Alameda County, CA
FEMA National Risk Index scores, disaster declarations & hazard data
Alameda County has experienced 24 federally declared disasters since 1970, most recently Severe Winter Storms, Flooding, And Mudslides in 2023. Its overall natural hazard risk is rated Very High — among the most at-risk counties in the country.
Alameda County's highest-rated hazards are earthquake, landslide, and inland flooding, with its top risk rated "Very High" by FEMA's National Risk Index. Recorded storm events have decreased 42% over the past five years compared to the prior five-year period.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Alameda County has been designated in 24 declarations since 1970, covering 9 disaster types including severe storm (8), flood (7), biological (2).
| Year | Type | Event name |
|---|---|---|
| 2023 | Severe Storm | Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, And Mudslides |
| 2023 | Flood | Severe Winter Storms, Flooding, Landslides, And Mudslides |
| 2023 | Flood | Severe Winter Storms, Flooding, And Mudslides |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 2017 | Flood | Severe Winter Storms, Flooding, And Mudslides |
| 2017 | Flood | Severe Winter Storms, Flooding, And Mudslides |
| 2017 | Severe Storm | Severe Winter Storms, Flooding, And Mudslides |
| 2006 | Severe Storm | Severe Storms, Flooding, Mudslides, And Landslides |
| 2006 | Severe Storm | Severe Storms, Flooding, Landslides, And Mudslides |
Showing the 10 most recent of 24 total declarations since 1970.
Source: FEMA OpenFEMA Disaster Declarations Summaries. A single disaster can produce more than one record per county. Data current through September 2026.
Risk by hazard type
| Hazard | Risk rating | Risk score | Recorded events | Deaths | Prop. damage |
|---|---|---|---|---|---|
| Wildfire | Relatively High | 97.7 | 0 | 0 | — |
| Inland Flooding | Very High | 99.7 | 144 | 1 | $150 |
| Coastal Flooding | Relatively High | 86 | 0 | 0 | — |
| Earthquake | Very High | 100 | 90 | — | — |
| Heat Wave | Relatively High | 97.6 | 16 | 0 | — |
| Tornado | Relatively Moderate | 65.8 | 0 | 0 | — |
| Hurricane | Not Applicable | — | 0 | 0 | — |
| Hail | Relatively Low | 35.8 | 19 | 0 | $5.0M |
| Strong Wind | Very Low | 11.3 | 0 | 0 | — |
| Winter Weather | Very Low | 4.3 | 0 | 0 | — |
| Ice Storm | Not Applicable | — | — | — | — |
| Cold Wave | No Rating | 0 | — | — | — |
| Lightning | Relatively Low | 47.5 | 1 | 0 | — |
| Drought | Relatively Moderate | 85.9 | 0 | 0 | — |
| Landslide | Relatively High | 99.8 | 14 | 0 | $10 |
| Avalanche | Very Low | 6.6 | — | — | — |
| Tsunami | Relatively Low | 60 | — | — | — |
| Volcanic Activity | Very Low | 78.8 | — | — | — |
Scores are 0–100 percentiles relative to all US counties — higher means more exposed, not that a disaster is likely this year. Event counts: NOAA Storm Events 2016–2026; earthquake counts from USGS ComCat (M3.0+, 1996–2026). See the methodology page for details.
Community vulnerability
Alameda County ranks in the 51st percentile (Moderate) for community vulnerability — a measure of how hard disaster impacts tend to hit residents. Higher vulnerability means more displacement, worse health outcomes, and slower recovery after a disaster.
| SVI theme | Percentile | Vulnerability level |
|---|---|---|
| Overall | 51st | Moderate |
| Socioeconomic status | 30th | Low |
| Household characteristics | 9th | Very low |
| Racial & ethnic minority status | 96th | High |
| Housing type & transportation | 92nd | High |
Source: CDC/ATSDR Social Vulnerability Index 2022. Percentiles compare counties nationally — higher means more vulnerable relative to other counties. See CDC SVI for full methodology.
Future risk outlook
| Wildfire metric | National percentile | Level |
|---|---|---|
| Burn probability | 97th | Very High |
| Risk to homes | 97th | Very High |
| Buildings in direct exposure zone | 5.4% | — |
NOAA tracked 189 weather events in this county over 2016–2025: 120 in 2016–20 vs 69 in 2021–25 (-42% — frequency decreasing).
Wildfire: USDA Forest Service Wildfire Risk to Communities (RDS-2020-0016-2) — modeled values, not annual forecasts. See wildfirerisk.org. Inland flood and heat projections pending data availability; coastal sea-level projections are available for select coastal counties below — see the data page.
Nearby counties
Frequently asked questions
What natural hazards pose the greatest risk in Alameda County?
According to the FEMA National Risk Index, the highest-risk hazards in Alameda County, California are earthquake, landslide, and inland flooding. The county's overall natural hazard risk is rated Very High — among the most at-risk counties in the country.
Has Alameda County received federal disaster declarations?
Yes. Alameda County has received 24 federal disaster declarations since 1970, including declarations in 2023. The most common disaster type on record is severe storm (8 declarations).
Has Alameda County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Alameda County since the start of 2024. Its most recent declaration on record is Severe Winter Storms, Flooding, And Mudslides in 2023.
How does Alameda County's natural hazard risk compare to nearby counties?
Among neighboring counties, Santa Clara County, CA has the highest overall natural hazard risk (Very High) and Solano County, CA has the lowest (Relatively High). Alameda County is rated Very High overall.
How is Alameda County's composite disaster risk index calculated?
Alameda County's composite disaster risk index — officially FEMA's National Risk Index (NRI) — scores every US county on a 0–100 percentile scale across 18 natural hazard types, factoring in expected annual loss, social vulnerability, and community resilience. Alameda County's composite score of 100 means its overall natural hazard risk is higher than 100% of US counties.