Flash Flood in New Hampshire
Every flash flood event the National Weather Service has filed in New Hampshire, year by year, with the most significant episodes. Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
The most significant on the map
The most significant flash flood episodes in New Hampshire.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The record
- Events
- 430
- Deaths
- 5
- Injuries
- 6
- Damage
- $93 million
Every year
The most significant
Ranked by deaths, injuries, damage and size together.
- Flash Flood and Flood in New Hampshire, October 8 to 9, 2005A slow-moving cold front interacted with the remnants of Tammy, producing significant rainfall and flooding across southern New Hampshire.
- Flash Flood in New Hampshire, June 27, 1998From 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.
- Flash Flood in New Hampshire, August 7, 2008An area of slow moving showers and thunderstorms produced up to 6 inches of rain in 3 hours resulting in flash flooding on Ames Brook in Ashland which rose rapidly and flooded the Ames Brook Campground.
- Flash Flood and Coastal Flood in New Hampshire, January 13, 2024The second severe storm in a week’s time struck the northern New England coastline during the middle of January.
- Flash Flooding in New Hampshire, July 1, 2017A very strong shortwave and associated cold front were approaching from the west on the morning of July 1st. Ahead of the front, a very warm and moist air mass was in place over New England with values of precipitable water around 2 inches.
- Flash Flood in New Hampshire, July 13, 1996Three 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.
- Flash Flooding in New Hampshire, August 28 to 29, 2011Tropical Storm Irene moved north through central and western New England bringing wind and very heavy rain to New Hampshire.
- Flash Flooding in New Hampshire, July 2, 2013A very warm and humid air mass was in place over the region on the 2nd of July. Precipitable water values approaching 2 inches were common across the forecast area.
- Flash Flood and Flooding in New Hampshire, May 29, 2012A warm front moved through southern New Hampshire early Tuesday morning, leaving the area in a very moist, warm, and unstable airmass. Tuesday afternoon a cold front began moving across western New York and approaching southern New Hampshire.
- Flash Flooding and Flooding in New Hampshire, December 18 to 21, 2023Low pressure began organizing in the Gulf of Mexico on the 16th, setting record low sea level pressures as it traversed the Southeast through the 17th.
- Flash Flooding and Flooding in New Hampshire, July 17 to 19, 2021During the evening of July 17th an area of low pressure slowly moved east along a stationary boundary that stretched from New York to Massachusetts.
- Flash Flooding in New Hampshire, July 29 to 30, 2021A developing area of lower pressure crossed the state on the night of July 29th. Abundant moisture moved into the region ahead of this area of low pressure. Rain began by late afternoon on July 29th across the Connecticut River Valley.
- Flash Flood in New Hampshire, October 20 to 23, 1996A coastal storm which was fed tropical moisture by the circulation around Hurricane Lily produced 8 to 13 inches of rain throughout the County during a 30-hour period. Many homes and businesses were flooded. Roads and bridges were washed out. Several dams were damaged.
- Flash Flood and Hail in New Hampshire, August 6, 2003Slow moving severe thunderstorms brought damaging winds, hail, and flash flooding to Cheshire County. Westmoreland was the hardest hit area, where most of the town's roads were blocked off because of flooding, downed trees, and power lines.
- Flash Flooding in New Hampshire, October 30, 2017Intense low pressure moving north through the Hudson Valley swept up the remains of tropical storm Philippe on the morning of the 30th.
- Flash Flood in New Hampshire, July 11 to 12, 2019Slow moving thunderstorms produced 4 to 7 inches of rain which fell in less than 6 hours, causing serious flash flooding.
- Flash Flooding in New Hampshire, August 7, 2008An area of slow moving showers and thunderstorms produced up to 6 inches of rain in 3 hours resulting in flash flooding in several towns in southeast New Hampshire. Numerous roads were inundated by small streams and many were washed out.
- Flash Flood in New Hampshire, October 20 to 23, 1996A coastal storm which was fed tropical moisture by the circulation around Hurricane Lily produced between 7 and 9 inches of precipitation throughout the County during a 30-hour period. Many homes and businesses were flooded. Roads and bridges were washed out.
- Flash Flood in New Hampshire, October 20 to 23, 1996A coastal storm which was fed tropical moisture by the circulation around Hurricane Lily produced between 8 and 10 inches of rain throughout the County during a 30-hour period. Many homes and businesses were flooded. Roads and bridges were washed out and an area dam was damaged.
- Flash Flooding in New Hampshire, June 13 to 15, 1998Three to eight inches of rain caused small rivers and streams to rise. Many roads were flooded and/or washed out. Campgrounds and some lakeside homes had to be evacuated.
- Flash Flooding and Flood in New Hampshire, May 26 to 27, 2011A stationary front located through northern New Hampshire provided a focus for showers and thunderstorms to develop. Due to the slow movement of the storms rainfall rates were high resulting in flash flooding.
- Flash Flood in New Hampshire, June 9 to 10, 2005A stationary front was located through New Hampshire in an East-West orientation. Thunderstorms fired on the front during the evening hours and remained nearly stationary through Grafton county. Radar indicated 3 to 5+ inches of rain in 3 hours.
- Flash Flooding and Flooding in New Hampshire, September 16 to 18, 1999A southeast flow of tropical moisture developed over New Hampshire late Wednesday, September 15 as Hurricane Floyd moved slowly northeastward along the East Coast of the United States.
- Flash Flood in New Hampshire, October 21, 1996A coastal storm which was fed tropical moisture by the circulation around Hurricane Lily in the Atlantic produced about 5 inches of rain throughout the County during a 30-hour period, causing the Cold River Dam in Lempster to fail which resulted in a flash flood..
- Flash Flood in New Hampshire, October 21 to 22, 1996A coastal storm which was fed tropical moisture by the circulation around Hurricane Lily produced between 3 and 8 inches of rain throughout the County during a 30-hour period. Roads and bridges were washed out.
More
Sources
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24.