Sierra County, CA
FEMA National Risk Index scores, disaster declarations & hazard data
Sierra County has experienced 16 federally declared disasters since 1965, most recently Severe Winter Storms, Flooding, Landslides, And Mudslides in 2023. Its overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Sierra County's highest-rated hazards are wildfire, landslide, and lightning, with its top risk rated "Relatively Moderate" by FEMA's National Risk Index.
Past disasters & FEMA designations
A federal disaster declaration officially designates a county for FEMA disaster assistance. Sierra County has been designated in 16 declarations since 1965, covering 6 disaster types including flood (6), severe storm (5), 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 |
| 2020 | Fire | Wildfires |
| 2020 | Biological | Covid-19 Pandemic |
| 2020 | Biological | Covid-19 |
| 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 |
| 2005 | Hurricane | Hurricane Katrina Evacuation |
| 1997 | Severe Storm | Severe Storms, Flooding, Mud And Landslides |
Showing the 10 most recent of 16 total declarations since 1965.
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 Moderate | 95.6 | 0 | 0 | — |
| Inland Flooding | Relatively Low | 37.7 | 2 | 0 | $6.8M |
| Coastal Flooding | Not Applicable | — | 0 | 0 | — |
| Earthquake | Relatively Low | 66.8 | 58 | — | — |
| Heat Wave | Very Low | 7.5 | 0 | 0 | — |
| Tornado | Very Low | 2.4 | 0 | 0 | — |
| Hurricane | Not Applicable | — | 0 | 0 | — |
| Hail | Very Low | 3.4 | 0 | 0 | — |
| Strong Wind | Very Low | 2.4 | 0 | 0 | — |
| Winter Weather | Relatively Low | 33.2 | 0 | 0 | — |
| Ice Storm | Not Applicable | — | — | — | — |
| Cold Wave | No Rating | 0 | — | — | — |
| Lightning | Relatively Moderate | 77.6 | 1 | 1 | — |
| Drought | Relatively Low | 35.9 | 0 | 0 | — |
| Landslide | Relatively Moderate | 94.6 | 3 | 0 | $1.6M |
| Avalanche | Very Low | 44.9 | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
| Volcanic Activity | Very Low | 45.9 | — | — | — |
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
Sierra County ranks in the 35th percentile (Low) 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 | 35th | Low |
| Socioeconomic status | 60th | Moderate |
| Household characteristics | 26th | Low |
| Racial & ethnic minority status | 39th | Low |
| Housing type & transportation | 17th | Very low |
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 | 99th | Very High |
| Risk to homes | 100th | Very High |
| Buildings in direct exposure zone | 76.4% | — |
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 Sierra County?
According to the FEMA National Risk Index, the highest-risk hazards in Sierra County, California are wildfire, landslide, and lightning. The county's overall natural hazard risk is rated Very Low — among the lowest-risk counties in the country.
Has Sierra County received federal disaster declarations?
Yes. Sierra County has received 16 federal disaster declarations since 1965, including declarations in 2023. The most common disaster type on record is flood (6 declarations).
Has Sierra County had any FEMA disaster declarations in 2024, 2025, or 2026?
No federal disaster declarations have been recorded for Sierra County since the start of 2024. Its most recent declaration on record is Severe Winter Storms, Flooding, Landslides, And Mudslides in 2023.
How does Sierra County's natural hazard risk compare to nearby counties?
Among neighboring counties, Placer County, CA has the highest overall natural hazard risk (Relatively Moderate) and Storey County, NV has the lowest (Very Low). Sierra County is rated Very Low overall.
How is Sierra County's composite disaster risk index calculated?
Sierra 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. Sierra County's composite score of 32 means its overall natural hazard risk is higher than 32% of US counties.