ft)
wAvNmSaA^iApJUNmJavNl
mNAvVmVIV]Vpy^alNlNLqJNL
12 64+ Hurricane
VlSV]]NLwVpUSaA^wAvNm
avNl
SpmNAJa^i]NpN]y
wUVpNwVpULlVvV_TmilAy
visibility greatly reduced
Figure 6.10.1 ĞĂƵĨŽƌƚtŝŶĚ^ĐĂůĞ
County of Los Angeles
All-Hazards Mitigation Plan
Enhanced Fujita Scale:
THE ENHANCED FUJITA SCALE (EF SCALE)
03# 1NJa_Lqmp"- "
EF 0 65-85 MPH !VTUp
lA_JUNmIla\N_
minor roof damage
EF 1 86-110 MPH Moderate: Roofs
LA^ATNLplNNmqilaapNL
EF 2 111-135 MPH Considerable: Roofs torn
aSS]AlTNplNNmLaw_
EF 3 136-165 MPH 1NvNlNa^NmLNmplayNL
cars lifted
EF 4 166-200 MPH Devastating: Houses
]NvN]NLLNIlVmAVlIal_N
EF 5 Over 200 MPH Incredible: Homes swept
away total destruction
6.10.4 History
Los Angeles County has experienced multiple severe wind events and occasional tornadoes in recent history wUVJUJAqmNLLNmplqJpVa_mA_LwV]LœlNm. There have been no federal declarations or state proclamations for Severe Wind & Tornadoes in the last œvNyNAlm Some notable incidents include:
x November-December 2011: wV_LNvN_pJAqmNL^alNpUA_¸ ^V]]Va_V_
damages and severely impacted several foothill communities and unincorporated areas.
x December 2019: An EF-pal_ALapaqJUNLLaw_V_1aqpU!am_TN]NmJAqmV_T minor roof damage and downing power lines.
x January 2021: mNvNlNwV_Lmpal^V^iAJpNLpUNlNTVa_]NALV_TpaLA^ATN across multiple communities and emergency response efforts to clear roadways. x September 2021: An EF-0 tornado developed near the community Lake of Los _TN]NmÈ_aLA^ATNwAmlNialpNL
Figure 6.10.2 Enhanced Fujita Scale
County of Los Angeles
All-Hazards Mitigation Plan
x April 2023: An EF-0 tornado recorded in Cerritos causing tree damage. x March 2023 (0 ): An EF- pal_ALamplqJ\"a_pNIN]]aa_NaSpUN mpla_TNmp pal_ALaNm lNJalLNL V_ pUN AlNA JAqmV_T mVT_VœJA_p LA^ATN pa commercial structures and vehicles.
x May 2023: An EF-0 tornado occurred near the communities of Carson and Compton damaging buildings and vehicles.
x August 2023 ( 0
): Tropical Storm Hillary impacting Los Angeles
County.
x February 2024: Strong winds impacting across Eastern Santa Monica Mountain and Santa Clarita Valley.
x March 2024: Strong winds impacting areas around San Gabriel Valley. x January 2025 (0
): A mNvNlNwV_Lmpal^V^iAJpNLpUNlNTVa_]NALV_T
to a -apN_pVA]]yA_TNlaqm1VpqApVa_-1 lNLŔATJa_LVpVa_m1Nv NlA]œlNm Ila\NaqpV_pUNAlNAwUVJUNxUVIVpNLNxplN^NœlNINUAvValJAqmV_TwVLNmilNAL destruction.
x March 2025 (0
): miAlpaSAmpal^NvN_pA_ EF-0 tornado struck Pico 0VvNlAA]VSal_VAAp
A^with wind speeds reaching up to 85 mph.
6.10.5 Probability
1NvNlNwV_LNvN_pmAlNAlNTq]AlaJJqllN_JNV_!am_TN]Nmaq_ pywVpUAU igh probabilityÈJUA_JN recurring annually. Santa Ana winds are particularly common LqlV_TpUNJaa]Nl^a_pUmA_LJ]V^ApNiAppNl_mmqTTNmppUApNxplN^NwV_LNvN_pm^Ay become more frequent due to changing weather dynamics. Because wind events and pal_ALamAlN]aJA]V|NLV__ApqlNilaIAIV]VpyvAlySla^a_NAlN ApaA_apUNlA_LVm LVSœJq]ppaLNpNl^V_NiNlJN_pATNaSUAiiN_V_TV_a_NAlNA Tornadoes remain a low- probability hazard10% chance in the planning areaUawNvNlTVvN_iAmpaJJqllN_JNm they cannot be ruled out entirely. Atmospheric conditions capable of producing pal_ALaNm^AyAlVmNLqlV_TmNvNlNpUq_LNlmpal^miAlpVJq]Al]yV_wV_pNlmpal^mympN^m that generate strong wind shear. While the likelihood of an EF-2 or stronger tornado is ^V_V^A]pUNiapN_pVA]Sal]aJA]V|NLLA^ATNlN^AV_m The Santa Ana winds occur ten to twenty-œvNpV^NmA__qA]]yA_LJA_]AmpSalmNvNlA]LAymiamV_TAlNJq llV_TpUlNApaS damage and disruption in Los Angeles County.
County of Los Angeles
All-Hazards Mitigation Plan
6.10.6 Vulnerability
SNvNlNwV_LA_Lpal_ALaNmJA_INNxpN_mVvNASSNJpV_TIapUV_SlAmplqJpqlNA_LiqI]VJ safety. High-wV_LNvN_pmiamNAlVm\paJlVpVJA]V_SlAmplqJpqlNiAlpVJq]Al] yiawNl]V_Nm Ja^^q_VJApVa_ mympN^m A_L plA_mialpApVa_ _Npwal\m qV]LV_TmNmiNJVA]]y a]LNl
structures and ^aIV]NUa^NmAlNvq]_NlAI]NpawV_L -lN]ApNLLA^ATNV_J]qLV_TlaaS SAV]qlNmwV_LawIlNA\ATNA_LmplqJpqlA]Ja]]AimN
_ALLVpVa_paiUymVJA]LA^ATNmNvNlNwV_LNvN_pmJA_JAqmNmV T_VœJA_pNJa_a^VJ LVmlqipVa_m-la]a_TNLiawNlaqpATNmV^iAJpIqmV_NmmNmUNA]pUJ AlNSAJV]VpVNmA_L emergency response services. Road closures and debris blockages hinder mobility and commercNwUV]NwV_L -LlVvN_wV]LœlNmAmNJa_LAlyUA|AlLaS1A_pA_AwV_LmJA_ lead to devastating losses.
-qI]VJmASNpyVmA]maA^A[alJa_JNl_wVpUlVm\maSŔyV_TLNIl VmvNUVJ]NAJJVLN_pm avNlpql_NLvNUVJ]Nm and respiratory issues caused by airborne dust and pollutants stirred up by high winds.
Severe wind and tornado events disproportionately impact certain populations and infrastructure in Los Angeles County due to both geographic exposure and maJVaNJa_a^VJvq]_NlAIV]VpVNm3UNmNUA|AlLmJA_LVmlqipJlVpVJ A]mNlvVJNmNxAJNlIApN existing inequa]VpVNmA_LmVT_VœJA_p]yLA^ATNmplqJpqlNm_apIqV]ppawVpUmpA_LNxplN^N wind conditions.
9q]_NlAI]N-aiq]ApVa_m
%qpaSpUNJaq_py¯mNmpV^ApNL^V]]Va_lNmVLN_pmpUNSa]]a wV_Tiaiq]ApVa_mAlN considered especially vulnerable:
x Older Adults (65+): Approx. 1.6 million residents (15.5%)—more likely to suffer injury or health complications during wind-related power outages and evacuation events.
x Access and Functional Needs (AFN) Populations: Estimated 1.7 million V_LVvVLqA]m È V_J]qLV_T pUamN wVpU LVmAIV]VpVNm ]V^VpNL ^aIV]Vpy al communication barriers.
x Low-Income Households: Over 13% of households fall below the poverty line and may lack the resources for structural mitigation or relocation during prolonged outages.
County of Los Angeles
All-Hazards Mitigation Plan
x -Nai]N xiNlVN_JV_T a^N]Nmm_Nmm - %vNl
V_LVvVLqA]m
!1Jaq_p ApLVlNJplVm\Sla^SA]]V_TLNIlVmA_L]AJ\aSmU N]pNlLqlV_T windstorms.
x "aIV]Na^N0NmVLN_pmiilaxV^ApN]yq_VpmJaq_pywVLNJa_JN_plApNL in inland valleys and foothill communities that are highly exposed to Santa Ana winds.
x UV]LlN_4_LNlTN
laq_LJaq_pywVLNvq]_NlAI]Npa lNmiVlApaly complications from airborne particulates and debris stirred by strong winds. x Ja_a^VJ^iAJp
qmV_NmmLVmlqipVa_mV_JlNAmNLV_mqlA_JNJ]AV ^mA_LpUN JampmaSN^NlTN_JylNmia_mNA_LlNJavNlyALLœ_A_JVA]IqlLN_mp a]aJA] communities.
lVpVJA]_SlAmplqJpqlNAp0Vm\
Severe wind and tornado events can cause widespread cascading failures in vital mympN^mV_J]qLV_T
x -awNl _SlAmplqJpqlN !am _TN]Nm aq_py Ja_pAV_m avNl ^V]Nm aS overhead power lines vulnerable to high-wV_LLA^ATNA_LœlNVT_VpVa_ x "NLVJA]AJV]VpVNm%vNl
]VJN_mNLUamiVpA]mA_LUNA]pUJ]V_ VJm^A_ylN]VA_p on uninterrupted power and access for vulnerable patient populations. x Transportation Corridors: Major highways (I-
-41 - A_LavNl
IlVLTNmiAlpVJq]Al]yV_JA_ya_A_LSaapUV]]AlNAmAlNmqmJNipVI]NpaaImplqJpVa_ by fallen trees and debris.
x Communication Towers: Over 800 critical telecom sites serve the county’s emergency communications and can be disrupted by high wind gusts. x 1JUaa]miilaxV^ApN]yiqI]VJ –12 schools and 100+ college campuses face operational disruptions from power outages or infrastructure damage during events.
