Idaho tornado risk
Ada County has the highest tornado risk in Idaho, scoring 27 out of 100 — rated "Relatively Low" by FEMA's National Risk Index. Recorded tornado events across Idaho have decreased 33% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Ada County | 27 | Relatively Low | 1 |
| 2 | Kootenai County | 22 | Very Low | 0 |
| 3 | Canyon County | 20.8 | Very Low | 0 |
| 4 | Bonneville County | 16.2 | Very Low | 1 |
| 5 | Bannock County | 15.1 | Very Low | 0 |
| 6 | Twin Falls County | 13.4 | Very Low | 1 |
| 7 | Teton County | 10.6 | Very Low | 0 |
| 8 | Bonner County | 10.3 | Very Low | 0 |
| 9 | Madison County | 9.9 | Very Low | 0 |
| 10 | Cassia County | 9.8 | Very Low | 2 |
| 11 | Gooding County | 9.6 | Very Low | 0 |
| 12 | Latah County | 9.4 | Very Low | 0 |
| 13 | Jerome County | 9 | Very Low | 1 |
| 14 | Minidoka County | 8.3 | Very Low | 0 |
| 15 | Bingham County | 8.2 | Very Low | 4 |
| 16 | Blaine County | 7.7 | Very Low | 0 |
| 17 | Nez Perce County | 7.5 | Very Low | 0 |
| 18 | Elmore County | 7.1 | Very Low | 2 |
| 19 | Jefferson County | 7 | Very Low | 2 |
| 20 | Fremont County | 6.8 | Very Low | 1 |
| 21 | Payette County | 6.7 | Very Low | 0 |
| 22 | Owyhee County | 6.2 | Very Low | 2 |
| 23 | Idaho County | 6.1 | Very Low | 0 |
| 24 | Gem County | 5.9 | Very Low | 0 |
| 25 | Washington County | 5.5 | Very Low | 0 |
| 26 | Power County | 5.3 | Very Low | 0 |
| 27 | Benewah County | 5.1 | Very Low | 0 |
| 28 | Boise County | 4 | Very Low | 0 |
| 29 | Shoshone County | 4 | Very Low | 0 |
| 30 | Lincoln County | 3.9 | Very Low | 0 |
| 31 | Valley County | 3.6 | Very Low | 0 |
| 32 | Boundary County | 3.5 | Very Low | 0 |
| 33 | Clearwater County | 3.4 | Very Low | 0 |
| 34 | Franklin County | 3.2 | Very Low | 0 |
| 35 | Caribou County | 3.1 | Very Low | 2 |
| 36 | Lemhi County | 3.1 | Very Low | 0 |
| 37 | Butte County | 3 | Very Low | 1 |
| 38 | Custer County | 3 | Very Low | 0 |
| 39 | Adams County | 2.9 | Very Low | 0 |
| 40 | Lewis County | 2.8 | Very Low | 0 |
| 41 | Oneida County | 2.6 | Very Low | 0 |
| 42 | Bear Lake County | 2 | Very Low | 0 |
| 43 | Camas County | 1.7 | Very Low | 0 |
| 44 | Clark County | 1.5 | Very Low | 0 |
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.
Tornado risk nationally:
Other hazard risks in Idaho:
Frequently asked questions
What is the highest tornado risk county in Idaho?
Ada County, ID has the highest tornado risk in Idaho, with a FEMA National Risk Index score of 27 out of 100 (rated "Relatively Low").
What causes tornado risk in Idaho?
Tornado risk concentrates in the central and southern plains ("Tornado Alley") and the Southeast ("Dixie Alley"), where atmospheric conditions favor supercell thunderstorm development. The highest scores often belong to counties with significant mobile home and manufactured housing stock, which carries disproportionate tornado mortality risk.