Natural disaster risk in Contra Costa County, California
California · population 1,165,466 · FIPS 06013
Overall: very high risk
Contra Costa County has a composite risk score of 99.5 out of 100 — among the highest 1% of US counties. It ranks 8 of 58 in California (1 = highest risk). Its highest-rated hazards are inland (riverine) flooding, earthquake, landslide.
Drought now: No: no drought or dryness
No. On the U.S. Drought Monitor map valid 13 October 2026, no part of Contra Costa County is in drought or abnormally dry (none of D0 to D4). That has been so for 25 weeks in a row.
Drought in Contra Costa County: the last 52 weeks · droughtmonitor.unl.edu
The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration. Map courtesy of NDMC.
Risk, loss, vulnerability and resilience
| Measure | Rating and score |
|---|---|
| Overall risk Expected annual loss, adjusted for social vulnerability and community resilience. |
Very high 99.5 |
| Expected annual loss About $970.5 million a year, on average, across all 18 hazards. |
Relatively high 99.6 |
| Social vulnerability Higher means people may find it harder to prepare and recover. |
Relatively low 21.5 |
| Community resilience Higher means a stronger ability to prepare, adapt and recover. |
Relatively high 67.8 |
Risk by hazard
FEMA's risk rating for each of 18 natural hazards in Contra Costa County, highest first. "Not applicable" means the hazard is not modelled here.
| Hazard | Risk rating and score |
|---|---|
| Inland (riverine) flooding | Very high 99 |
| Earthquake | Relatively high 99 |
| Landslide | Relatively high 99 |
| Heat wave | Relatively high 98 |
| Drought | Relatively high 94 |
| Lightning | Relatively high 90 |
| Wildfire | Relatively moderate 97 |
| Coastal flooding | Relatively moderate 66 |
| Tornado | Relatively low 49 |
| Tsunami | Relatively low 47 |
| Strong wind | Relatively low 34 |
| Volcanic activity | Very low 77 |
| Hail | Very low 33 |
| Winter weather | Very low 9 |
| Avalanche | Very low 5 |
| Cold wave | No rating |
| Hurricane | Not applicable |
| Ice storm | Not applicable |
FEMA disaster declarations for Contra Costa County
Federal declarations that designated Contra Costa County, since 1 Jan 2024 (the period this site keeps from OpenFEMA). Older declarations are in FEMA's own dataset.
Not since 1 Jan 2024: no FEMA disaster declaration in the records this site read names Contra Costa County.
All FEMA declarations in California, with estimated apply-by dates · Open FEMA deadlines
This product uses the Federal Emergency Management Agency's OpenFEMA API, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s). Dataset: Disaster Declarations Summaries - v2.
How to read these ratings
- Ratings run in five steps: very low, relatively low, relatively moderate, relatively high and very high. They compare a county with every other US county; they are not a measure of danger on their own.
- Scores run from 0 to 100 and are national percentiles. The bar shows the score: a score of 80 means a higher value than 80% of US counties.
- Overall risk combines the expected annual loss with social vulnerability and community resilience.
- Expected annual loss is the average yearly loss to buildings, people and agriculture the model expects from all 18 hazards.
- Social vulnerability describes how hard it may be for people to prepare for and recover from a disaster. Higher is worse.
- Community resilience describes a community's ability to prepare, adapt and recover. Higher is better.
- "Not applicable" means FEMA does not model that hazard there (for example, hurricanes far inland).
About this data
Source: FEMA National Risk Index, version 1.20, released December 2025, published by the Federal Emergency Management Agency (US public domain). About the National Risk Index. The index is a model of relative risk built from historical hazard records, what is exposed and community factors. It is not a forecast, it does not describe any single property, and it is not insurance or financial advice. For decisions about a specific address, check FEMA's flood maps and your local emergency management office.
Questions
What is the natural disaster risk in Contra Costa County, California?
FEMA's National Risk Index rates the overall risk in Contra Costa County as very high, with a score of 99.5 out of 100 (among the highest 1% of US counties). That is a comparison with other US counties, not a forecast.
What are the biggest natural hazards in Contra Costa County?
The hazards rated highest for Contra Costa County are inland (riverine) flooding (very high), earthquake (relatively high), landslide (relatively high).
What is the flood risk in Contra Costa County?
FEMA rates inland (river and rain) flooding risk in Contra Costa County as very high, and coastal flooding risk as relatively moderate. For a specific property, check the FEMA flood map and your local floodplain office.
Has Contra Costa County had a FEMA disaster declaration?
Not since 1 Jan 2024: no FEMA disaster declaration in the records this site read names Contra Costa County.
Is Contra Costa County in a drought?
No. On the U.S. Drought Monitor map valid 13 October 2026, no part of Contra Costa County is in drought or abnormally dry (none of D0 to D4). That has been so for 25 weeks in a row.
Every county in California, ranked · All states · Disasters near me