New Hampshire floods
Every recorded flood since 1996 · 10 counties with a record
NOAA's Storm Events Database records 1,048 floods and flash floods in New Hampshire from 1996 through June 30, 2026, about 36 a year since 2000. The deadliest was the October 9, 2005 flash flood in Cheshire County: 2 deaths and $15.1 million in damage in 2025 dollars. New Hampshire ranks 40th of 52 states and territories by count and 19th of 51 per square mile.
Floods in New Hampshire, 1996 to 2026
Flood records per year (NOAA Storm Events); 2026 to June 30, 2026.
- recorded, no damage figure
- under $1 million
- $1 million or more
- $10 million or more
- $100 million or more, or 10 deaths
- $1 billion or more, or 100 deaths
- a year's colour: its recorded damage or deaths
- a year with a death
- Records
- 1,0481996 to June 30, 2026
- A year since 2000
- 36average
- Deaths
- 76 injuries
- Damage, 2025 dollars
- $264Mas filed
- Busiest year
- 2023135 records
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; deaths and damage as filed, damage in 2025 dollars. Search the record at NCEI.
Are floods and flash floods common in New Hampshire?
New Hampshire averages about 36 floods and flash floods a year since 2000, 40th of 52 states and territories by count. The busiest year on record was 2023 (135). Per 10,000 square miles of land, New Hampshire records 1170 floods and flash floods since 1996, 19th of 51 states and territories by that measure.
Source: NOAA NCEI Storm Events Database, records since 1996, per 10,000 square miles of land area (Census Bureau 2024 Gazetteer; places under 1,000 square miles not ranked). Damage colours: Storm Events damage, 2025 dollars.
Which counties in New Hampshire have the most floods and flash floods?
Per square mile, Rockingham County leads New Hampshire: 89 days with a flood since 1996, 128.0 per 1,000 square miles of land. By raw count, Grafton County has the most flood records (267 since 1996); large counties collect more records simply by covering more ground, so the ranking counts days with a record per unit of area (a storm filed for several forecast zones adds several records but one day).
Source: NOAA NCEI Storm Events Database, days with a record in the county since 1996 per 1,000 square miles of land (Census Bureau 2024 Gazetteer); in brackets, the count of records.
When is flood season in New Hampshire?
New Hampshire's floods and flash floods by month. The busiest month is July (223 records).
The values, month by month
Jan 52 · Feb 26 · Mar 65 · Apr 153 · May 73 · Jun 90 · Jul 223 · Aug 103 · Sep 37 · Oct 121 · Nov 16 · Dec 89 (records).
Source: NOAA NCEI Storm Events Database, records by the month they began, since 1996.
What were the deadliest floods and flash floods in New Hampshire?
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2005-10-09 | Flash FloodAlstead, Cheshire County A slow-moving cold front interacted with the remnants of Tammy, producing significant rainfall and flooding across southern New Hampshire. Storm total rainfall ranged from between 9 and 11 inches across southwest New Hampshire; and the worst flooding occurred in the Ashuelot River basin, where the community of Alstead ... | 2 | 0 | $15M | |
| 2005-10-08 | FloodSullivan County · forecast zone Sullivan One storm episode: 4 records in 4 places; the totals are the episode's. The interaction between a cold frontal boundary and the remnants of Tropical Storm Tammy resulted in tremendous amount of rainfall throughout most of central and southern New Hampshire. Rainfall ranged from just under 2 inches in far northern New Hampshire to 9 inches at Gilford in Belknap County. An unofficial report ... | 2 | 0 | $6.6M | |
| 2008-08-07 | Flash FloodWest Center Harbor, Belknap County Heavy rain caused flash flooding in Ashland resulting in the death of a young girl and injuring her mother and brother as they tried to drive out of the flood waters in a local campground. Many roads were flooded or washed out in other areas of town. | 1 | 2 | $959K | |
| 1998-06-27 | Flash FloodPiermont, Grafton County From 3 to possibly as much as 6 inches of rain fell in 12 hours causing the Baker River and its tributaries to rise very rapidly. Bridges were destroyed, vehicles were washed away, and some towns were completely isolated as all roads in and out of the towns were flooded. Roads and bridges in much of the area were ... | 1 | 1 | $2.7M | |
| 1996-07-13 | Flash FloodBristol, Grafton County Three to four inches of rain from the remnants of Hurricane Bertha on small rivers and streams. A 10 year old boy playing in the rain-swollen Newfound River was swept to his death. | 1 | 0 | – |
Source: NOAA NCEI Storm Events Database: deaths direct and indirect, as filed by the National Weather Service, summed over each storm (one episode, or one named storm filed by several offices). Storm names from the titles of FEMA declarations that name the storm's counties.
