Idaho avalanche risk
Blaine County has the highest avalanche risk in Idaho, scoring 96.9 out of 100 — rated "Very High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Blaine County | 96.9 | Very High |
| 2 | Custer County | 96.8 | Very High |
| 3 | Shoshone County | 96.1 | Very High |
| 4 | Bonner County | 94.6 | Relatively High |
| 5 | Bonneville County | 94.2 | Relatively High |
| 6 | Camas County | 92.8 | Relatively High |
| 7 | Teton County | 90.9 | Relatively High |
| 8 | Elmore County | 90.8 | Relatively High |
| 9 | Fremont County | 90.6 | Relatively High |
| 10 | Boise County | 87.6 | Relatively High |
| 11 | Idaho County | 86.1 | Relatively High |
| 12 | Adams County | 86 | Relatively High |
| 13 | Bear Lake County | 84.9 | Relatively Moderate |
| 14 | Valley County | 84.2 | Relatively Moderate |
| 15 | Clearwater County | 82.9 | Relatively Moderate |
| 16 | Boundary County | 82.6 | Relatively Moderate |
| 17 | Butte County | 81.3 | Relatively Moderate |
| 18 | Caribou County | 80 | Relatively Moderate |
| 19 | Clark County | 79.4 | Relatively Moderate |
| 20 | Madison County | 73.7 | Relatively Low |
| 21 | Washington County | 73.5 | Relatively Low |
| 22 | Owyhee County | 71.8 | Relatively Low |
| 23 | Nez Perce County | 66.1 | Very Low |
| 24 | Lewis County | 62.7 | Very Low |
| 25 | Lemhi County | 60.1 | Very Low |
| 26 | Latah County | 59.4 | Very Low |
| 27 | Cassia County | 56.9 | Very Low |
| 28 | Twin Falls County | 54.1 | Very Low |
| 29 | Kootenai County | 53.5 | Very Low |
| 30 | Gem County | 49.9 | Very Low |
| 31 | Benewah County | 48.2 | Very Low |
| 32 | Jerome County | 34.9 | Very Low |
| 33 | Ada County | 27 | Very Low |
| 34 | Franklin County | 25.4 | Very Low |
| 35 | Bannock County | 23 | Very Low |
| 36 | Bingham County | 20.5 | Very Low |
| 37 | Power County | 18.3 | Very Low |
| 38 | Oneida County | 18 | Very Low |
| 39 | Gooding County | 12.3 | Very Low |
| 40 | Payette County | 8 | Very Low |
| 41 | Canyon County | 5.6 | Very Low |
| 42 | Jefferson County | 1.9 | 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 Idaho:
Frequently asked questions
What is the highest avalanche risk county in Idaho?
Blaine County, ID has the highest avalanche risk in Idaho, with a FEMA National Risk Index score of 96.9 out of 100 (rated "Very High").
How many counties in Idaho are rated Very High for avalanche risk?
3 of 42 scored Idaho counties are rated "Very High" for avalanche risk by FEMA's National Risk Index.
What causes avalanche risk in Idaho?
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.