San Francisco County Disaster Risk
San Francisco County, California
FEMA Risk Rating
Very High
National Percentile
100th
of 3,144 counties
State Rank
#8
of 58 (1 = highest risk)
Flood Risk
99th
percentile
Hazard Risk Breakdown
Flood
River, coastal, and surface flooding risk
Relatively High
Higher than 99% of US counties
Wildfire
Wildland and wildland-urban interface fire risk
Very Low
Higher than 29% of US counties
Tornado
Tornado and severe thunderstorm risk
Very Low
Higher than 35% of US counties
Earthquake
Seismic activity and ground shaking risk
Very High
Higher than 100% of US counties
Risk Overview
About Natural Disaster Risk in San Francisco County, California
San Francisco faces extreme earthquake and flood risk
San Francisco County's composite risk score of 99.52 ranks it as "Very High" and among the nation's riskiest counties, substantially above the typical U.S. baseline. Though it exceeds California's 88.72 average, the city's lower wildfire exposure (28.66) partially offsets other hazards.
Fifth-riskiest county in California overall
San Francisco ranks high statewide despite having California's lowest wildfire risk (28.66), because earthquake (99.78) and flood (98.60) risks are among the highest in the state. The city's dense, aging infrastructure magnifies disaster impacts.
Much riskier than rural inland Bay Area counties
San Francisco (99.52) vastly exceeds San Benito County (85.24) and approaches the extreme risk of Riverside and San Bernardino. Its urban concentration and proximity to the San Andreas Fault create concentrated hazard exposure unlike surrounding counties.
Earthquakes and flooding top the hazard list
San Francisco's earthquake risk (99.78) reflects the city's position on the San Andreas and Hayward faults—major seismic sources. Flood risk (98.60) is equally critical due to rising seas, aging levees, and bay flooding hazards affecting the urban core.
Earthquake insurance is critical; consider flood too
San Francisco homeowners must carry earthquake insurance given the city's extreme seismic risk and should evaluate flood coverage based on location—the Embarcadero and waterfront properties face particular inundation threats. Standard policies leave most residents dangerously exposed.
Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor
Preparedness Guide
What to Prepare for in San Francisco County
Top Hazards by Exposure
Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)
Risk Advisory: San Francisco County
Risk Verdict
At the 100th percentile nationally, San Francisco County faces one of the most concentrated natural disaster risk profiles of any U.S. county. San Francisco County's elevated composite score reflects cumulative multi-hazard exposure; households should prepare for the county's two or three primary hazard types.
Hazard Breakdown
Earthquake risk is San Francisco County's dominant natural hazard, ranked at the 100th percentile nationally under FEMA's National Risk Index. Flood ranks second at the 99th percentile nationally. Additional tracked hazards include tornado (35th percentile), wildfire (29th percentile).
Preparedness Context
At the 100th percentile nationally for earthquake risk, San Francisco County is in a zone where a post-earthquake communications plan matters almost as much as pre-earthquake structural preparation — phone networks are typically congested for hours after a significant event. Alongside earthquake exposure, San Francisco County's flood risk at the 99th percentile nationally reinforces the value of maintaining a household emergency supply cache usable for multiple hazard scenarios. For San Francisco County households, the three highest-impact earthquake preparedness actions are: (1) anchor heavy furniture and water heaters, (2) store three days of water at one gallon per person per day, and (3) identify a family reunification plan for the post-quake communication blackout period.
Regional Context
A composite score 10.8 points above the California state average puts San Francisco County in a higher-risk category than most counties in the state.
Is your household prepared for San Francisco County's hazards?
Review FEMA's county-specific preparedness checklists and emergency planning guides.
Frequently Asked Questions
What is the natural disaster risk in San Francisco County, CA?
What types of natural hazards affect San Francisco County?
How does San Francisco County risk compare to the California average?
Is San Francisco County at risk for earthquake?
How is natural disaster risk measured?
Why is San Francisco County higher risk than average?
Data Source
Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.
Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.