New Hampshire ice storm risk
Hillsborough County has the highest ice storm risk in New Hampshire, scoring 95.4 out of 100 — rated "Very High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Hillsborough County | 95.4 | Very High |
| 2 | Rockingham County | 91.3 | Relatively High |
| 3 | Merrimack County | 89.8 | Relatively High |
| 4 | Strafford County | 88.1 | Relatively High |
| 5 | Carroll County | 86.7 | Relatively High |
| 6 | Belknap County | 83.5 | Relatively High |
| 7 | Cheshire County | 77.8 | Relatively Moderate |
| 8 | Grafton County | 75.8 | Relatively Moderate |
| 9 | Coos County | 69.1 | Relatively Moderate |
| 10 | Sullivan County | 66.7 | Relatively Moderate |
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 New Hampshire:
Frequently asked questions
What is the highest ice storm risk county in New Hampshire?
Hillsborough County, NH has the highest ice storm risk in New Hampshire, with a FEMA National Risk Index score of 95.4 out of 100 (rated "Very High").
How many counties in New Hampshire are rated Very High for ice storm risk?
1 of 10 scored New Hampshire counties are rated "Very High" for ice storm risk by FEMA's National Risk Index.
What causes ice storm risk in New Hampshire?
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.