Sierra County, California: Natural Disaster Risk and History
Sierra County, California has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 31.5 out of 100, higher than about 31% of US counties, with wildfires, landslides and lightning scoring highest of its 18 hazards and $8.4 million a year in expected losses.
OpenFEMA lists 14 federal disaster declarations that included Sierra County since 1964, not counting 2 for COVID-19; the latest is DR-4699-CA (Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared 3 April 2023). NOAA's Storm Prediction Center has no tornado on record touching Sierra County from 1950 to 2025.
Live weather alerts for California All official warnings Latest FEMA declarations
Population 3,200 Buildings worth $1.1 billion Area 972 sq mi Risk rank in California 57 of 58 FIPS 06091
All 18 hazards, highest risk first
FEMA National Risk Index| Hazard | Risk rating | Score | Expected loss a year | How often | Events in record |
|---|---|---|---|---|---|
| Wildfire | Relatively Moderate | 95.6 | $3.5 million | about once every 65 years | — |
| Landslide | Relatively Moderate | 94.6 | $97,489 | about 3 a year | — |
| Lightning | Relatively Moderate | 77.6 | $538,295 | about 16 a year | 15,429 strikes |
| Earthquake | Relatively Low | 66.8 | $552,245 | about once every 23 years | — |
| Volcanic activity | Very Low | 45.9 | $8 | about once every 833 years | 3 |
| Avalanche | Very Low | 44.9 | $303 | about once every 30 years | 1 |
| Inland flooding | Relatively Low | 37.7 | $3.7 million | about once every 7.0 years | 4 |
| Drought | Relatively Low | 35.9 | $37,394 | about 71 a year | 1,792 |
| Winter weather | Relatively Low | 33.2 | $28,578 | about 37 a year | 695 |
| Heat wave | Very Low | 7.5 | $9,252 | about 2.3 a year | 26 |
| Hail | Very Low | 3.4 | $5,617 | about once every 6.0 years | 6.3 |
| Strong wind | Very Low | 2.4 | $9,549 | about once every 9.3 years | 5 |
| Tornado | Very Low | 2.4 | $3,572 | about once every 17 years | 0 |
| Cold wave | No Rating | 0.0 | — | — | 0 |
| Coastal flooding | Not Applicable | — | — | — | — |
| Hurricane | Not Applicable | — | — | — | — |
| Ice storm | Not Applicable | — | — | — | — |
| Tsunami | Not Applicable | — | — | — | — |
Score: FEMA's percentile among US counties that face the hazard (higher = more risk). Expected loss: FEMA's modelled average yearly loss to buildings, people (as a statistical value) and crops. How often: FEMA's annualised frequency of the hazard in the county; for some hazards it counts event-days, so it is a rough guide, not a forecast. "Not Applicable" means FEMA does not model that hazard here.
Federal disaster declarations 14
Most common: Flood 6, Severe Storm 5, Fire 1, Hurricane 1.
| Decade | Declarations | Incident types |
|---|---|---|
| 1960s | 2 | Flood ×2 |
| 1970s | 1 | Drought |
| 1980s | 1 | Flood |
| 1990s | 3 | Severe Storm ×2, Flood |
| 2000s | 2 | Severe Storm, Hurricane |
| 2010s | 2 | Flood, Severe Storm |
| 2020s | 3 | Severe Storm, Flood, Fire |
The last 10
Widest declarations that included Sierra County
- Hurricane Katrina Evacuation (2005, EM-3248-CA): 58 California counties designated.
- Severe Winter Storms, Flooding Landslides, Mud Flow (1995, DR-1046-CA): 57 California counties designated.
- Severe Storms, Flooding, Mud and Landslides (1997, DR-1155-CA): 48 California counties designated.
Named storms in its declarations: Hurricane Katrina (2005).
Not counted above: 2 COVID-19 ("Biological") declarations — in 2020 every US county was included. California also had 30 statewide declarations with no county list.
Tornado record since 1950 0
No tornado in NOAA's Storm Prediction Center record touched Sierra County between 1950 and 2025. That does not mean one cannot happen.
