133
Recorded events
3
Direct deaths
0
Direct injuries
$3.5M
Property damage
Flash Flood in New Haven County, Connecticut: 133 recorded events between 1996 and 2025. The strongest on record measured 0. That places the county #99 nationally and #2 statewide for this hazard.
Decade by decade
Flash Flood in New Haven County, Connecticut: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in New Haven County is the 2020s, when 47 of the county's 133 recorded events were logged. Comparing decades is useful for spotting active periods, but the earliest years are thin because systematic reporting for this hazard began later.
Within the New Haven County archive, flash flood makes up 20.7% of all recorded severe weather across 10 hazard types. Nationally the county sits at #99 for this hazard and #2 within Connecticut, putting it in the 96.9 percentile of all U.S. counties.
Seasonality
Events by month
Aug is the peak month for flash flood in New Haven County with 42 recorded events, while Nov is the quietest. Seasonality here is a property of the archive as much as the climate: reports cluster where population and spotter networks are densest.
Significant events
Deadliest on record
| Date | Location | Scale | Deaths | Injuries | Damage |
|---|---|---|---|---|---|
| Aug 18, 2024 | OXFORD | 0 | 2 | 0 | $0 |
| Sep 16, 1999 | COUNTYWIDE | 0 | 1 | 0 | $0 |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Aug 13, 2025 | MIDDLEBURY | 0 | $0 |
| Jul 14, 2025 | WATERBURY | 0 | $0 |
| Aug 18, 2024 | ANSONIA | 0 | $0 |
| Aug 18, 2024 | SEYMOUR | 0 | $0 |
| Aug 18, 2024 | NAUGATUCK | 0 | $0 |
| Aug 18, 2024 | QUAKER FARMS | 0 | $0 |
| Aug 18, 2024 | OXFORD | 0 | $0 |
| Aug 18, 2024 | SEYMOUR | 0 | $0 |
| Aug 18, 2024 | QUAKER FARMS | 0 | $200K |
| Aug 18, 2024 | LAKESIDE | 0 | $0 |
Other hazards here
More from New Haven County
- Thunderstorm Wind 339
- Hail 66
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
The Quinnipiac River at Wallingford rose above its minor flood stage of 10.0 feet at 3:15am EDT September 2nd. The river ultimately crested at a height of 11.25 feet at 6:15am EDT and 7:45am EDT before falling back below flood stage by 9:00am EDT.
Numerous roads were closed due to flooding around the town of Orange including Route 34 (Derby Avenue) at Route 114, Glenbrook Road, Mapledale Road, Chestnut Ridge Road, Edison Road, Grassy Hill Road, Opekun Road, and Arrowhead Road.
Humphrey St. near James St. as well as Brewery St. in New Haven were closed due to flooding. Several cars were stranded in flood waters. Route 34 eastbound was also closed at Interstates 91 and 95 due to flash flooding.
Quick answers
Frequently asked
How many flash flood events are on record in New Haven County, Connecticut?
133 flash flood events are recorded in New Haven County between 1996 and 2025, causing 3 direct deaths.
What is the strongest flash flood recorded in New Haven County?
The strongest flash flood on record in New Haven County measured 0.
Where does the flash flood data for New Haven County come from?
All events come from the NOAA/NCEI Storm Events Database, the federal public-domain archive of severe weather reports. Dates are UTC, damage is as reported and not inflation-adjusted, and the most recent entries may still be revised.
Cite this page
“Flash Flood in New Haven County, Connecticut.” Severe Weather History. severeweatherhistory.com/county/connecticut/new-haven-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.