Montana ice storm risk
Missoula County has the highest ice storm risk in Montana, scoring 89.9 out of 100 — rated "Relatively High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Missoula County | 89.9 | Relatively High |
| 2 | Sanders County | 78.8 | Relatively Moderate |
| 3 | Ravalli County | 76.8 | Relatively Moderate |
| 4 | Lake County | 72.7 | Relatively Moderate |
| 5 | Flathead County | 69.5 | Relatively Moderate |
| 6 | Sheridan County | 46.7 | Relatively Low |
| 7 | Richland County | 43.6 | Relatively Low |
| 8 | Lincoln County | 41.6 | Relatively Low |
| 9 | Roosevelt County | 40.2 | Relatively Low |
| 10 | Mineral County | 38.5 | Relatively Low |
| 11 | Yellowstone County | 34.2 | Relatively Low |
| 12 | Granite County | 29.1 | Relatively Low |
| 13 | Gallatin County | 24.1 | Very Low |
| 14 | Cascade County | 23.9 | Very Low |
| 15 | Wibaux County | 22.4 | Very Low |
| 16 | Fallon County | 18.6 | Very Low |
| 17 | Lewis and Clark County | 15.7 | Very Low |
| 18 | Deer Lodge County | 14.2 | Very Low |
| 19 | Silver Bow County | 13.5 | Very Low |
| 20 | Hill County | 12.9 | Very Low |
| 21 | Powell County | 12.9 | Very Low |
| 22 | Big Horn County | 12.5 | Very Low |
| 23 | Dawson County | 11.8 | Very Low |
| 24 | Fergus County | 11.4 | Very Low |
| 25 | Park County | 11.2 | Very Low |
| 26 | Glacier County | 10.7 | Very Low |
| 27 | Carbon County | 10.4 | Very Low |
| 28 | Chouteau County | 10.4 | Very Low |
| 29 | Rosebud County | 10.3 | Very Low |
| 30 | Custer County | 10 | Very Low |
| 31 | Beaverhead County | 9.9 | Very Low |
| 32 | Blaine County | 8.5 | Very Low |
| 33 | Valley County | 8.4 | Very Low |
| 34 | Madison County | 7.5 | Very Low |
| 35 | Phillips County | 7.4 | Very Low |
| 36 | Jefferson County | 7 | Very Low |
| 37 | Toole County | 6.4 | Very Low |
| 38 | Carter County | 5.9 | Very Low |
| 39 | Musselshell County | 5.7 | Very Low |
| 40 | Stillwater County | 5.4 | Very Low |
| 41 | Broadwater County | 5.2 | Very Low |
| 42 | Pondera County | 4.7 | Very Low |
| 43 | Judith Basin County | 4.1 | Very Low |
| 44 | Sweet Grass County | 4 | Very Low |
| 45 | Liberty County | 3.7 | Very Low |
| 46 | Daniels County | 3.6 | Very Low |
| 47 | McCone County | 3.6 | Very Low |
| 48 | Wheatland County | 3.3 | Very Low |
| 49 | Teton County | 3 | Very Low |
| 50 | Meagher County | 2.7 | Very Low |
| 51 | Powder River County | 2.6 | Very Low |
| 52 | Prairie County | 2.3 | Very Low |
| 53 | Garfield County | 2.2 | Very Low |
| 54 | Golden Valley County | 1.5 | Very Low |
| 55 | Petroleum County | 0.5 | Very Low |
| 56 | Treasure County | 0.5 | 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.
Ice Storm risk nationally:
Other hazard risks in Montana:
Frequently asked questions
What is the highest ice storm risk county in Montana?
Missoula County, MT has the highest ice storm risk in Montana, with a FEMA National Risk Index score of 89.9 out of 100 (rated "Relatively High").
What causes ice storm risk in Montana?
Ice storm risk covers damaging freezing rain and sleet accumulation, which collapses power lines, trees, and structures. The highest-risk counties cluster in a band from eastern Texas and Arkansas through the Carolinas and New England, where warm Gulf moisture overruns cold arctic air most frequently. Ice storms cause catastrophic and long-lasting power outages. Ice storm and sleet events are reported at forecast-zone level in NOAA Storm Events and are not included in county-level counts.