Flash Flood Warnings in New Hampshire, 2023

By month

31 of 59 flash flood warnings covering New Hampshire in 2023 had a flash flood report inside them; 58 of 74 flash flood reports fell inside a warning, on average 103 minutes after it went out.

New Hampshire, 2023

Each office's whole area, 2023

An office's figures cover every county it serves, including across state lines.

Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.

• Grafton County17
• Carroll County16
• Cheshire County15
• Hillsborough County13
• Coos County13
• Merrimack County12
• Rockingham County10
• Belknap County10
• Sullivan County9
• Strafford County7

1. July 16, 20239flash flood warnings
2. July 4, 20238flash flood warnings
3. July 9, 20235flash flood warnings
4. July 29, 20234flash flood warnings
5. June 26, 20233flash flood warnings
6. June 28, 20233flash flood warnings
7. September 8, 20233flash flood warnings
8. June 17, 20232flash flood warnings
9. June 27, 20232flash flood warnings
10. July 18, 20232flash flood warnings
11. July 19, 20232flash flood warnings
12. September 11, 20232flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20222024

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.