Montana tornado risk
Roosevelt County has the highest tornado risk in Montana, scoring 32.1 out of 100 — rated "Relatively Low" by FEMA's National Risk Index. Recorded tornado events across Montana have decreased 42% over the past five years compared to the prior five-year period.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | Roosevelt County | 32.1 | Relatively Low | 0 |
| 2 | Yellowstone County | 28.9 | Relatively Low | 1 |
| 3 | Richland County | 27 | Relatively Low | 0 |
| 4 | Dawson County | 25.1 | Very Low | 1 |
| 5 | Cascade County | 20.8 | Very Low | 0 |
| 6 | Carbon County | 17.1 | Very Low | 0 |
| 7 | Gallatin County | 16.7 | Very Low | 0 |
| 8 | Custer County | 16.2 | Very Low | 0 |
| 9 | Sheridan County | 16.1 | Very Low | 3 |
| 10 | Fergus County | 15.7 | Very Low | 0 |
| 11 | Valley County | 14.6 | Very Low | 6 |
| 12 | Big Horn County | 12.1 | Very Low | 1 |
| 13 | Chouteau County | 11.9 | Very Low | 1 |
| 14 | McCone County | 10.8 | Very Low | 0 |
| 15 | Fallon County | 10.5 | Very Low | 3 |
| 16 | Missoula County | 10.1 | Very Low | 0 |
| 17 | Rosebud County | 10.1 | Very Low | 0 |
| 18 | Silver Bow County | 9.8 | Very Low | 0 |
| 19 | Ravalli County | 9.1 | Very Low | 0 |
| 20 | Lewis and Clark County | 8.9 | Very Low | 0 |
| 21 | Prairie County | 8.7 | Very Low | 0 |
| 22 | Wibaux County | 8.7 | Very Low | 0 |
| 23 | Hill County | 8.3 | Very Low | 1 |
| 24 | Park County | 8.3 | Very Low | 0 |
| 25 | Musselshell County | 8.1 | Very Low | 0 |
| 26 | Daniels County | 7.9 | Very Low | 1 |
| 27 | Phillips County | 7.8 | Very Low | 2 |
| 28 | Carter County | 7.6 | Very Low | 5 |
| 29 | Judith Basin County | 7.3 | Very Low | 3 |
| 30 | Powder River County | 7.3 | Very Low | 0 |
| 31 | Beaverhead County | 6.8 | Very Low | 3 |
| 32 | Blaine County | 6.7 | Very Low | 2 |
| 33 | Stillwater County | 6.6 | Very Low | 0 |
| 34 | Lincoln County | 6 | Very Low | 0 |
| 35 | Wheatland County | 5.8 | Very Low | 1 |
| 36 | Jefferson County | 5.7 | Very Low | 1 |
| 37 | Deer Lodge County | 5.5 | Very Low | 0 |
| 38 | Meagher County | 5.2 | Very Low | 0 |
| 39 | Broadwater County | 5.1 | Very Low | 0 |
| 40 | Teton County | 5 | Very Low | 0 |
| 41 | Sanders County | 4.7 | Very Low | 0 |
| 42 | Flathead County | 4.6 | Very Low | 0 |
| 43 | Pondera County | 4.5 | Very Low | 0 |
| 44 | Garfield County | 4.2 | Very Low | 0 |
| 45 | Madison County | 4.1 | Very Low | 0 |
| 46 | Golden Valley County | 3.8 | Very Low | 0 |
| 47 | Sweet Grass County | 3.8 | Very Low | 0 |
| 48 | Toole County | 3.8 | Very Low | 0 |
| 49 | Glacier County | 3.7 | Very Low | 0 |
| 50 | Liberty County | 3.5 | Very Low | 0 |
| 51 | Lake County | 3.3 | Very Low | 1 |
| 52 | Granite County | 2.7 | Very Low | 0 |
| 53 | Petroleum County | 2.5 | Very Low | 2 |
| 54 | Powell County | 2.2 | Very Low | 0 |
| 55 | Treasure County | 1.9 | Very Low | 0 |
| 56 | Mineral County | 1.3 | 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 Montana:
Frequently asked questions
What is the highest tornado risk county in Montana?
Roosevelt County, MT has the highest tornado risk in Montana, with a FEMA National Risk Index score of 32.1 out of 100 (rated "Relatively Low").
What causes tornado risk in Montana?
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.