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Sonoma County Hazard Mitigation Plan
VOLUME I—BASIC PLAN
May 2026
Prepared For
County of Sonoma | Department of Emergency Management
2300 County Center Drive, Suite B220, Santa Rosa, CA 95403 707-565-1152 | www.sonomacounty.gov
Prepared By
Tetra Tech, Inc. | Emergency Management, Risk & Resilience 2301 Lucien Way #120, Maitland, FL 32751
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Sonoma County Hazard Mitigation Plan
Executive Summary iii
EXECUTIVE SUMMARY
Hazard Mitigation Overview
Hazard mitigation is the use of long-term and short-term policies, programs, projects, and other activities to minimize the loss of life, injury, and property damage that can result from a disaster.
Communities, residents, and businesses across the United States have been faced with continually increasing costs associated with natural and human-caused hazards. Hazard mitigation is the first step in reducing risk and is the most effective way to reduce costs associated with hazards.
Sonoma County developed a hazard mitigation plan (HMP) to reduce risks from disasters to the people, property, economy, and environment within the County. Developed by the County and other participating local jurisdictions (the Planning Partners), this HMP updates the 2021 Sonoma County HMP. It includes countywide assessment of hazards, risk, and capabilities. The plan complies with federal and state hazard mitigation planning requirements to establish the Planning Partners’ eligibility for funding under Federal Emergency Management Agency (FEMA) grant programs. The following are the jurisdictions in Sonoma County that participated as Planning Partners:
• County of Sonoma
• City of Cloverdale
• City of Cotati
• City of Healdsburg
• City of Petaluma
• City of Rohnert Park
• City of Santa Rosa
• City of Sebastopol
• City of Sonoma
• Town of Windsor
• Bodega Bay Public Utility District
• Cloverdale Fire Protection District
• Gold Ridge Fire Protection District
• North Sonoma Coast Fire Protection District
• Northern Sonoma County Fire Protection District
• Rancho Adobe Fire Protection District
• Santa Rosa Junior College
• Sonoma County Agricultural Preservation and Open
Space District (Ag + Open Space)
• Sonoma County Fire Protection District
• Sonoma Valley Fire Protection District
• Sonoma Water
• Timber Cove Fire Protection District
The Planning Process
Overall Approach
To support the planning process, the Planning Partners accomplished the following:
• Developed a Hazard Mitigation Working Group (HMWG) consisting of key County and regional partners and stakeholders
• Reviewed the 2021 Sonoma County Hazard Mitigation Plan Sonoma County Hazard Mitigation Plan
Executive Summary iv
• Identified hazards of concern to be included in the update • Profiled the hazards of concern
• Estimated the inventory at risk and potential losses associated with these hazards • Reviewed and updated the mitigation goals and objectives • Reviewed mitigation strategy and actions outlined in the 2021 HMP to determine progress • Developed new mitigation actions to reduce the vulnerability of assets from hazards of concern • Involved a wide range of stakeholders and the public in the plan update process • Developed mitigation plan maintenance procedures to be executed after obtaining approval of the plan from the California Governor’s Office of Emergency Services (Cal OES) and FEMA • Formally created the planning process through the governing board and participating jurisdictions
Multiple Agency Support for Hazard Mitigation
Primary responsibility for hazard mitigation lies with local governments. Partners at the regional, state, and federal levels are available to assist local communities with their mitigation strategies. FEMA provides grants, tools, guidance, and training to support mitigation planning. In California, Cal OES is the lead agency providing hazard mitigation planning assistance to local jurisdictions.
The participating jurisdictions provided significant input into the preparation of this HMP, in particular the preparation of jurisdiction-specific annexes included in Volume II. They fully coordinated with and solicited participation from county and local governments, relevant organizations and groups, state and federal agencies, and the general public. This coordination ensured that stakeholders had established communication channels and relationships to support mitigation planning and mitigation actions included in the plan.