How Sierra County compares with its 5 nearest counties
| County | Distance | Overall risk | Score | Top hazard |
|---|---|---|---|---|
| Sierra County (this page) | — | Very Low | 31.5 | Wildfire |
| Nevada County | 38 km | Relatively Moderate | 89.9 | Wildfire |
| Plumas County | 55 km | Relatively Moderate | 86.4 | Wildfire |
| Placer County | 61 km | Relatively Moderate | 93.1 | Wildfire |
| Yuba County | 80 km | Relatively Low | 80.9 | Drought |
| Carson City, NV | 83 km | Relatively Low | 76.1 | Earthquake |
Nearest by distance between county centres. Every county in California, ranked.
Vulnerability and resilience
| Social vulnerability | Relatively High 63.2 |
|---|---|
| Community resilience | Relatively Low 31.4 |
| Community risk factor | 1.26 |
| Expected annual loss, all hazards | $8.4 million |
FEMA scales expected losses up where social vulnerability is high (people who may find it harder to prepare, evacuate or recover) and down where community resilience is high. A factor above 1 raises the risk score. For social vulnerability a high rating is worse; for resilience a high rating is better.
Prepare for Sierra County's main hazards
- Right now: National Weather Service alerts for California · all official warnings on Global Incident Tracker.
- Wildfire: US wildfires now · Wildfire smoke: what protects you
- Landslide: Landslides recorded
- Lightning: Weather alerts for California
- Your property's flood zone: FEMA Flood Map Service Center ↗ — this page cannot tell you that.
- Official preparedness guidance: Ready.gov ↗ and your county emergency management office.
What this page shows, and what it misses
FEMA's National Risk Index rates a whole county against every other US county; it is a planning-level estimate for nationwide comparison, not a flood-zone map and not a substitute for a local risk assessment or the risk to one home. Declarations are presidential disaster, emergency and fire management declarations that named this county; state declarations and SBA or USDA designations are not included. Tornadoes are counted when the county is one of up to four listed on the track; 670 tornadoes that crossed a state line carry no county list in NOAA's file and are left out.
Federal Emergency Management Agency (FEMA), National Risk Index Dataset: National Risk Index Counties - v1.20.0 (December 2025). Retrieved from https://services.arcgis.com/XG15cJAlne2vxtgt/ArcGIS/rest/services/National_Risk_Index_Counties/FeatureServer/0/query on November 2, 2026, 1:20 PM EST. This product uses the Federal Emergency Management Agency’s National Risk Index dataset API or downloadable datasets 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).
Federal Emergency Management Agency (FEMA), OpenFEMA Dataset: Disaster Declarations Summaries - v2, retrieved from https://www.fema.gov/api/open/v2/DisasterDeclarationsSummaries on November 2, 2026, 1:21 PM EST. 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).
Tornado records: NOAA/NWS Storm Prediction Center, Severe Weather Database, tornadoes 1950–2025 (https://www.spc.noaa.gov/wcm/data/1950-2025_actual_tornadoes.csv, downloaded 2 November 2026). Public domain; not endorsed by NOAA. Compiled by Global Incident Tracker.
Questions about Sierra County
What natural disasters is Sierra County, California most at risk from?
Sierra County, California has a Very Low natural-hazard risk rating in FEMA's National Risk Index (v1.20, December 2025): a score of 31.5 out of 100, higher than about 31% of US counties, with wildfires, landslides and lightning scoring highest of its 18 hazards and $8.4 million a year in expected losses.
How many federal disaster declarations has Sierra County had?
OpenFEMA lists 14 federal disaster declarations that included Sierra County since 1964, not counting 2 for COVID-19; the latest is DR-4699-CA (Severe Winter Storms, Straight-Line Winds, Flooding, Landslides, and Mudslides, declared 3 April 2023). Another 30 California declarations were made statewide without a county list.
How many tornadoes have hit Sierra County?
NOAA's Storm Prediction Center has no tornado on record touching Sierra County from 1950 to 2025.
Is the National Risk Index a flood zone map?
No. The National Risk Index is a planning-level estimate for a whole county, built for nationwide comparison. It does not tell you the flood zone or the risk of a single property: for that, look up the address on FEMA's Flood Map Service Center (msc.fema.gov) and ask your local floodplain manager.