The costliest floods and flash floods in New Hampshire
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2011-08-28 | Tropical Storm Irene · Flash FloodGorham Libby Field Arp, Coos County One named storm filed by several offices: 16 records in 3 episodes; the totals are the storm's. | 0 | 0 | $31M | |
| 2024-01-13 | Coastal FloodRockingham County · forecast zone Coastal Rockingham | 0 | 0 | $28M | |
| 2007-04-16 | Coastal FloodRockingham County · forecast zone Coastal Rockingham One storm episode: 9 records in 8 places; the totals are the episode's. | 0 | 0 | $18M | |
| 2005-10-09 | Flash FloodAlstead, Cheshire County | 2 | 0 | $15M | |
| 2024-01-10 | Coastal FloodRockingham County · forecast zone Coastal Rockingham | 0 | 0 | $14M | |
| 2017-07-01 | Flash FloodHanover Center, Grafton County One storm episode: 5 records; the totals are the episode's. | 0 | 0 | $14M | |
| 2013-07-02 | Flash FloodLebanon, Grafton County One storm episode: 6 records in 2 places; the totals are the episode's. | 0 | 0 | $13M | |
| 2022-12-23 | Coastal FloodRockingham County · forecast zone Coastal Rockingham | 0 | 0 | $10M |
Source: NOAA NCEI Storm Events Database: property and crop damage as estimated by the National Weather Service, in 2025 dollars.
Are floods and flash floods becoming more frequent in New Hampshire?
New Hampshire's count per decade against the whole country's, and its share. NOAA recorded every event type only from 1996, so earlier decades are not comparable; the share of the national total is the fairer comparison across decades.
| Decade | New Hampshire | United States | New Hampshire's share |
|---|---|---|---|
| 1996-99 | 101 | 20,986 | 0.48% |
| 2000s | 251 | 54,913 | 0.46% |
| 2010s | 389 | 68,322 | 0.57% |
| 2020-26 | 307 | 43,563 | 0.70% |
Source: NOAA NCEI Storm Events Database.
The most recent floods and flash floods in New Hampshire
| Date | Record | Character | Killed | Injured | Damage |
|---|---|---|---|---|---|
| 2026-06-11 | FloodEaton Center, Carroll County | 0 | 0 | – | |
| 2026-06-11 | FloodSilver Lake, Carroll County | 0 | 0 | – | |
| 2026-06-11 | FloodMadison, Carroll County | 0 | 0 | – | |
| 2026-06-11 | FloodMadison, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodSilver Lake, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodConway, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodMadison, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodMadison, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodPequaket, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodMadison, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodMadison, Carroll County | 0 | 0 | – | |
| 2026-06-11 | Flash FloodTamworth, Carroll County | 0 | 0 | – |
Source: NOAA NCEI Storm Events Database, records through June 30, 2026; the newest months are revised by NCEI as reports arrive. Search the record at NCEI.
Federal disaster declarations for floods and flash floods in New Hampshire
FEMA has declared 33 disasters in New Hampshire for floods and flash floods, counting its incident type and declarations that name flood in the title (FEMA files most storm disasters under Severe Storm); 32 were major disasters, the latest on August 20, 2024.
| Declared | Number | Title | Areas named |
|---|---|---|---|
| 2024-08-20 | DR-4812 | Severe Storm and Flooding | 2 |
| 2024-07-10 | DR-4799 | Severe Winter Storm and Flooding | 5 |
| 2024-04-19 | DR-4771 | Severe Storms and Flooding | 2 |
| 2024-02-27 | DR-4761 | Severe Storm and Flooding | 3 |
| 2023-09-14 | DR-4740 | Severe Storms and Flooding | 7 |
| 2023-03-15 | DR-4693 | Severe Storm and Flooding | 4 |
| 2021-10-04 | DR-4624 | Severe Storm and Flooding | 2 |
| 2021-09-30 | DR-4622 | Severe Storm and Flooding | 1 |
| 2019-08-15 | DR-4457 | Severe Storm and Flooding | 1 |
| 2018-06-08 | DR-4370 | Severe Storm and Flooding | 1 |
| 2018-01-02 | DR-4355 | Severe Storm and Flooding | 6 |
| 2017-08-09 | DR-4329 | Severe Storms and Flooding | 2 |
Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), through October 2, 2026. OpenFEMA dataset page.
Next
- Rockingham County: the county's whole recordThe New Hampshire county with the most floods and flash floods per square mile
- Floods across the United StatesEvery state ranked, by year and month
- Every natural hazard in New HampshireTornadoes, floods, storms, heat and the federal declarations
- Winter storms in New Hampshire2,612 records
- Severe thunderstorm wind in New Hampshire2,368 records
- Hail in New Hampshire960 records