Idaho cold wave risk
Bonneville County has the highest cold wave risk in Idaho, scoring 93 out of 100 — rated "Relatively High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Bonneville County | 93 | Relatively High |
| 2 | Bannock County | 88.6 | Relatively Moderate |
| 3 | Kootenai County | 88.6 | Relatively Moderate |
| 4 | Madison County | 85.2 | Relatively Moderate |
| 5 | Jefferson County | 81.8 | Relatively Moderate |
| 6 | Bingham County | 81.7 | Relatively Moderate |
| 7 | Power County | 78.5 | Relatively Moderate |
| 8 | Bonner County | 71.6 | Relatively Moderate |
| 9 | Latah County | 53.3 | Relatively Low |
| 10 | Fremont County | 52.5 | Relatively Low |
| 11 | Ada County | 51.7 | Relatively Low |
| 12 | Boundary County | 47.9 | Relatively Low |
| 13 | Minidoka County | 45 | Relatively Low |
| 14 | Blaine County | 44.4 | Relatively Low |
| 15 | Teton County | 43.7 | Relatively Low |
| 16 | Cassia County | 42.7 | Relatively Low |
| 17 | Twin Falls County | 41.2 | Relatively Low |
| 18 | Butte County | 40 | Relatively Low |
| 19 | Shoshone County | 35.7 | Relatively Low |
| 20 | Benewah County | 31.9 | Relatively Low |
| 21 | Lemhi County | 30.7 | Relatively Low |
| 22 | Custer County | 30.4 | Relatively Low |
| 23 | Jerome County | 28.7 | Relatively Low |
| 24 | Caribou County | 28.1 | Relatively Low |
| 25 | Canyon County | 26 | Relatively Low |
| 26 | Lincoln County | 24.2 | Relatively Low |
| 27 | Gooding County | 22.6 | Very Low |
| 28 | Franklin County | 20.5 | Very Low |
| 29 | Nez Perce County | 19.3 | Very Low |
| 30 | Bear Lake County | 18.5 | Very Low |
| 31 | Clark County | 12.9 | Very Low |
| 32 | Elmore County | 12.2 | Very Low |
| 33 | Idaho County | 11.7 | Very Low |
| 34 | Oneida County | 10.1 | Very Low |
| 35 | Owyhee County | 9.8 | Very Low |
| 36 | Clearwater County | 9.6 | Very Low |
| 37 | Lewis County | 9.5 | Very Low |
| 38 | Payette County | 8.3 | Very Low |
| 39 | Washington County | 8 | Very Low |
| 40 | Camas County | 7.5 | Very Low |
| 41 | Gem County | 6.4 | Very Low |
| 42 | Valley County | 5.5 | Very Low |
| 43 | Adams County | 5.4 | Very Low |
| 44 | Boise County | 4.6 | 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.
Cold Wave risk nationally:
Other hazard risks in Idaho:
Frequently asked questions
What is the highest cold wave risk county in Idaho?
Bonneville County, ID has the highest cold wave risk in Idaho, with a FEMA National Risk Index score of 93 out of 100 (rated "Relatively High").
What causes cold wave risk in Idaho?
Cold wave risk captures expected losses from extended periods of extreme cold, including wind chill. The northern Plains, Great Lakes, and interior New England see the most severe and frequent cold events. Cold extremes cause significant excess mortality, especially among unhoused populations, the elderly, and those with inadequate heating or insulation. Cold and wind chill events are reported at forecast-zone level in NOAA Storm Events and are not included in county-level counts.