6.10.7 Impacts
1NvNlNwV_LA_Lpal_ALaNvN_pmiamNmVT_VœJA_ppUlNApmpaJlVpVJA]V_SlAmplqJpqlNiqI]VJ mASNpyA_LJa^^q_VpyaiNlApVa_mV_!am_TN]Nmaq_pyVTUwV _LmmqJUAmpUamN LqlV_T1A_pA_ANvN_pmlNTq]Al]yLA^ATNiawNl]V_Nmqilaapp lNNmA_LLVmAI]N County of Los Angeles
All-Hazards Mitigation Plan
plA_mialpApVa_ JallVLalm _apAI]N NxA^i]N aJJqllNL V_ A_qAly wUN_
wVLNmilNALwV_Lmpal^mJAqmNLiawNlaqpATNmSal^alNpUA_ Jqmpa^Nlm V_J]qLV_T AiilaxV^ApN]y !am _TN]Nm NiAlp^N_p aS :ApNlA _ L - a w N l !:- Jqmpa^NlmA_LavNl
00 Southern California Edison (SCE) customers.
qlV_TpUVmmA^NiNlVaLwV]LœlNmNxAJNlIApNLIypUNmpla_TwV_ LmV^iAJpNLmNvNlA] ^NLVJA]SAJV]VpVNmLVmlqipV_TJlVpVJA]UNA]pUmNlvVJNmA_LlNk qVlV_TpUNN^NlTN_Jy relocation of patients.
3al_ALaNmwUV]NlAlNUAvNA]maLN^a_mplApNLLNmplqJpVvNJAiAJVpyV_]aJA]V|NLAlNAm _"AlJU
A_-pal_ALapaqJUNLLaw_V_-VJa0VvNlALaw_V_TiawNl]V_NmA_L plNNmA_LaImplqJpV_TlaALwAymUVTU]VTUpV_TpUNiapN_pVA]Sal pal_ALVJAJpVvVpypa impact urban communities. These hazards not only endanger life and property but also pUlNApN_NJa_a^VJJa_pV_qVpyA_LpUNSq_JpVa_V_TaSN^NlTN_Jym NlvVJNmiAlpVJq]Al]y in vulnerable neighborhoods and areas with aging infrastructure.
6.10.8 Mitigation and Preparedness
Efforts to mitigate the effects of severe wind and tornadoes should focus on improving mplqJpqlA] lNmV]VN_JN N_UA_JV_T NAl]y wAl_V_Ts and alerts A_L V_JlNAmV_T iqI]VJ awareness of such events.
Severe Wind and Tornado Mitigation
x Strengthening building codes to require wind-resistant design features.
Promoting the use of wind-resistant ma terials and construction techniques in new developments.
x Conducting regular tree-trimming and vegetation management to reduce infrastructure damage risks.
x 0NplaœppV_TA_LlNV_SalJV_TJlVpVJA]V_SlAmplqJpqlNmqJUAmiawNl]V_NmA_LqpV]Vpy mympN^mpawVpUmpA_LUVTU-wind conditions.
x Implementing public education campaigns on windstorm preparedness and safety measures.
x Leveraging early warning alerting and ilNiAlNL_Nmm^NmmATV_TAmwN]]Am integrating emergency messaging with local broadcast and mobile networks.
County of Los Angeles
All-Hazards Mitigation Plan
6.10.9 Summary
1NvNlNwV_LA_Lpal_ALaNmpUaqTULVSSNlV_TV_SlNkqN_JylN^AV_iapN_pVA]UA|AlLmSal Los Angeles County. Santa Ana winds and storm-driven gusts regularly impact the lNTVa_JAqmV_TLA^ATNpaV_SlAmplqJpqlNA_LV_JlNAmV_TwV]LœlNlVm\m:UV]Npal_ALaNm alNlAlNpUNVlaJJAmVa_A]aJJqllN_JN_NJNmmVpApNmilNiAlNL_NmmA_L^VpVTApVa_NSSalpm
y V^i]N^N_pV_T mpla_TNl IqV]LV_T JaLNm lNV_SalJV_T JlVpVJA] V_SlAmplqJpqlN A_L enhancing preparedness and iqI]VJAwAlN_NmmpUNJaq_pyJA_lNLqJNVpmvq]_NlAIV]Vpy to these hazards helps to better protect its residents from potential hazards of severe winds and tornado and improve community resilience.
County of Los Angeles
All-Hazards Mitigation Plan
CouCouCouCouCouCountyntyntyntyntyntyyyyyyy ofofofofofofof LoLoLoLoLoLos As AsAsAs AsAAAngengengengeggngegegengengengegegeggegeggeeeeeegegeeegeegegegeeeeeeeeeeegggggeeeeeeeegegggggggeeeeeeegggggggeeegeegegggggggggeeeeeeggggggggeeeeeggggggeggggggelesleslesleseseleleelesslesleseseseseeeelelesleslesleeeeslesllleseseleslesllleeeeesleseeleslesleesellleeeeseseseeeesleseeelesseeeesseeeesssseseeesesslesllllleell sllle AAllAAllAllAllAllAAAA
---
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6.11 Mass Violence
6.11.1 Nature
3 U V m m N J p V a _ a q p ] V _ N m p U N L N œ _ V _ T JUAlAJpNlVmpVJm aS ^Amm vVa]N_JN
wUVJU V_J]qLNm V_pN_pVa_A] UVTU-
V^iAJpV_JVLN_pmmqJUAmpNllalVm^
A J p V v N m U a a p N l N v N _ p m v N U V J ] N- l A ^ ^ V _ T m A _ L a p U N l J a a l L V _ A p N L attacks. Understanding the nature of
these events is critical for
developing effective mitigation
strategies.
x Mass violence includes both
pAlTNpNL AppAJ\m NT
ideologically motivated
terrorism) and opportunistic
AJpmNTAJpVvNmUaapNlmal
violent assaults in public
spaces).
x 3UNmNV_JVLN_pmAlNJUAlAJpNlV|NLIypUNVl]awwAl_V_TpV^NUV TU]NpUA]VpyA_L potential to incite widespread fear and panic.
County of Los Angeles
All-Hazards Mitigation Plan
x Acts of mass violence
may be perpetrated by
V_LVvVLqA]mm^A]]Tlaqim
or well-organized
_Npwal\m A_L JA_
V_va]vN œlNAl^m
Nxi]amVvNm vNUVJ]Nm al
biological agents.
x These attacks often aim
to disrupt societal
Sq_JpVa_m LA^ATN
V_SlAmplqJpqlN al Nxi]aVp
vulnerabilities in soft
pAlTNpmmqJUAmmJUaa]m
i ] A J N m a S w a l m U V i a l
entertainment venues.
_mq^^AlypUN_ApqlNaS^Amm
violence lies in its deliberate
V_pN_ppaV_ŔVJpUAl^a_Tlaqim
A_L LVmlqip iqI]VJ alLNl
making strong mitigation
measures essential for
protecting life and property of
Los Angeles County.
6.11.2 Extent
The potential extent of mass
violence is characterized by its
ability to cause widespread
LVmlqipVa_A_LmVT_VœJA_p]ammaS
life and property.
County of Los Angeles
All-Hazards Mitigation Plan
x Events can result in many casualties and severe physical and psychological impacts.
x Mass violence can LVmlqip NmmN_pVA] mNlvVJNm mplAV_ N^NlTN_Jy lNmia_mN mympN^mA_LJlNApNJAmJALV_TmaJVaNJa_a^VJNSSNJpm
x 3UNavNlA]]LVmlqipVa_^AyNxpN_LSAlINya_LpUNV^^NLVApNmJN_ NASSNJpV_T broader community resilience.
_ NmmN_JN wUV]N pUNmN NvN_pm ^Ay IN lAlN pUNVl NxpN_mVvN V^iAJpm _NJNmmVpApN comprehensive planning and resilient infrastructure.
6.11.3 History
VmpalVJA]LApAV]]qmplApNmpUAp^AmmvVa]N_JNUAmNva]vNLavNlpV^NwVpUNAl]VNlNvN_pm shaping current mitigation strategies and more recent incidents underscoring emerging vulnerabilities. Previous mitigation and other plans referenced events such as large-scale terrorist attacks and active shooter incidents. x 0NJN_pNvN_pmV_pUN]AmpœvNyNAlmV_J]qLNUVTU -ilaœ]NAJpVvNmUaapNlV_JVLN_pm ApmJUaa]miqI]VJplA_mialpApVa_UqImA_LJa^^NlJVA]JN_pNlm AmwN]]Am vehicle-ramming attacks in urban areas.
%vNlA]]pUNUVmpalVJA]plN_LmUawmpUApwUV]NSlNkqN_JylN^AV_ m]awpUNmNvNlVpyaS mass violence i_JVLN_pmUAmNmJA]ApNL_NJNmmVpApV_TJa_pV_qA]qiLApNmpa^VpV TApVa_ strategies.
6.11.4 Location
"AmmvVa]N_JNV_JVLN_pmpN_LpaaJJqlV_AlNAmwUNlNiNai]N_Ap qlA]]yJa_TlNTApN V_J]qLV_TqlIA_JN_pNlmplA_mialpApVa_UqImNLqJApVa_A] and religious V_mpVpqpVa_m mUaiiV_TJN_pNlmA_LiqI]VJevents and venues.
x -qI]VJmiAJNmmqJUAmplA_mVpmpApVa_mmpALVq^m^A]]m and other locations where ]AlTN_q^INlaSiNai]NAmmN^I]N are considered higher-risk areas. x Critical infrastructure location like government buildings and commercial centerare often targeted.
x Certain events may also occur in areas lacking adequate physical security or surveillance.
