San Francisco survival atlas
San Francisco County, California
San Francisco’s biggest natural hazards are earthquakes, inland flooding and tsunamis. In FEMA’s National Risk Index they make up 99% of the natural-hazard risk for San Francisco County, home to all of San Francisco’s 826,079 residents. FEMA rates the county’s overall risk Very High. Here is what to do for each, step by step.
- People
- 826,079 Census estimate, July 1, 2025. No. 17 in the U.S.
- County
- San Francisco County All of San Francisco’s residents. FEMA rates counties, not cities.
- Overall risk
- Very High Score 99.52 of 100. No. 11 of the 30 largest U.S. cities.
- Expected loss
- $853 million A year, from all 18 natural hazards (FEMA estimate).
- Top 3 hazards
- 99% of the county’s risk comes from these three: Earthquake · Inland flooding · Tsunami.
What to do for San Francisco’s top hazards
The one rule to remember, then the first steps, word for word from our guides. Each guide lists its sources.
Earthquake
FEMA score 99.77: higher than 99.7% of U.S. counties. Expected loss $662 million a year.
- Drop to your hands and knees.
- Cover your head and neck, under a sturdy table if one is close.
- Hold on until the shaking stops. Don't run outside or stand in a doorway.
Inland flooding
FEMA score 98.60: higher than 98.6% of U.S. counties. Expected loss $178 million a year.
- Get to high ground now.
- Never walk, swim or drive into floodwater. 6 inches of moving water can knock you down; 12 inches carries away most cars.
- Car stalls in rising water: get out to higher ground if you safely can. Trapped in fast water: stay inside; if water rises inside, get on the roof.
Tsunami
FEMA score 72.30: higher than 72.3% of U.S. counties. Expected loss $6.0 million a year.
- Move inland or uphill on foot if you can. Keep going higher.
- The first wave may not be the last or the largest.
- Stay out of the zone until officials say it's safe. Danger can last hours or days.
All 18 natural hazards in San Francisco, ranked
Ranked by each hazard’s share of San Francisco County’s risk in FEMA’s National Risk Index. The score compares the county with every other U.S. county for that one hazard.
| # | Hazard | Share of risk | FEMA rating | Score | Expected loss a year | The rule |
|---|---|---|---|---|---|---|
| 1 | Earthquake | 78% | Very High | 99.77 | $662 million | Drop. Cover. Hold on. |
| 2 | Inland flooding | 21% | Relatively High | 98.60 | $178 million | Turn around, don't drown. |
| 3 | Tsunami | 0.7% | Relatively Moderate | 72.30 | $6.0 million | Strong or long shaking near the sea: go high now. |
| 4 | Heat wave | 0.5% | Relatively Moderate | 93.89 | $4.7 million | Get somewhere cool. Check on anyone who lives alone. |
| 5 | Landslide | <0.1% | Relatively High | 98.44 | $829,000 | Follow local alerts. Leave when officials say so. |
| 6 | Tornado | <0.1% | Relatively Low | 34.86 | $652,000 | Lowest floor, interior room, cover your head. |
| 7 | Coastal flooding | <0.1% | Relatively Moderate | 62.00 | $638,000 | Run from the water. Hide from the wind. |
| 8 | Drought | <0.1% | Relatively Moderate | 69.30 | $488,000 | Store water now: 1 gallon per person per day. |
| 9 | Lightning | <0.1% | Relatively Low | 29.86 | $104,000 | When thunder roars, go indoors. |
| 10 | Strong wind | <0.1% | Very Low | 10.30 | $74,000 | Shelter in an interior room, away from windows. |
| 11 | Hail | <0.1% | Very Low | 18.12 | $62,000 | Large hail coming? Get inside a sturdy building and away from the windows. |
| 12 | Wildfire | <0.1% | Very Low | 28.65 | $13,000 | Leave early. Know two ways out. |
| 13 | Volcanic activity | <0.1% | Very Low | 28.33 | $1 | Evacuate early. In ashfall, stay in and wear an N95. |
| 14 | Winter weather | <0.1% | Very Low | 1.20 | $0 | Stay in your shelter, or stay with your car. |
| – | Avalanche | – | Not applicable | – | – | Check your local avalanche center before backcountry travel. |
| – | Cold wave | – | No rating | – | – | One warm room. Never heat with an oven or a grill. |
| – | Hurricane | – | Not applicable | – | – | Know your evacuation zone. Told to go? Go early. |
| – | Ice storm | – | Not applicable | – | – | Stay off the roads. One warm room. |
Source // FEMA National Risk Index v1.20 (December 2025), county 06075. Rules: SOS.city survival guides.
How to read these numbers
- Share of risk. For each hazard, FEMA estimates the loss each year to buildings, people and farms, then adjusts it for social vulnerability and community resilience. The county’s overall risk is the sum of all 18, so the share shows how much of it each hazard carries.
- Score. A percentile from 0 to 100. A score of 99.5 means the county’s risk for that hazard is higher than 99.5% of U.S. counties.
- Rating. FEMA sorts counties into five groups, from Very Low to Very High.
- Big places rank high. Expected losses grow with the number of people and buildings exposed, so large urban counties rank high on many hazards. A high rating means plan for it, not that it will happen this year.
- County, not street. These ratings cover the whole county. For flood risk at your address, look it up on the FEMA Flood Map Service Center.
- San Francisco County is rated Relatively Moderate for social vulnerability and Very High for community resilience. Both feed into its overall rating.
Questions people ask
What natural disasters is San Francisco most at risk for?
San Francisco’s biggest natural hazards are earthquakes, inland flooding and tsunamis. In FEMA’s National Risk Index they make up 99% of the natural-hazard risk for San Francisco County, home to all of San Francisco’s 826,079 residents. FEMA rates the county’s overall risk Very High.
How does FEMA rate San Francisco’s overall disaster risk?
FEMA’s National Risk Index rates the overall risk of San Francisco County Very High, with a score of 99.52 out of 100. The score is a percentile: San Francisco County’s overall risk is higher than 99.5% of U.S. counties. Expected losses from natural hazards there average $853 million a year.
What should I do first to get ready in San Francisco?
Write down your top three: earthquakes, inland flooding and tsunamis. Turn on Emergency Alerts on every phone and sign up for your county’s alerts. Store water: 1 gallon per person per day for at least 3 days, 2 weeks if you can.
Sources
Every number on this page comes from these public datasets. We check them when we review the page.
- FEMA: National Risk Index data, county table (v1.20, December 2025)
- FEMA: National Risk Index frequently asked questions (December 2025)
- FEMA: National Risk Index for Natural Hazards
- U.S. Census Bureau: City and town population totals, 2020–2025 (Vintage 2025)
- Steps: What to do during an earthquake (SOS.city guide; its sources are listed on the page)
- Steps: What to do in a flood or flash flood (SOS.city guide; its sources are listed on the page)
- Steps: What to do if a tsunami is coming (SOS.city guide; its sources are listed on the page)
General safety information, not medical advice. In an emergency, call 911 and follow local officials.
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