California avalanche risk
Placer County has the highest avalanche risk in California, scoring 97.8 out of 100 — rated "Very High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Placer County | 97.8 | Very High |
| 2 | Inyo County | 96.5 | Very High |
| 3 | Los Angeles County | 92.4 | Relatively High |
| 4 | Amador County | 91.7 | Relatively High |
| 5 | Alpine County | 91.1 | Relatively High |
| 6 | Tulare County | 89.9 | Relatively High |
| 7 | Nevada County | 89.5 | Relatively High |
| 8 | Lake County | 89.3 | Relatively High |
| 9 | Mono County | 86.4 | Relatively High |
| 10 | El Dorado County | 85.8 | Relatively High |
| 11 | Siskiyou County | 83.2 | Relatively Moderate |
| 12 | San Bernardino County | 78.5 | Relatively Low |
| 13 | Tuolumne County | 58.9 | Very Low |
| 14 | Trinity County | 54.8 | Very Low |
| 15 | Fresno County | 54.5 | Very Low |
| 16 | Riverside County | 51.6 | Very Low |
| 17 | Humboldt County | 47.2 | Very Low |
| 18 | Kern County | 46.8 | Very Low |
| 19 | Sierra County | 44.9 | Very Low |
| 20 | Plumas County | 43.4 | Very Low |
| 21 | Shasta County | 40.9 | Very Low |
| 22 | Mariposa County | 40.5 | Very Low |
| 23 | Del Norte County | 40.1 | Very Low |
| 24 | Calaveras County | 35.1 | Very Low |
| 25 | Madera County | 34.5 | Very Low |
| 26 | Ventura County | 33.9 | Very Low |
| 27 | San Diego County | 32.2 | Very Low |
| 28 | Mendocino County | 31.7 | Very Low |
| 29 | Monterey County | 30.8 | Very Low |
| 30 | Santa Barbara County | 30.7 | Very Low |
| 31 | Modoc County | 30.6 | Very Low |
| 32 | Tehama County | 28.2 | Very Low |
| 33 | Butte County | 27.8 | Very Low |
| 34 | Lassen County | 26.3 | Very Low |
| 35 | Yuba County | 22.7 | Very Low |
| 36 | Glenn County | 14.9 | Very Low |
| 37 | Orange County | 13.7 | Very Low |
| 38 | Santa Clara County | 13 | Very Low |
| 39 | Sonoma County | 10.8 | Very Low |
| 40 | Colusa County | 9.4 | Very Low |
| 41 | Napa County | 9.2 | Very Low |
| 42 | San Benito County | 8.2 | Very Low |
| 43 | Yolo County | 7.5 | Very Low |
| 44 | Alameda County | 6.6 | Very Low |
| 45 | Stanislaus County | 5.7 | Very Low |
| 46 | San Luis Obispo County | 5.4 | Very Low |
| 47 | Contra Costa County | 5.3 | Very Low |
| 48 | Merced County | 3.4 | Very Low |
| 49 | Santa Cruz County | 3.1 | Very Low |
| 50 | San Joaquin County | 2.2 | Very Low |
| 51 | Solano County | 1.5 | Very Low |
| 52 | Kings County | 0.1 | Very Low |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Avalanche risk nationally:
Other hazard risks in California:
Frequently asked questions
What is the highest avalanche risk county in California?
Placer County, CA has the highest avalanche risk in California, with a FEMA National Risk Index score of 97.8 out of 100 (rated "Very High").
How many counties in California are rated Very High for avalanche risk?
2 of 52 scored California counties are rated "Very High" for avalanche risk by FEMA's National Risk Index.
What causes avalanche risk in California?
Avalanche risk reflects expected annual losses from snow avalanche events, primarily affecting mountain counties in the West. The highest scores belong to Colorado, Utah, Montana, and Washington counties where active ski terrain, mountain highways, and communities overlap with historically active avalanche paths and high seasonal snowpack. Avalanche events are reported at forecast-zone level in NOAA Storm Events and are not included in county-level counts.