County of Los Angeles
All-Hazards Mitigation Plan
3UqmVLN_pVSyV_TA_LmNJqlV_TUVTU -density locations is a key focus for mitigating the effects of mass violence.
6.11.5 Probability
3UNilaIAIV]VpyaS^AmmvVa]N_JNV_JVLN_pmVmLVSœJq]ppailNLVJpilNJVmN]yUawNvNlpUN potential for occurrence is recognized as a persistent low- SlNkqN_JyUVTU-impact risk that requires constant vigilance.
x Such incidents are statistically rare yet present a disproportionate risk due to their catastrophic consequences.
x Threat assessments and intelligence reports indicate that evolving tactics may increase probability over time.
x a_pV_qaqm^a_VpalV_TA_LqiLApNLpUlNApA_A]ymNmNTvVA30ilaJNmmNm are essential in quantifying risk levels.
_ mq^^Aly wUV]N ^Amm vVa]N_JN NvN_pm AlN _ap Ja^^a_ pUNVl V_UNlN_p unpredictability and high severity demand that communities prepare as if an incident could occur at any time.
6.11.6 Vulnerability
Mass vVa]N_JNLNiN_Lma_AvAlVNpyaSSAJpalmV_J]qLV_TiUymVJA]V_SlAmplqJpqlNLNmVT_ iqI]VJAwAlN_NmmmNJqlVpyilNiAlNL_NmmA_LV_pNlATN_JyJaalLV_ApVa_ x Critical vulnerabilities include open public spaces with minimal physical barriers or limited or ineffective safety / security protocols in place. x ௗAimV_plAV_V_TA_LilNiAlNL_NmmA^a_TœlmplNmia_LNlmJA_NxAJNlIApNpUN situation during an active incident.
x Social vulnerabilities—such as communication gaps or lack of multilingual emergency information—may hinder rapid response and community resilience. 3Uqm lNLqJV_T vq]_NlAIV]Vpy V_va]vNm V_vNmpV_T V_ V_SlAmplqJpqlN UAlLN_V_T laIqmp mNJqlVpy^NAmqlNmlNTq]AlplAV_V_TNxNlJVmNmA_LNSSNJpVvNiq I]VJJa^^q_VJApVa_ strategies.
County of Los Angeles
All-Hazards Mitigation Plan
6.11.7 Impacts
3UNV^iAJpmaS^AmmvVa]N_JNNvN_pmAlN^q]pVSAJNpNL life safetyJa^^q_VpympAIV]Vpy and the local economy.
x ^^NLVApN V^iAJpm V_J]qLN SApA]VpVNm V_[qlVNm A_L plAq^A A^a_T ASSNJpNL populations.
x 1NJa_LAlyV^iAJpm^AyN_Ja^iAmmila]a_TNLLVmlqipVa_aS]aJA]m NlvVJNm NJa_a^VJLaw_pql_mA_L]AmpV_TimyJUa]aTVJA]NSSNJpma_Ja^^q_VpVNm x Long-term consequences can involve extensive resource allocation for recovery A_L^VpVTApVa_SqlpUNlmplAV_V_TiqI]VJmympN^m
"AmmvVa]N_JNV_ŔVJpmV^^NLVApNUAl^A_LaSpN_plVTTNlmAJUAV_aSmNJa_LAlyV^iAJpm that complicate community recovery and strain long-term resilience efforts.
6.11.8 Summary
_Ja_J]qmVa_^VpVTApV_TpUNUA|AlLmaS^AmmvVa]N_JNlNkqVlNm A_V_pNTlApNL^q]pV - ]AyNlNL AiilaAJU pUAp miA_m ilNvN_pVa_ ilNiAlNL_Nmmresponse and recovery.
Communities must implement measures to secure high- lVm\ ]aJApVa_m qiTlALN iUymVJA]A_LLVTVpA]mNJqlVpyN_UA_JNV_pNlATN_JyJaalLV_ApVa_ A_LJa_pV_qaqm]y update training and threat assessments.
x "VpVTApVa_mplApNTVNmV_J]qLNiUymVJA]mNJqlVpyN_UA_JN^N_pmNTIAllVNlmA_L mqlvNV]]A_JN lNTq]AlAJpVvNmUaapNlLlV]]mV^ilavNLN^NlTN_JyJa^^q_VJApVa_ mympN^mA_LJaalLV_ApNL]AwN_SalJN^N_pA_LiqI]VJUNA]pUlNmia_mNm x Investment in resilience-building measures and community outreach helps to N_mqlNpUApV_pUNNvN_paSA_V_JVLN_pJa^^q_VpVNmJA_lNJav NlkqVJ\]yA_L effectively.
This section underscores that while mass violence NvN_pmAlNlAlNpUNVliapN_pVA]Sal high impact demands rigorous preparedness and adaptive mitigation strategies to safeguard lives and maintain community functionality.
County of Los Angeles
All-Hazards Mitigation Plan
6.12 Cybersecurity Incidents
6.12.1 Nature
Cybersecurity incidents refer to
disruptive events affecting digital
networks and systems. These events
involve the unauthorized electronic
or physical access of information
systems that jeopardizes or disrupts
pUN V_pNTlVpy Ja_œLN_pVA]Vpy al
availability of information. Cyber
incidents can range from minor
targeted data breaches to large -
scale ransomware attacks and
distributed denial-of-service (DDoS)
events that compromise critical
infrastructure. Common types of
JyINlmNJqlVpyV_JVLN_pmV_J]qLNIqp
are not limited to:
x Data Breaches: 3UNJa^ila^VmNq_AqpUalV|NLLVmJ]amqlNalq_AqpUalV|NL acquisition of information.
CouCo ntytyttyyntyy offofofo LoLoLoLLLoLLLLLooLLLosAs AsAs As AsAsAs AsAs As As As As AA AAs AAAAAAAAAAAAAngengengngengengengengengengngegngengengengengengngegegeenggngegengeegngenng lesleslesesleslesllesleslesleslesleseslesleesesleslesessesleseslleselel AllAA
-
HazHazHazHHHHHazHazHazzzHaa ardardardrdardardrddardddddardddardddrdds Ms Ms Ms Ms Ms MsMsMMs Ms MsMMsMMMMs MMMMMs MMMs Ms MMs Ms MMs Mitiitiitiitiitititiitiitiitiiititiititiitttitiiitititt gatgatgatgagatgatgatgatgatgatgatgatgatatgatgatgatggagatgagatagggggattaaaa ioiononionionionionionnnionionionionionnnnononionnoonnonnonnoionoonnoonoononionnononniooonnnnooooonooononnnnnn PlPlPlPlPlPlPlPllPPPllPPlPlPPPPPlPllPlaPlaPPPPPlPlaPPPPlPlPPPPPPPlaaPPPPllPlPlaPPPllaPPP nn
County of Los Angeles
All-Hazards Mitigation Plan
x Malware: "A]VJVaqm UAlLwAlN œl^wAlN al maSpwAlN pUAp Vm V_pN_pVa_A]]y included or inserted in a system for a harmful purpose. x 0A_ma^wAlN A type of malicious software designed to lock access to a system until a ransom payment is received. Note that ransom payment is not a guarantee that system access will be restored by the threat actor. x Denial of Service (DoS): _AppAJ\^NA_ppamUqpLaw_A^AJUV_Nal_Npwal\ rendering it inaccessible to its intended users.
x Distributed Denial of Service (DDos): A DoS attack that uses numerous hosts to perform the attack.
x Insider Threats: :UN_A_V_mVLNlNTA_N^i]ayNNalvN_Lal qmNmpUNVl AqpUalV|NLAJJNmmwVppV_T]yalq_wVppV_T]ypaLaUAl^paA_alTA_V|ApVa_ x -UVmUV_TppAJ\m The fraudulent practice of sending emails purporting to be from reputable senders in order to induce individuals to reveal information or download malware by clicking on a link.
Key characteristics of a cybersecurity incident include:
0AiVL%_mNp Impacts to operations can occur suddenly and evolve quickly. x Sophistication: Can be highly sophisticated with state or non-state actors involved.
x yIlVLppAJ\m May involve both cyber and physical components due to interdependencies.
x Non-Malicious Incidents: Technological failures that cause similar impacts to cybersecurity incidents may also occur due to non-malicious reasons such as a software or hardware issue.
Understanding the inherent digital nature and complex characteristics of these incidents is critical to developing effective prevention and mitigation strategies.
6.12.2 Location
4_]V\NplALVpVa_A]UA|AlLmpUApUAvNAiUymVJA]TNaTlAiUVJSaap ilV_pJyINlmNJqlVpy V_JVLN_pmAlNV_UNlN_p]yplA_mIaq_LAlyawNvNlpUNVlNSSNJpm^A_VSNmp]aJA]]ypUlaqTU the disruption of critical services and syst ems and necessitate regionally coordinated preparedness and response efforts.
County of Los Angeles
All-Hazards Mitigation Plan
qlVmLVJpVa_A]0N]NvA_JN
x Impact local government networks and county infrastructure. x Affect public and private sector systems within Los Angeles County. x Disrupt critical infrastructure such as utilities and cause cascading impacts. x _va]vNJyINl_aLNmpUApwUV]NT]aIA]]yLVmplVIqpNLJa_vNlTN a_lNTVa_A] networks.
Critical Sectors Impacted:
x Hospitals and healthcare facilities.
x FinancialIA_\V_TaliAyla]]systems.
x Transportation providers and systems.
x 4pV]VpVNmmqJUAmN]NJplVJVpyTAmA_LwApNl
x Emergency response and public safety agencies.