Under the project management of the Sonoma County Department of Emergency Management, the Sonoma County HMWG provided oversight for the preparation of this plan. The HMWG includes representatives from the following:
• Ag + Open Space
• CAL FIRE
• City of Cotati
• City of Petaluma
• City of Santa Rosa
• Permit Sonoma (Sonoma County’s
community planning department)
• Regional Climate Protection Authority
• Sonoma County Administrator’s Office
• Sonoma County Community
Development Commission
• Sonoma County Community Organizations
Active in Disaster
• Sonoma County Department of Emergency
Management
• Sonoma County Department of Health Services
• Sonoma County Office of Equity
• Sonoma County Public Infrastructure
• Sonoma Economic Development Collaborative
• Sonoma Water
• Town of Windsor
• Western Builders
Sonoma County Hazard Mitigation Plan
Executive Summary v
Risk Assessment for Local Hazards of Concern
The Planning Partners evaluated each jurisdiction’s risk and vulnerability due to each of the hazards of concern, based on past events, past and predicted future losses, and the expected probability of future occurrence. From these evaluations, hazards were ranked as high, medium, or low risk to each jurisdiction. The hazard rankings were used to focus and prioritize individual jurisdictional mitigation strategies. Summary overall hazard rankings for all of Sonoma County are shown in Figure ES-1.
Figure ES-1. Countywide Hazard Ranking
Capability Assessment and Plan Integration into Other Local Mechanisms
Effective mitigation is achieved when hazard awareness and risk management become integral parts of public activities and decision-making. Sonoma County has many plans and programs that support hazard risk management. This HMP integrates, complements, and references those plans and programs to the extent practical in order for it to be a comprehensive resource for hazard mitigation.
The HMP includes a capability assessment to review relevant local mechanisms for each participating jurisdiction. This assessment identifies where each jurisdiction is currently able to implement hazard mitigation measures and where each would benefit from improved capabilities for such measures. The capability assessment also provides a summary and description of the existing plans, programs, and regulatory mechanisms at all levels of government (federal, state, county and local) that support hazard mitigation in the County. In the jurisdictional annexes, each participating jurisdiction identifies how it has integrated hazard risk management into its existing planning, regulatory and operational/administrative framework, and how it intends to continue to promote this integration.
High Risk
Earthquake
Wildfire
Medium Risk
Drought
Extreme Cold
Extreme Heat
Extreme Wind
Flood
Low Risk
Dam Failure
Landslide
Sea Level Rise
Tsunami
Sonoma County Hazard Mitigation Plan
Executive Summary vi
Mitigation Strategy
Hazard Mitigation Plan Goals and Objectives
The HMP includes mitigation goals for reducing or avoiding long-term vulnerabilities to the identified hazards of concern. The planning process included a review and update of previous mitigation goals and objectives developed to guide the selection of mitigation actions. The goals and objectives were updated based on the updated risk assessment, discussions, research, and input from plan participants and stakeholders. The goal development process considered the goals expressed in the 2023 California State Hazard Mitigation Plan, as well as other relevant county and local planning documents.
The following goals were identified for this HMP:
• Goal 1—Protect people and minimize loss of life and injury. • Goal 2—Minimize potential for loss of property, economic and social impacts, and displacement due to hazards.
• Goal 3—Minimize potential for environmental impacts and consider a broad-range of mitigation strategies, including nature-based solutions where feasible. • Goal 4—Communicate and improve public understanding of natural hazard risk to the whole community within Sonoma County.
• Goal 5—Support the advancement of effective mitigation policies, programs, and projects that are adaptive, proactive, cost-effective, and environmentally sustainable to build a resilient Sonoma County.
• Goal 6—Enhance the capability/capacity of the Sonoma County planning area to prepare, respond, and recover from the impact of natural hazards.
Implementation of the 2021 Plan
The status of the mitigation projects identified in the 2021 HMP was reviewed for this HMP. Numerous projects and programs have been implemented that have reduced hazard vulnerability to assets in the planning area. Uncompleted projects have been revaluated, modified as necessary, and incorporated into this plan. The Planning Partners’ annexes describe these mitigation activities in more detail, and plan maintenance procedures have been developed to encourage thorough integration with local decisions and processes and regular review of implementation progress. 2026 Mitigation Strategy
Sonoma County and the participating jurisdictions identified 410 mitigation actions to pursue over the next five years. Actions chosen represent a wide variety of project types across the eleven hazards of concern. The mitigation strategy for each jurisdiction is available in the annexes of Volume II.