New Hampshire avalanche risk
Coos County has the highest avalanche risk in New Hampshire, scoring 97.5 out of 100 — rated "Very High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Coos County | 97.5 | Very High |
| 2 | Grafton County | 74.1 | Relatively Low |
| 3 | Carroll County | 67.7 | Relatively Low |
| 4 | Cheshire County | 37.4 | Very Low |
| 5 | Merrimack County | 28.5 | Very Low |
| 6 | Sullivan County | 24.9 | Very Low |
| 7 | Belknap County | 16.4 | Very Low |
| 8 | Hillsborough County | 15.2 | Very Low |
| 9 | Rockingham County | 4.4 | 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 New Hampshire:
Frequently asked questions
What is the highest avalanche risk county in New Hampshire?
Coos County, NH has the highest avalanche risk in New Hampshire, with a FEMA National Risk Index score of 97.5 out of 100 (rated "Very High").
How many counties in New Hampshire are rated Very High for avalanche risk?
1 of 9 scored New Hampshire counties are rated "Very High" for avalanche risk by FEMA's National Risk Index.
What causes avalanche risk in New Hampshire?
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.