6.12.3 Extent
The extent of cybersecurity incidents is measured not only by the volume of Ja^ila^VmNLLApAalœ_A_JVA]]ammIqpA]maIypUNiapN_pVA]LVm lqipVa_paNmmN_pVA] services and critical infrastructure.
Scope of Impacts:
x Rapid spread across interconnected digital systems.
x Potential for cascading failures that disrupt multiple sectors. x Economic losses that may run into millions of dollars.
Measurable Factors:
x Number of systems compromised.
x Downtime of critical infrastructure and services.
x Financial costs from remediation and lost productivity.
The extensive reach of cybersecurity incidents—both in terms of economic impact and service disruption—highlights the need for robust digital defenses Ja_pV_qVpy aS aiNlApVa_mi]A__V_TIAJ\qimympN^mA_LlNLq_LA_JVNmLVmAmpNl lNJavNlymplApNTVNm and regional cyber response coordination.
County of Los Angeles
All-Hazards Mitigation Plan
6.12.4 History
VmpalVJA]]y JyINlmNJqlVpy V_JVLN_pm UAvN Nva]vNL Sla^ Vma]ApNL IlNAJUNm pa coordinated attacks that leverage global networks. Early cybersecurity incidents focused on data theft and vandalism. More recent attacks have grown increasingly sophisticated and targeted critical infrastructure or use complex ransomware. Cyber threat actors include state-sponsored groups along with non-state groups such as criminal enterprises and terrorist organizations. Recent years have seen cybersecurity incidents affecting ]AlTNJalialApVa_miqI]VJN_pVpVNmV_J]qLV_T]aJA]TavNl_^N_pmA_L critical infrastructure sectors. Previous major cybersecurity incidents have included:
x !am_TN]Nmaq_py1qiNlValaqlp0A_ma^wAlNppAJ\ Resulted in pUNmUqpLaw_aS_NAl]yNvNlyJaqlpmympN^A^q]pV-LAyJ]amqlNaSpUNJaqlpA_L cascading impacts to operations.
x amiVpA]laqippAJ\A major hospital company experienced an attack that caused IT and phone system outages and disrupted patient care at several Los Angeles County hospitals.
x 3N]NJa^^q_VJApVa_ _Lqmply ppAJ\m: A series of attacks against telecommunications providers in the United States resulted in compromised customer data.
x VpyppAJ\A cybersecurity incident at a city within Los Angeles County JAqmNLJVpy3mympN^mpaINpA\N_aSŔV_N
x vVApVa__LqmplyppAJ\m A series of cybersecurity incidents targeting the airports and airlines caused transportation system disruptions.
The historical progression from rudimentary attacks to highly coordinated cybersecurity incidents underscores the growing importance of proactive risk management in the digital realm.
6.12.5 Probability
The probability of cybersecurity incidents occurring is increasing as digital interconnectivity expands and as attackers continue to innovate their methods.
County of Los Angeles
All-Hazards Mitigation Plan
0Vm\Trends:
x Rapid expansion of the Internet of Things (IoT) pUN _Npwal\ aS V_pNl_Np- connected devices ranging from smart refrigerators to autonomous vNUVJ]Nm has added new attack vectors to the threat landscape.
x Increasing sophistication of cybercriminal methods including zero-LAyNxi]aVpm a previously unknown cybersecurity vulnerability.
x Growing frequency of reported incidents nationally and globally.
Contributing Factors:
x Inadequate cybersecurity measures in legacy systems still being used by organizations.
x Underinvestment in cyber defense infrastructure or cybersecurity expertise. x Greater digital reliance in everyday operations without proper continuity of operations planning.
VvN_JqllN_pplN_LmA_LpNJU_a]aTVJA]LNvN]ai^N_pmpUN]V\N]VUaaLaSJyINlmNJqlVpy V_JVLN_pmlN^AV_mUVTU_NJNmmVpApV_Ta_TaV_TvVTV]A_JNA_LN_UA_JNLilNiAlNL_Nmm measures. mJyINlmNJqlVpyV_JVLN_pmJa_pV_qNpaV_JlNAmNV_SlNkqN_Jyp UNiapN_pVA] for an incident to cause cascading and widespread impacts to critical infrastructure increases as well.
6.12.6 Vulnerability
Vulnerability in the context of cybersecurity refers to the susceptibility of digital systems paAppAJ\3UVmVmV_ŔqN_JNLIyIapUpNJU_a]aTVJA]A_LalTA_V|ApVa_A]SAJpalmV_J]qLV_T Iqp_ap]V^VpNLpaaqpLApNLmaSpwAlNalqmNaS]NTAJymympN^m V_mqSœJVN_piApJU ^A_ATN^N_pV_ALNkqApNmNT^N_pApVa_A_LLNSN_mN -in-LNipUmplApNTVNmA_L]AJ\aS cybersecurity training among personnel. Organizational challenges also contribute to JyINlmNJqlVpyvq]_NlAIV]VpyV_J]qLV_TIqp_ap]V^VpNLpaIqLT NpJa_mplAV_pm gaps in JaalLV_ApVa_ A_L lAiVL pNJU_a]aTy ALaipVa_ wVpUaqp JallNmia_LV_T mNJqlVpy protocols.
JJalLV_TpapUN3UlNApA_LA|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p30 avNliNai]N^AyINASSNJpNLIyA]AlTN -scale cybersecurity incident with cascading impacts to utilities. Over of those impacted in the THIRA scenario are estimated to UAvNAJJNmmA_LSq_JpVa_A]_NNLmA_LavNliNai]N are County of Los Angeles
All-Hazards Mitigation Plan
estimated to have ]V^VpNL_T]VmUilaœJVN_JyNiN_LV_Ta_pUNqpV]VpVNmASSNJpNL Iy the V_JVLN_pAwVLNmilNALA^aq_paSpUNiaiq]ApVa_Jaq]LINwVpUaq pqpV]VpymNlvVJN for an extended period. Addressing these vulnerabilities is essential to reduce the risk and potential disruption aSJyINlmNJqlVpyV_JVLN_pmJA]]V_TSalIapUpNJU_VJA]qiTlALNm and improved interagency coordination.
6.12.7 Impacts
3UNV^iAJpmaSJyINlmNJqlVpyV_JVLN_pmAlN^q]pVSAJNpNLASSNJp V_TNJa_a^VJmpAIV]Vpy iqI]VJmASNpyA_LJlVpVJA]V_SlAmplqJpqlNaiNlApVa_m
Direct Impacts:
x VmlqipVa_ aS JlVpVJA] mNlvVJNm NT UNA]pUJAlN N^NlTN_Jy lN mia_mN plA_mialpApVa_NpJ).
x Extended duration Continuity of Government or Continuity of Operations event. x Financial losses due to ransom payments remediation costsA_LiapN_pVA]]NTA] fees.
x Losscompromisealq_AqpUalV|NLlN]NAmN of sensitive data.
Indirect impacts:
x Erosion of public trust in digital services and affected institutions. x AmJALV_TNSSNJpma_iUymVJA]V_SlAmplqJpqlNNTiawNlTlVL wApNlmympN^m wAmpNwApNlNpJ
x Long-term economic repercussions from reduced competitiveness. x 3UNmVT_VœJA_pV^iAJpm —both direct and cascading—of cybersecurity incidents necessitate comprehensive mitigation and recovery strategies that address both technical and socioeconomic dimensions.
6.12.8 Summary
_mq^^AlyJyINlmNJqlVpyV_JVLN_pmlNilNmN_pA_Nva]vV_TA_LJ lVpVJA]pUlNAppUAp intersects with multiple aspects of community resilience and safety.
Ny3A\NAwAym
x yINlV_JVLN_pmAlNLy_A^VJmaiUVmpVJApNLA_LSAl-reaching in impact x They affect local systems despite their global nature County of Los Angeles
All-Hazards Mitigation Plan
x Historical trends and increasing digital dependency heighten both probability and vulnerability
x ^iAJpmNxpN_LINya_Lœ_A_JVA]]ammpaV_J]qLNmNlvVJNLVmlqipVa_A_L cascading infrastructure failures
yINlmNJqlVpyV_JVLN_pmLN^A_LAilaAJpVvNJaalLV_ApNLlNmia_m NpUApV_pNTlApNm robust technical defenses with cross-sector planning and recovery efforts. By q_LNlmpA_LV_TpUN_ApqlNmJaiNA_LiapN_pVA]Ja_mNkqN_JNmaS pUNmNV_JVLN_pm communities can build more resilient digital and physical infrastructures to safeguard against this growing threat.
County of Los Angeles
All-Hazards Mitigation Plan
6.13 Transportation Incidents
6.13.1 Nature
This section describes the inherent characteris tics of transportation incidents that can LVmlqippUNJa_pV_qaqmŔawaSiNai]NTaaLmA_LN^NlTN_JymNlv VJNmAJlamm!am Angeles County. Transportation incidents can be triggered by a variety of factors V_J]qLV_T _ApqlA] NvN_pm Uq^A_ Nllal A_L LN]VINlApN AJpmOther characteristics include:
x Affected Modes of Transportation: Incidents can involve any mode of transportation such as multi- vNUVJ]NJa]]VmVa_mUA|AlLaqm^ApNlVA]miV]]mlAV] LNlAV]^N_pmAvVApVa_incidentsA_L^AlVpV^NLVmlqipVa_m x Cascading Impacts: Disruptions to the transportation system often have the potential to trigger cascading failures due to the interconnected design of UVTUwAymlAV]_Npwal\mAVlialpmA_Lseaports.
x Contributing Factors: Incidents mayINV_ŔqN_JNLIyIapUilNLVJpAI]NSAJpalm NT rush-Uaql Ja_TNmpVa_ A_L q_ilNLVJpAI]N aJJqllN_JNm NT NxplN^N weather or infrastructure failure).
