Hillsborough County
New Hampshire — Natural Disaster Risk Assessment
MediumComposite Risk Score
National percentile: 90th
Hillsborough County faces medium composite natural disaster risk (NRI Risk Index score 89.8, 90th national percentile), driven primarily by ice storm and lightning exposure. Expected annual loss across all 18 hazard types is $120M.
Source: FEMA National Risk Index v1.20 · Updated December 2025
Top Hazards
All 18 Hazard Risks
| Ice Storm | Very High | 2.14 / yr | $3M |
| Lightning | High | 21.14 / yr | $2M |
| Hurricane | Medium | 0.11 / yr | $18M |
| Riverine Flood | Medium | 1.68 / yr | $76M |
| Earthquake | Low | 0.00 / yr | $6M |
| Winter Weather | High | 18.54 / yr | $486K |
| Strong Wind | High | 1.05 / yr | $3M |
| Landslide | Low | 0.96 / yr | $39K |
| Tornado | Medium | 0.16 / yr | $7M |
| Heat Wave | Low | 3.76 / yr | $2M |
| Wildfire | Low | 0.00 / yr | $204K |
| Cold Wave | Medium | 1.72 / yr | $3M |
| Drought | Low | 3.95 / yr | $357K |
| Hail | Low | 2.37 / yr | $473K |
| Avalanche | Very Low | 0.01 / yr | $28 |
| Coastal Flood | Very Low | 0.00 / yr | $0 |
| Tsunami | Very Low | 0.00 / yr | $0 |
| Volcanic Activity | Very Low | 0.00 / yr | $0 |
Frequently Asked Questions
What is the overall natural disaster risk for Hillsborough County?
Hillsborough County has a composite FEMA National Risk Index score of 89.8 out of 100, placing it in the Medium category and the 90th national percentile. This combines Expected Annual Loss, Social Vulnerability, and Community Resilience across 18 hazard types.
What are the top natural hazards in Hillsborough County?
The three highest-rated hazards are Ice Storm (Very High, $3M EAL), Lightning (High, $2M EAL), Hurricane (Medium, $18M EAL). These account for most of the county's expected annual losses.
How does Hillsborough County compare to other New Hampshire counties?
Hillsborough County ranks #1 of 10 New Hampshire counties for overall natural disaster risk, with a medium rating.
What does Expected Annual Loss (EAL) mean?
EAL is FEMA's estimate of average annual dollar losses from natural hazards, calculated from historical event data and exposure models. Hillsborough County's $120M EAL is a statistical average, not a guarantee for any specific year or address.