San Antonio survival atlas
Bexar County, Texas
San Antonio’s biggest natural hazards are inland flooding, tornadoes and hail. In FEMA’s National Risk Index they make up 90% of the natural-hazard risk for Bexar County, home to nearly all of San Antonio’s 1.5 million residents. FEMA rates the county’s overall risk Relatively High. Here is what to do for each, step by step.
- People
- 1,548,422 Census estimate, July 1, 2025. No. 7 in the U.S.
- County
- Bexar County Nearly all of San Antonio’s residents. FEMA rates counties, not cities.
- Overall risk
- Relatively High Score 99.42 of 100. No. 8 of the 10 largest U.S. cities.
- Expected loss
- $619 million A year, from all 18 natural hazards (FEMA estimate).
- Top 3 hazards
- 90% of the county’s risk comes from these three: Inland flooding · Tornado · Hail.
What to do for San Antonio’s top hazards
The one rule to remember, then the first steps, word for word from our guides. Each guide lists its sources.
Inland flooding
FEMA score 99.65: higher than 99.6% of U.S. counties. Expected loss $365 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.
Tornado
FEMA score 99.90: higher than 99.9% of U.S. counties. Expected loss $124 million a year.
- Go to the lowest floor: a small interior room away from windows.
- Cover your head and neck.
- In a mobile home or a car: get to a sturdy building.
Hail
FEMA score 99.93: higher than 99.9% of U.S. counties. Expected loss $72.3 million a year.
We don’t have a full hail guide yet. Follow local alerts and officials.
Heat wave
FEMA score 99.38: higher than 99.3% of U.S. counties. Expected loss $39.2 million a year.
- Use air conditioning, or go to a library, mall or cooling center.
- Heat stroke signs: confusion, slurred speech, collapse; hot, dry or soaked skin; 103°F or higher.
- Call 911.
All 18 natural hazards in San Antonio, ranked
Ranked by each hazard’s share of Bexar 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 | Inland flooding | 59% | Very High | 99.65 | $365 million | Turn around, don't drown. |
| 2 | Tornado | 20% | Very High | 99.90 | $124 million | Lowest floor, interior room, cover your head. |
| 3 | Hail | 12% | Very High | 99.93 | $72.3 million | Get indoors, away from windows. |
| 4 | Heat wave | 6.3% | Relatively High | 99.38 | $39.2 million | Get somewhere cool. Check on anyone who lives alone. |
| 5 | Cold wave | 1.5% | Relatively High | 94.75 | $9.5 million | One warm room. Never heat with an oven or a grill. |
| 6 | Hurricane | 0.4% | Relatively Moderate | 83.52 | $2.7 million | Know your evacuation zone. Told to go? Go early. |
| 7 | Lightning | 0.3% | Relatively High | 96.46 | $1.9 million | When thunder roars, go indoors. |
| 8 | Wildfire | 0.3% | Relatively Moderate | 92.36 | $1.7 million | Leave early. Know two ways out. |
| 9 | Strong wind | 0.2% | Relatively High | 87.05 | $1.5 million | Shelter in an interior room, away from windows. |
| 10 | Earthquake | <0.1% | Relatively Low | 61.89 | $437,000 | Drop. Cover. Hold on. |
| 11 | Drought | <0.1% | Relatively Moderate | 69.52 | $435,000 | Store water now: 1 gallon per person per day. |
| 12 | Ice storm | <0.1% | Relatively Moderate | 79.14 | $324,000 | Stay off the roads. One warm room. |
| 13 | Winter weather | <0.1% | Relatively High | 88.28 | $311,000 | Stay in your shelter, or stay with your car. |
| 14 | Landslide | <0.1% | Relatively Low | 85.17 | $26,000 | Follow local alerts. Leave when officials say so. |
| – | Avalanche | – | Not applicable | – | – | Check your local avalanche center before backcountry travel. |
| – | Coastal flooding | – | Not applicable | – | – | Run from the water. Hide from the wind. |
| – | Tsunami | – | Not applicable | – | – | Strong or long shaking near the sea: go high now. |
| – | Volcanic activity | – | Not applicable | – | – | Evacuate early. In ashfall, stay in and wear an N95. |
Source // FEMA National Risk Index v1.20 (December 2025), county 48029. Rules: SOS.city survival guides.
The rest of San Antonio
San Antonio also reaches into 1 other county, which FEMA rates separately.
| County | San Antonio residents | Overall FEMA rating | Top 3 hazards by share of risk |
|---|---|---|---|
| Medina County | 11 | Relatively Low (68.70) | Inland flooding, Tornado, Drought |
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.
- Bexar County is rated Relatively Moderate for social vulnerability and Relatively Low for community resilience. Both feed into its overall rating.
Questions people ask
What natural disasters is San Antonio most at risk for?
San Antonio’s biggest natural hazards are inland flooding, tornadoes and hail. In FEMA’s National Risk Index they make up 90% of the natural-hazard risk for Bexar County, home to nearly all of San Antonio’s 1.5 million residents. FEMA rates the county’s overall risk Relatively High.
How does FEMA rate San Antonio’s overall disaster risk?
FEMA’s National Risk Index rates the overall risk of Bexar County Relatively High, with a score of 99.42 out of 100. The score is a percentile: Bexar County’s overall risk is higher than 99.4% of U.S. counties. Expected losses from natural hazards there average $619 million a year.
What should I do first to get ready in San Antonio?
Write down your top three: inland flooding, tornadoes and hail. 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 in a flood or flash flood (SOS.city guide; its sources are listed on the page)
- Steps: What to do in a tornado warning (SOS.city guide; its sources are listed on the page)
- Steps: What to do in extreme heat and heat stroke (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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