6.13.2 Location
3UNJaq_py¯m_Npwal\N_Ja^iAmmNmUVTUwAymlAV]AVlialpmialpmA_L]aJA]laALmpUAp are critical to regional mobility and commerce.
CCCouCouC ntynty ofo LoLos As Angengeeeeleslesleslelele AllAl
-
Hazazardar s MMMs Mitigatgg iononnn
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County of Los Angeles
All-Hazards Mitigation Plan
x Freeways: Los Angeles County boasts an extensive freeway system with over ^V]NmaSUVTU -capacity roads including corridors such as I- -
-
I-A_L-210.
x Major Transportation Hubs: The County is home to three commercial airports including Los Angeles International Airport (LAX) Long Beach Municipal Airport (LGB) and the Hollywood Burbank Airport (BUR) along with several general A v V A p V a _ A V l i a l p m 3 U N a q _ p y a w _ m A _ L a i N l A p N m l A J \ N p p V N ] L Vlialp
a^ipa_:aaL]NyVlialp1A_AIlVN]9A]]NyVlialpN_NlA]:V ]]VA^ ax VlœN]LA_L:UVpN^A_VlialpThe -alpmaS!am_TN]NmA_L!a_T NAJUwUVJU
are two of the busiest ports in the United States and vital for national and international tradeAlNA]maV_!am_TN]Nmaq_pyLLVpVa_A]]y!am_TN]Nm Union Station serves as the largest passenger rail station on the west coast. x %pUNl3lA_mialpApVa_#Npwal\m The county includes robust passenger rail busA_LiAlAplA_mVpmympN^mA]a_TwVpUSlNVTUplAV]mympN^m emerging mobility options such as taxis and rideshare services and enhanced bicycle networks. 3 UVmJa^ilNUN_mVvN_Npwal\VmpUNIAJ\Ia_NSalLAV]yJa^^qpV_T SlNVTUp ^avN^N_pA_LN^NlTN_JylNmia_mNAJlammpUNlNTVa_
6.13.3 Extent
The scope of transportation incidents spans multiple modes of travel and can have widespread consequences across the county’s integrated infrastructure. Road incidents may include multi- vNUVJ]N Ja]]VmVa_m UA|AlLaqm ^ApNlVA] miV]]m A_L laALwAy œlNm impacting multiple vehicles with potential delays in emergency responses. x 0AV]LVmlqipVa_mJA_V^iNLNJa^^qpNlA_LSlNVTUpmNlvVJNmV^iAJpV_TIapU]aJA] transit and regional connectivity.
x Air and maritime incidents—such as delays at major airports or disruptions at port facilities—JA_mVT_VœJA_p]yASSNJpJa^^NlJNmqii]yJUAV_mA_LiqI]VJmASNpy x Cascading effects across interconnected transportation modes may exacerbate Ja_TNmpVa_A_LmplAV_ALLVpVa_A]V_SlAmplqJpqlNmympN^mmqJUAm iawNlwApNl and emergency communications.
The extensive and interdependent nature of these networks means that an incident in a_NAlNAJA_kqVJ\]yV_ŔqN_JN^q]pVi]NplA_mialpApVa_mympN^m County of Los Angeles
All-Hazards Mitigation Plan
6.13.4 History
Los Angeles County has a long record of transportation-related incidents that have disrupted mobility and commerce.
x 9V_JN_p3Ua^Am
lVLTNVlN A semi-truck carrying lithium-ion batteries avNlpql_NLA_LJAqTUpœlNJAqmV_TpUNIlVLTNpaINJ]amNLSalmNvNlA]LAym x 2023 I-10 Freeway Fire: œlNV_AiA]]NpyAlLIN]awpUN -10 freeway in Downtown Los Angeles caused an eight-day closure for repairs and major cascading disruptions.
x 2020 Delta Air Lines Flight 89 Fuel Drop: 1Ualp]yASpNlpA\NaSSSla^!;A Boeing 777 encountered engine problems and conducted a fuel dump over iaiq]ApNLAlNAmV_[qlV_TavNl
iNai]Na_pUNTlaq_L
x UApmwalpU"Npla]V_\NlAV]^N_p A Metrolink passenger train collided wVpUA4_Va_-AJVœJSlNVTUpplAV_V_[qlV_TavNliNai]NA_LJAqmV_T LNApUm
x 2007 Newhall Pass Tunnel Fire: A multi-vehicle collision involving over 30 vNUVJ]NmJAqmNLAœlNwVpUV_pUNpq__N]V_[qlV_TiNai]NA_LJAqmV_TLNApUm The historical record reinforces the need to learn from previous events to enhance future preparedness and resilience.
6.13.5 Probability
The likelihood of transportation incidents in Los Angeles County remains elevated due to several converging factors V_J]qLV_TIqp_ap]V^VpNLpa x VTULAV]yplASœJva]q^Nma_SlNNwAymA_LAlpNlVA]mV_JlNAmNpU NlVm\aS^q]pV - vehicle accidents and congestion-related incidents.
x Aging infrastructure—V_J]qLV_TIlVLTNmlaALmqlSAJNmA_LlAV]mympN^m—creates AiNlmVmpN_plVm\aSSAV]qlNiAlpVJq]Al]yq_LNlNxplN^NwNApUN lJa_LVpVa_mA_L during peak usage periods.
x 3UNJaq_py¯mla]NAmA^A[alUqISalSlNVTUpA_LJa^^qpNlplASœJ^NA_mpUApNvN_ minor incidents can escalate rapidly into larger disruptions. x The frequent movement of hazardous materials and the increasing reliance on just-in-time delivery systems further elevate the risk of incidents with potentially severe consequences.
County of Los Angeles
All-Hazards Mitigation Plan
3aTNpUNlpUNmNSAJpalmJa_plVIqpNpaAJa_mVmpN_p]yUVTUilaIA IV]VpyaSplA_mialpApVa_ incidents impacting the region.
6.13.6 Vulnerability
The vulnerability of Los Angeles County’s transportation system is compounded by its interdependent design and its critical role in the regional economy. x Limited redundancy in key corridors means that a disruption on one freeway or rail line can quickly overload alternate routes.
x TV_T A_L avNlIqlLN_NL V_SlAmplqJpqlN Vm ]Nmm lNmV]VN_p pa NxplN^N NvN_pm leading to longer recovery times after incidents.
x The county’s economic dependence on uninterrupted transportation for daily Ja^^qpV_TA_LJa^^NlJVA]SlNVTUpV_JlNAmNmNxiamqlNpamVT_VœJA _p]ammNm during disruptions.
x a^i]Nx V_pNlLNiN_LN_JVNm INpwNN_ plA_mialpApVa_ mympN^m N^NlTN_Jy m N l v V J N m A _ L a p U N l J l V p V J A ] m N J p a l m ^ A \ N p U N _ N p w a l \ U V T U ] y m N_mVpVvN pa cascading failures.
3UVm mympN^VJ vq]_NlAIV]Vpy JA]]m Sal JaalLV_ApNL ^q]pV-agency efforts to bolster resilience and implement proactive mitigation measures.
6.13.7 Impacts
Transportation incidents can produce both immediate and long-lasting effects on iqI]VJmASNpyJa^^NlJNA_LavNlA]]kqA]VpyaS]VSN
1. 3lASœJA_L"aIV]Vpy Disruptions can lead to severe congestion affecting Uq_LlNLmaSpUaqmA_LmaSJa^^qpNlmA_LSlNVTUpvNUVJ]NmLN]AyV_TN^NlTN_Jy services and disrupting daily operations.
2. Economic Loss: Interruptions in the movement of goods and people can result V_mqImpA_pVA]œ_A_JVA]]ammNmV^iAJpV_T ]aJA]IqmV_NmmNm A_L pUNIlaALNl regional economy.
3. Public Safety: Extended delays in emergency response and Emergency Medical Services (EMS) transport times.
4. Cascading Disruptions: _ V _ J V L N _ p V _ a _ N ^ a L N N T A ^ A [ a l U V T U w A y J]amqlN JA_lVii]NpUlaqTUpUNplA_mialpApVa__Npwal\ASSNJpV _TlAV]AVlA_L maritime operations simultaneously and complicating recovery efforts.
These impacts highlight the critical need for robust mitigation strategies to manage both direct and indirect consequences of transportation incidents.
County of Los Angeles
All-Hazards Mitigation Plan
6.13.8 Summary
Los Angeles County’s transportation network is among the most extensive and complex V_ pUN _ApVa_ mNlvV_T ^V]]Va_m aS lNmVLN_pm A_L q_LNliV__V_T Av V p A ] N J a _ a ^ V J NJamympN^ 3UN LVvNlmN plA_mialpApVa_ ^aLNm wUV]N SAJV]VpApV_T ^aIV]Vpy A_L Ja^^NlJNA]maJlNApNvq]_NlAIV]VpVNmLqNpaavNl]AiiV_TV_SlAmplqJpqlNA_LUVTUplASœJ volumes.
x TV_TV_SlAmplqJpqlNJaqi]NLwVpUpUNJa_pV_qaqm^avN^N_paSU A|AlLaqm ^ApNlVA]mA_LpUNV_JlNAmV_TilNmmqlNmaSLAV]yqmATNJa_plVIq pNmpaAUVTU probability of incidents.
x Historical data demonstrate that even localized incidents can have far-reaching V^iAJpmV_J]qLV_Tila]a_TNLplASœJJa_TNmpVa_NJa_a^VJLVmlqi pVa_mA_L public safety challenges.
