Riverine Flood Risk in New Hampshire
All New Hampshire counties ranked by FEMA National Risk Index riverine flood score
Riverine Flood risk — rivers and streams overflowing their banks after heavy rain or snowmelt — is rated for 10 of 10 New Hampshire counties in FEMA's National Risk Index. Hillsborough County carries the state's highest riverine flood score at 92.6, with $76M in expected annual riverine flood losses.
No New Hampshire county reaches the High band for riverine flood, and expected annual losses from riverine flood total roughly $314M statewide. The full ranking below links to each county's complete 18-hazard risk profile.
County Rankings — Riverine Flood
| # | County | Riverine Flood Score | Rating | Ann. Freq. | Ann. Loss |
|---|---|---|---|---|---|
| 1 | Hillsborough County | Medium | 1.68 / yr | $76M | |
| 2 | Grafton County | Medium | 4.29 / yr | $43M | |
| 3 | Rockingham County | Medium | 1.21 / yr | $54M | |
| 4 | Merrimack County | Medium | 2.61 / yr | $34M | |
| 5 | Carroll County | Medium | 2.64 / yr | $23M | |
| 6 | Coos County | Medium | 2.39 / yr | $15M | |
| 7 | Strafford County | Medium | 0.71 / yr | $21M | |
| 8 | Cheshire County | Medium | 1.29 / yr | $20M | |
| 9 | Belknap County | Low | 1.04 / yr | $16M | |
| 10 | Sullivan County | Low | 1.36 / yr | $12M |
10 New Hampshire counties with measurable riverine flood risk. See the national riverine flood ranking or all New Hampshire counties by overall risk.
Frequently Asked Questions
Which New Hampshire county has the highest riverine flood risk?
Hillsborough County has the highest FEMA riverine flood risk score in New Hampshire at 92.6 (Medium), with $76M in expected annual losses and about 1.68 events per year.
How many New Hampshire counties face significant riverine flood risk?
10 New Hampshire counties record measurable riverine flood risk in FEMA's National Risk Index; 0 of them are rated High or Very High.