_Ja_J]qmVa_^VpVTApV_TplA_mialpApVa_V_JVLN_plVm\mV_!am _TN]Nmaq_pylNkqVlNm A_V_pNTlApNLJaq_pywVLNAiilaAJUpUApJa^IV_NmV_SlAmplqJpqlNqiTlALNmN_UA_JNL N^NlTN_Jy lNmia_mN A_L ilaAJpVvN ^AV_pN_A_JN mplApNTVNm LLlNmmV_T pUNmN challenges VmNmmN_pVA]pamASNTqAlLiqI]VJmASNpyN_mqlNNJa_a^VJmpAIV] VpyA_L maintain the region’s critical mobility infrastructure.
County of Los Angeles
All-Hazards Mitigation Plan
6.14 Public Health Emergencies
6.14.1 Nature
Public health emergencies in Los
Angeles County encompass a broad
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including infectious disease
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(CBRNE) hazards. Given the county's
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health hazards require a coordinated
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community partners.
Public health emergencies refer to
V _ J V L N _ p m p U A p i a m N A m V T _ V œ J A _ p threat to the health of a population.
These includeIqpAlN_ap]V^VpNLpa:
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County of Los Angeles
All-Hazards Mitigation Plan
x Vector-Ial_NLVmNAmNmNT:Nmp#V]N9Vlqm?V\A
x Foodborne and waterborne illnesses
x Chemical and radiological exposure
x Climate-lN]ApNLUNA]pUpUlNApmNTNxplN^NUNApiaalAVlkqA]VpywV]LœlNm The County of Los Angeles Department of Public Health (DPH) and the Emergency "NLVJA]1NlvVJNmTN_Jy"1 Ja]]AIalApNpa^a_VpalpUlNApmilNvN_paqpIlNA\mA_L mitigate impacts when emergencies arise.
6.14.2 Location and Extent
Los Angeles CountyUa^NpaavNl 9.7 ^V]]Va_lNmVLN_pmVmpUN^ampiaiq]aqmJaq_p y in the United States. Its diverse geography VNqlIA_JaAmpA]^aq_pAV_aqmA_LlqlA]) and demography lead to a range of public health vulnerabilities. - q I] V J U N A ] pU N ^ Nl TN _ J V N m J A _ a l V T V _ A pNS l a ^ ] a JA ] l NT V a _ A ] _ApVa_A] al T]aIA] maqlJNmV^iAJpV_TmiNJVœJ_NVTUIalUaaLmalpUNN_pVlNJaq_py 3UNNxpN_paSiqI]VJ health threats varies based on:
x 3UN_ApqlNaSpUNpUlNApmqJUAmplA_m^VmmVa_Ly_A^VJmalAvAV]AIV]VpyaS^NLVJA] countermeasures.
x Population density (higher risks in urban centers for communicable diseases) x Access to healthcare infrastructure
x _vVla_^N_pA]Ja_LVpVa_mAVlia]]qpVa_NxplN^NUNApNvN_pm
6.14.3 History
Public health emergencies in Los Angeles County have included:
x 2022 Monkeypox Outbreak
o iilaxV^ApN]y
JAmNmwNlNlNialpNLV_!am_TN]Nmaq_py
x COVID-19 Pandemic (2020–Present)
o %vNl ^V]]Va_ JAmNm
UamiVpA]V|ApVa_m A_L
LNApUm
reported in the county alone.
x 2018 Hepatitis A Outbreak
o -lV^AlV]yASSNJpV_Tq_UaqmNLiaiq]ApVa_m lNkqVlV_T^AmmvAJJV_ ApVa_ efforts.
x 2016-2017 West Nile Virus Outbreaks
o Multiple cases of mosquito-borne infections leading to severe illness and fatalities.
County of Los Angeles
All-Hazards Mitigation Plan
x 2015-2016 Zika Virus Outbreak
o No cases of local mosquito-Ial_NplA_m^VmmVa_IqppUNlNwNlNJAmNm lNialpNLV_pUNaq_pywVpUINV_TplAvN]-related.
x 2015 Meningococcal Disease Cluster
o An outbreak among men who have sex with men (MSM) led to a targeted vaccination campaign.
x #_ŔqN_|A-A_LN^VJ
o 3UaqmA_LmaSUamiVpA]V|ApVa_mmJUaa]mA_LIqmV_NmmNmASSNJpNL
6.14.4 Probability and Emerging Risks
3UN3UlNApA_LA|AlLLN_pVœJApVa_A_L0Vm\mmNmm^N_p30 VLN_pVœNm that pandemics and bioterrorism remain high-probability threats. Future public health risks also include:
x Emergence of infectious diseases driven by global travel and climate change. x Increased incidence of heat-related illnesses amid rising temperatures. x Increased prevalence of respiratory diseases due to declining air quality. x Rise of antimicrobial-resistant infections due to overuse of antibiotics.
The County of Los Angeles DPH continually assesses health threats and updates preparedness plans to address evolving concerns.
6.14.5 Vulnerability and Systemic Impacts
Certain populations in Los Angeles County may be disproportionately affected by public health emergencies:
x At-lVm\iaiq]ApVa_m^AyINLVSSNlN_pSalLVSSNlN_pUA|AlLmINSalN LqlV_TA_L after an emergency. It is important to assess each hazard in turn to identify those who may be disproportionately affected to improve preparedness and response efforts.
-qI]VJUNA]pUN^NlTN_JVNmmplAV_pUNUNA]pUJAlNmympN^LVmlqipNJa_a^VJAJpVvVpyA_L create mental health burdens. The 2024 THIRA report noted that:
x Healthcare infrastructure overload is a major concern during pandemics. x Potential economic loss from business closures during a prolonged public health crisis could exceed billions of dollars.
County of Los Angeles
All-Hazards Mitigation Plan
6.14.6 Mitigation Strategies and Preparedness Efforts
Los Angeles County employs several mitigation and preparedness strategies:
x Mass Vaccination Campaigns
o __qA] Ŕq mUapm %9 - vAJJV_ApVa_m A_L aqpIlNA\ -miNJVœJ immunization efforts.
x Points-of-Dispensing (POD) sites
o Disease Surveillance & Early Warning Systems
x Syndromic surveillance for emerging threats.
o Targeted sampling surveillance.
x Healthcare Infrastructure Strengthening
o Expanding hospital capacity Sal^NLVJA]mqlTN and emergency medical resources.
x Community Outreach & Public Health Education
o Disseminating critical information in multiple languages. x Emergency Stockpiles (Strategic National Stockpile(SNS)) o Ni]ay^N_paSA_pVIVapVJmA_pVvVlA]mA_LiNlma_A]ilapNJpVvNNkqVi^N_p (PPE) in crisis situations.
x Coordination with Federal & State Agencies
o Collaboration wVpU"A_LpUNA]VSal_VANiAlp^N_paS-qI]VJ Health to enhance response capabilities.
x Anthrax Threat Simulations
o The County of Los Angeles Metro system assessed as a high-risk area for bioterrorism response.
6.14.7 Summary
-qI]VJ UNA]pU N^NlTN_JVNm iamN mVT_VœJA_p JUA]]N_TNm paLos Angeles County V^iAJpV_TUNA]pUJAlNmympN^mvq]_NlAI]Niaiq]ApVa_mA_LNJa_a ^VJmpAIV]Vpy:UV]N the COVID-iA_LN^VJilavVLNLA^A[almplNmmpNmpSallNmia_mNNSSalpm a_TaV_T ilNiAlNL_NmmmqlvNV]]A_JNA_L^VpVTApVa_mplApNTVNmAV^pail apNJplNmVLN_pmSla^ future threats.
Ny3A\NAwAym
x Los Angeles County SAJNm LVvNlmN UNA]pU pUlNApm V_J]qLV_T iA_LN^VJm IVapNllalVm^A_LJ]V^ApN-related illnesses.
County of Los Angeles
All-Hazards Mitigation Plan
x Vulnerable populations may suffer disproportionate impacts during public health crises.
x -lNiAlNL_NmmNSSalpmSaJqma_mqlvNV]]A_JNvAJJV_ApVa_N^NlTN _JylNmia_mN and coordination with federal and state partners.
x qpqlNpUlNApmV_J]qLNN^NlTV_TV_SNJpVaqmLVmNAmNmUNAp-lN]ApNLV]]_NmmNmA_L antimicrobial resistance.
yJa_pV_qV_TV_vNmp^N_pmV_iqI]VJUNA]pUilNiAlNL_NmmLos Angeles County aims to reduce risks and strengthen resilience against future health emergencies.
County of Los Angeles
All-Hazards Mitigation Plan
7 Mitigation Strategy
County of Los Angeles
All-Hazards Mitigation Plan
7.1 Mitigation Strategy Overview
The Mitigation Strategy section of the All-Hazard Mitigation Plan (AHMP) presents Los Angeles County’s strategic blueprint for reducing risks and vulnerabilities posed over pUN]a_TpNl^AmmaJVApNLwVpUpUNUA|AlLmVLN_pVœNLV_pUNA|A lLLN_pVœJApVa_A nd 0Vm\mmNmm^N_pmNJpVa_3UNmplApNTVNmVLN_pVœNLV_pUVmmNJpV a_LlVvN^VpVTApVa_ activities based on existing capabilities wh ile also identifying areas of potential future V_vNmp^N_p pa IqV]L lNmV]VN_JN AJlamm Ja^^q_VpVNm JlVpVJA] SAJV]VpVNm A_L apher infrastructure within Los Angeles County.
7.2 Mitigation Goals and Objectives
Mitigation goals are the long-term vision that the County hopes to achieve by V^i]N^N_pV_TpUNvAlVaqm^VpVTApVa_mplApNTVNmLNmJlVINLV_pUVm"-AmwN]]AmpUN broad guidelines that have shaped mitigation strategy development. x aA] Protect life, property, infrastructure, the environment, and the economy pUlaqTUNkqVpAI]N^VpVTApVa_mplApNTVNmAV^NLAplNLqJV_TlVm\m of natural and human-caused hazards.
o Objective 1-_pNTlApNvq]_NlAI]Niaiq]ApVa_mV_J]qLV_TiNai]NwVpU JJNmmA_Lq_JpVa_A]#NNLm# V_papUNV^i]N^N_pApVa_aSA _y potential mitigation actions.
o Objective 1-2: Implement mitigation strategies that enhance resilience to LVmAmpNlV^iAJpmAJlammlNmVLN_pVA]AlNAmJa^^NlJVA]AlNAmV_SlAmplqJpqlN high-UA|AlLiapN_pVA]LA^mA_LapUNlJlVpVJA]SAJV]VpVNm o Objective 1- _Sal^ mplApNTVJ V_vNmp^N_pm V_ J]V^ApN ALAipApVa_ LNvN]ai^N_p A_L lNLNvN]ai^N_p pUAp AlN JN_pNlNL V_ NkqVpy A_L resilience.
x aA]_UA_JNJa^^q_Vpy-wide partnerships in hazard mitigation across all levels of government, the private sector, and the public. o Objective 2-1: Build a culture of disaster resilience and awareness of local UA|AlLmpUlaqTUiqI]VJN_TATN^N_pNLqJApVa_A_LaqplNAJU o Objective 2-2: Strengthen direct coordination among Los Angeles County Operational Area partners to unify efforts for mitigation activities. o Objective 2-3: Utilize a whole community approach to address disparities V_aqpJa^NmiamNLIypUNUA|AlLmVLN_pVœNLV_pUVm"- x aA] Enhance planning, response, and recovery through hazard VLN_pVœJApVa_AmmNmm^N_p^VpVTApVa_A_LlNmV]VN_JNAJpVvVpVNm County of Los Angeles
All-Hazards Mitigation Plan
o Objective 3-1: Establish and maintain coordination between hazard mitigation activities and other emergency management functions. o Objective 3-2: Integrate hazard mitigation activities into preparedness for future large-scale planned events within Los Angeles County. x aA]_mqlNN]VTVIV]VpySal"TlA_pSq_LV_Tpa^AxV^V|NN kqVpAI]N investment in hazard mitigation actions.
o Objective 4-1: Continue to meet all requirements for existing hazard mitigation grant programs used by the County.
o Objective 4-2: Expand the County’s ability to participate in grant programs not currently utilized by the County.
7.2.1 Changes in Mitigation Goals
The AHMP Advisory Committee reviewed the 2020 AHMP goals and updated them to lNŔNJppUN^ampJqllN_pCaq_pyJa_JNl_mA_LilValVpVNm3UNlNSalNpUN "-has
introduced new goals and objectives to build a more resilient community. Table 7-1 IN]aw Ja^iAlNmpUN
"-TaA]mwVpUilNvVaqm"-Ta A]mA]]apUNl
goals above are new goals and objectiv es developed by the AHMP Advisory Committee.
Mitigation priorities change through time depending on the type of disaster impacting !am_TN]Nmaq_pyvq]_NlAIV]VpypUNmplApNTVNmV^i]N^N_pNLAmwN]]AmapUNl_NNLm of the community. Priorities are also made based on current countywide Threat and Ha| A l L L N _ p V œ J A p V a _ A _ L 0 V m \ m m N m m ^ N _ p 3 0 m p q L V N m # A p V a _ A] 0Vm\ _LNx mmNmm^N_p1pApNA|AlL"VpVTApVa_-]A_1"- A_L other local plans and guides. The previous 2020 AHMP integrated hazard data into several operational plans including but not li ^VpNLpapUNN_NlA]-]A_%iNlApVa_A]lNA^NlTN_Jy%iNlApVa_ m-]A_ %%- amongst others. Addressing these changes will help to address Los Angeles County hazard priorities and to have mitigation strategies focused on the hazards that impact the region at most. The plan also added additional hazards and addressed a larger vulnerable population.
Table 7-"VpVTApVa_aA]4iLApNm
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2020 AHMP
aA]mSal
-2030
Planning Period
Changes
Build a culture and
practice disaster
resilience
Goal 2 (see above). aA]NxiA_LNL
previous goal
integrated as an
County of Los Angeles
All-Hazards Mitigation Plan
aA]mLLlNmmNLV_
2020 AHMP
aA]mSal
-2030
Planning Period
Changes
objective under Goal 2
in the current AHMP .
NppNli]A_SallNmia_L
paA_LlNJavNlSla^
hazards and disasters
V_J]qLV_TJ]V^ApNJUA_TN
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wV]LœlNpUApASSNJp!am
Angeles County.
Goal 3 (see above). Previous goal replaced
with new goal.
More successfully adapt
to hazards and disasters
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]A_Lm]VLNpmq_A^VA_L
wV]LœlNpUApASSNJp!am
Angeles County.
Goal 1 (see above). Previous goal replaced
with new goal.
7.3 Existing Mitigation Capabilities
The mitigation strategies developed as part of this AHMP seek to maximize existing ^VpVTApVa_JAiAIV]VpVNmVLN_pVœNLAmJqllN_p]yAvAV]AI]NwVpUV_pUN!am_TN]Nmaq_py %iNlApVa_A]lNA3UNmNNxVmpV_TJAiAIV]VpVNmUAvNINN_qiLApNLpalNŔNJpJUA_TNmV_ humA_pNJU_VJA]œ_A_JVA]]NTA]lNTq]ApalyNLqJApVa_A_LaqplNAJUlNmaqlJNmmV_JN the 2020 AHMP .
County of Los Angeles
All-Hazards Mitigation Plan
7.3.1qpUalVpVNm-a]VJVNmA_L!NTA]0NTq]Apaly0NmaqlJNm There are several NxVmpV_TAqpUalVpVNmia]VJVNmA_LapUNl]NTA]allNTq]ApalylNmaqlJNm applicable to hazard mitigation efforts in Los Angeles County. From the County Code aS%lLV_A_JNmpaJa^i]NpNLi]A_mpUNmNSal^pUNJal_Nlmpa_NaS UA|AlL^VpVTApVa_ activities by pro vVLV_TASaq_LApVa_laapNLV_LApAlNmNAlJUi]A__V_T3NJU_VJ A] Ecological Knowledge (TEK) provided by our state and locally recognized indigenous Ja^^q_VpVNmA_LN]NJpNLaSœJVA]m¯AqpUalVpyThe County aims to expand and improve upon pUNmNVLN_pVœNLJAiAIV]VpVNmIyALaipV_TpUVm"-a_JNAiilav NLV_papUN Safety Element of the Los Angeles County General Plan. This action will contribute to the County’s ability to be considered for an additional cost-share on Public Assistance projects through the California Disaster Assistance Act. Table 7-2 provides an overview aSNxVmpV_TJAiAIV]VpVNmlN]ApNLpaAqpUalVpVNmia]VJVNmA_L]NTA]lNTq]ApalylNmaqlJNm
Table 7-2 qpUalVpVNm-a]VJVNmA_L!NTA]0NTq]Apaly0NmaqlJNm Authority,
Policy, or
0NmaqlJN
Description Hazards
Addressed
Potential to
Affect
Development
Los Angeles
County
Operational
Area
Emergency
Operations
Plan (2023)
Establishes the coordinated
emergency management system
within the Los Angeles County
%iNlApVa_A]lNApailNiAlNSal
lNmia_LpaA_LlNJavNlSla^pUN
effects of large-scale emergencies
lNTAlL]NmmaSJAqmN]aJApVa_al
complexity.
All-Hazard No
Los Angeles
County General
Plan (2024)
Provides the policy framework for
how and where the
unincorporated County will grow
through the year 2035.
All-Hazard Yes Los Angeles
County
Comprehensive
Floodplain
0NvVNwmNxVmpV_TŔaaLi]AV_
management programs in the
County and recommends
enhancements to them through 35
Flood
Land
Movement
Yes
County of Los Angeles
All-Hazards Mitigation Plan
Authority,
Policy, or
0NmaqlJN
Description Hazards
Addressed
Potential to
Affect
Development
Management
Plan (2021)
mitigation actions. This plan is
currently being reviewed and
updated with completion targeted
for early 2026.
Los Angeles
County
Comprehensive
Floodplain
Management
Plan Repetitive
Loss Area
Analysis (2021)
Analyzes Repetitive Los Areas
within Los Angeles County and
Sq]œ]]ma^^q_Vpy0ApV_T1ympN^
requirements.
Flood
Land
Movement
Yes
County of Los
Angeles
Floodplain
Management
Plan Progress
Report (2024)
Provides an annual update on the
implementation of the action plan
VLN_pVœNLV_pUNa^ilNUN_mVvN
Floodplain Management Plan and
on the implementation and
evaluation of outreach projects.
Flood
Land
Movement
Yes
County of Los
Angeles
Repetitive Loss
Area Analysis
Progress Report
(2023)
Provide an annual update on the
implementation of the action plan
VLN_pVœNLV_pUNRepetitive Loss
Area Analysis to ensure there is a
continuing and responsive
planning process.
Flood Yes
Los Angeles
County Fire
Plan (2023)
NmJlVINmpUNwV]LœlN
N_vVla_^N_pUVmpalyA_LilN-œlN
management strategies to
N_UA_JNpUNilapNJpVa_aS]VvNm
ilaiNlpyA_L_ApqlA]lNmaqlJNm
Sla^wV]L]A_LœlN
:V]LœlN Yes
County of Los Angeles
All-Hazards Mitigation Plan
Authority,
Policy, or
0NmaqlJN
Description Hazards
Addressed
Potential to
Affect
Development
Los Angeles
County 2045
Climate Action
Plan (2024)
Delineates the County’s path
toward
meeting the goals of the Paris
Agreement and achieving carbon
neutrality for unincorporated
Los Angeles County.
:V]LœlN
Extreme
Heat
Drought
Flooding
Yes
Our County:
Los Angeles
Countywide
Sustainability
Plan (2019)
Outlines how local governments
and stakeholders can enhance the
well-being of all County
communities while adapting to
climate change and reducing
damage to the natural
N_vVla_^N_piAlpVJq]Al]ySaJqmV_T
on communities disproportionately
burdened by pollution.
:V]LœlN
Extreme
Heat
Drought
Flooding
Yes
Los Angeles
County
Floodplain
Management
Ordinance
Aims to minimize public and
ilVvApN]ammNmlNmq]pV_TSla^ŔaaL
conditions via uniformly applied
lNTq]ApVa_mV_ŔaaLila_N
^qLŔawalŔaaLlN]ApNLNlamVa_
areas.
Flood
Land
Movement
Yes
Los Angeles
County Code –
Title 32: Fire
Code
To build a new structure (or an
addition equal to or greater than
ÈaSNxVmpV_TmkqAlNSaapATN
the Los Angeles County Fire Code
lNkqVlNmlNvVNwaSVpm]aJApVa_pyiN
aSJa_mplqJpVa_paiaTlAiUym]aiN
amount and arrangement of
vNTNpApVa_A_LavNlA]]site
:V]LœlN Yes
County of Los Angeles
All-Hazards Mitigation Plan
Authority,
Policy, or
0NmaqlJN
Description Hazards
Addressed
Potential to
Affect
Development
settings—in order to create
defensible space necessary for
NSSNJpVvNœlNilapNJpVa_aSUa^Nm
in High Fire Severity Zones.
Los Angeles
County Code –
Title 22:
Planning and
Zoning
Establishes the regulations
governing land use and
LNvN]ai^N_pA_LLNœ_Nm|a_V_T
for unincorporated Los Angeles
County. Includes the Hillside
Management Area Ordinance
UAipNl pUN0NmVLN_pVA]
NmVT_1pA_LAlLm%lLV_A_JNA_L
the Hillside Design Guidelines.
These include requirements for
development in Hillside
"A_ATN^N_plNAmwUVJUAlN
LNœ_NLAmAlNAmwVpU
Èal
greater natural slopes. The
TqVLN]V_NmV_J]qLNmiNJVœJA_L
measurable design techniques that
JA_INAii]VNLpalNmVLN_pVA]
commerciA]V_LqmplVA]A_LapUNl
types of projects.
:V]LœlN
Earthquake
Land
Movement
Yes
Los Angeles
County Code –
Title 31: Green
Building
Standards
Code
Enhances the design and
construction of buildings via
building concepts with positive (or
reduced negative) environmental
V^iAJpmA_LN_JaqlATNm
sustainable construction practices
Extreme
Heat
Drought
Yes
County of Los Angeles
All-Hazards Mitigation Plan
Authority,
Policy, or
0NmaqlJN
Description Hazards
Addressed
Potential to
Affect
Development
AJlammi]A__V_TA_LLNmVT_
N_NlTyNSœJVN_JywApNl
Ja_mNlvApVa_^ApNlVA]A_L
lNmaqlJNNSœJVN_JyA_L
environmental air quality.
Los Angeles
County Brush
Clearance
Program
Legally declares both improved
and unimproved properties a
iqI]VJ_qVmA_JNA_LwUNlN
_NJNmmAlylNkqVlNmpUNJ]NAlA_JN
of hazardous vegetation thereby
creating defensible space for
NSSNJpVvNœlNilapNJpVa_aS
ilaiNlpy]VSNA_LpUNN_vVla_^N_p
The Brush Clearance Program is a
joint effort between the County of
Los Angeles Fire Department and
the County of Los Angeles
Department of Agricultural
Commissioner/Weights and
Measurem:NNLA|AlLA_L-Nmp
Abatement Bureau (Weed
Abatement Division).
:V]LœlN Yes
Los Angeles
County Code –
Title 26:
Building Code
Provides minimum standards to
regulate pUNLNmVT_Ja_mplqJpVa_
V_mpA]]ApVa_kqA]VpyaS^ApNlVA]m
qmNaJJqiA_Jy]aJApVa_A_L
^AV_pN_A_JNaSA]]IqV]LV_Tm
mplqJpqlNmTlALV_TA_LJNlpAV_
equipment. Regulates construction
Earthquake
:V]LœlN
Yes
County of Los Angeles
All-Hazards Mitigation Plan
Authority,
Policy, or
0NmaqlJN
Description Hazards
Addressed
Potential to
Affect
Development
near a known active earthquake
SAq]pUAipNl1NJpVa_ pUN
materials and construction
methods for construction in a
Wildland-Urban Interface (WUI)
VlNlNAUAipNl mplqJpqlA]
design as it relates to earthquake
UA|AlLmUAipNl1NJpVa_
16 lNiAVlaSJNlpAV_IqV]LV_TmV_
High Earthquake Damage Areas
UAipNl NAlpUkqA\NUA|AlL
reduction for concrete tilt-up
buildings (Chapter 95) and
unreinforced masonry buildings
UAipNl A^a_TapUNlm3UN
Building Code also includes
provisions for emergency housing
during a proclaimed emergency.
7.3.2 Human and Technical Resources
Existing human and technical resources across County Departments enable the aq_pypai]A_^A_ATNJa_LqJpA_LNxNJqpNVpmwVLNlA_TNaSUA|AlL^VpVTApVa_ activities. The resources below represent a high degree of expertise in all facets of hazard mitigation available to support mitigation activities. The County aims to NxiA_LA_LV^ilavNqia_pUNmNVLN_pVœNLJAiAIV]VpVNmIyNxiA_LV_Tpotential hazard training opportunities available to the Los Angeles County Operational Area. LLVpVa_A]]yAmvAlVaqmmpecial events are scheduled in Los Angeles County over the _NxpœvNyNAlmpUNaq_pyshould seek to expand coordination and technical resources lN]ApNLpa^AmmvVa]N_JNJyINlA_LapUNlmiNJVA]NvN_p-related hazards.
County of Los Angeles
All-Hazards Mitigation Plan
Table 7-3 provides an overview of existing capabilities related to human and technical resources.
Table 7-3 q^A_A_L3NJU_VJA]0NmaqlJNm
0NmaqlJN Department/Agency -lV_JViA]JpVvVpVNm0N]ApNLpaA|AlL Mitigation
Emergency
Management
Coordinator(s)
Los Angeles County
%SœJNaS^NlTN_Jy
Management
x Maintains and updates the Los
Angeles County Operational Area
Emergency Operations Plan and Los
Angeles County All-Hazard
Mitigation Plan.
x Coordinates local response and
recovery activities in the Emergency
Operation Center A_LV_pUNœN]L
x Wal\mJ]amN]ywVpU]aJA] mpApNA_L
federal partners to support planning
trainingNxNlJVmNiqI]VJV_Sal^ApVa_
and resource coordination.
_TV_NNlm
Building
_miNJpalm
Code
Enforcement
%SœJNlm VlN
"AlmUA]]mA_L
Other Technical
Staff
Los Angeles County
Public Works and Fire
Department
x %vNlmNNmpUNNSSNJpVvNNSœJVN_pSAVl
and safe enforcement of County of
Los Angeles Building and Fire
Codes.
_TV_NNlm
Construction
Project
"A_ATNlmA_L
Other Technical
Staff
Los Angeles County
Public Works
x Provides direct (or contract) JVvV]
mplqJpqlA]A_L^NJUA_VJA]
N_TV_NNlV_TmNlvVJNm including
Ja_plAJpila[NJpA_LJa_mplqJpVa_
management.
_TV_NNlm
Project
Los Angeles County
Public Works
x Maintains and operates a wide range
of local equipment and facilities and
assists members of the public by
County of Los Angeles
All-Hazards Mitigation Plan
0NmaqlJN Department/Agency -lV_JViA]JpVvVpVNm0N]ApNLpaA|AlL Mitigation
"A_ATNlm
Equipment
OiNlApalm
Maintenance and
Construction
StaffA_L%pUNl
Technical Staff
ilavVLV_TmqSœJVN_pJ]NA_SlNmUwApNl
reliable mNwNlmNlvVJNmmplNNp
^AV_pN_A_JNmpal^LlAV_ATN
mympN^mmplNNpJ]NA_V_TmplNNp]VTUpm
A_LplASœJmVT_A]m
Floodplain
Administrator
Los Angeles County
Public Works
x _SalJNmpUNŔaaLi]AV_^A_ATN^N_p
ordinance ensuring that
development proposals do not
V_JlNAmNŔaaLlVm\A_LpUAp_Nw
developments are not located below
the 100-yNAlŔaaL]NvN]_ALLVpVa_
pUNŔaaLi]AV_AL^V_VmplApalVm
responsible for planning and
^A_ATV_TŔaaLlVm\lNLqJpVa_
projects throughout Los Angeles
County.
-]A__Nlm
_TV_NNlm A_L
Technical Staff
Los Angeles County
Department of
Regional Planning
x Develops and maintains the Los
_TN]Nmaq_pyN_NlA]-]A_
including the Safety Element.
x Develops area plans based on the
Los Angeles County General Plan to
ilavVLN^alNmiNJVœJTqVLA_JNSal
pUNLNvN]ai^N_paS^alNmiNJVœJ
areas.
x 0NvVNwmilaiamNLLNvN]ai^N_p
JAiVpA]V^ilavN^N_pmA_LapUNl
physical projects involving property
for consistency and conformity with
the Los Angeles County General
Plan.
x Anticipates and acts on the need for
Aii]VJAI]N_Nwi]A_mia]VJVNmA_L
code changes.
County of Los Angeles
All-Hazards Mitigation Plan