120
Recorded events
2
Direct deaths
73
Direct injuries
$91.4M
Property damage
Flash Flood in Middlesex County, New Jersey: 120 recorded events between 1996 and 2025. The strongest on record measured 0. That places the county #119 nationally and #5 statewide for this hazard.
Decade by decade
Flash Flood in Middlesex County, New Jersey: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in Middlesex County is the 2020s, when 52 of the county's 120 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 Middlesex County archive, flash flood makes up 19.6% of all recorded severe weather across 9 hazard types. Nationally the county sits at #119 for this hazard and #5 within New Jersey, putting it in the 96.2 percentile of all U.S. counties.
Seasonality
Events by month
Jul is the peak month for flash flood in Middlesex County with 42 recorded events, while Feb 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 |
|---|---|---|---|---|---|
| Sep 1, 2021 | MIDDLESEX | 0 | 2 | 0 | $50.0M |
| Sep 16, 1999 | COUNTYWIDE | 0 | 0 | 72 | $28.0M |
| Oct 19, 1996 | COUNTYWIDE | 0 | 0 | 1 | $2.7M |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jul 31, 2025 | SOUTH AMBOY JCT | 0 | $0 |
| Jul 31, 2025 | SAYREVILLE JCT | 0 | $0 |
| Jul 31, 2025 | HOPELAWN | 0 | $0 |
| Jul 14, 2025 | GILLESPIE | 0 | $0 |
| Jul 14, 2025 | MIDDLESEX | 0 | $0 |
| Jul 14, 2025 | COLONIA | 0 | $0 |
| May 14, 2025 | KEASBEY | 0 | $0 |
| May 14, 2025 | GILLESPIE | 0 | $10K |
| Aug 7, 2024 | SOUTH AMBOY JCT | 0 | $0 |
| Aug 7, 2024 | EAST BRUNSWICK | 0 | $0 |
Other hazards here
More from Middlesex County
- Thunderstorm Wind 273
- Hail 62
- Heavy Rain 61
- Lightning 45
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
Widespread flash flooding occurred in Middlesex County with numerous road closures and over 500 water rescues. A total of three flood related fatalities were reported in the county, one in South Plainfield, one in Piscataway Township, and one in Woodbridge Township. There was significant damage to structures and vehicles, mainly in the northern part of the county. Many waterways overflowed their banks, including the Lawrence Brook.
Thunderstorms with torrential downpours caused poor drainage flash flooding that resulted in several water rescues and stranded vehicles in Woodbridge. Three vehicles were trapped on Woodbridge Center Drive. Several other vehicles were caught in flood waters on U.S. Route 9 under the New Jersey State Route 440 Bridge and also on Leesville Avenue. Doppler Radar storm total estimates were around 3 inches in the Woodbridge area.
Widespread and significant flash flooding occurred in Monroe Township. About 95 houses in the Rossmoor development were impacted by the flood waters, with many of the structures sustaining quite a bit of damage. Numerous roads in the township were closed and many vehicles were stranded in the flood waters. A section of NJ Route 33 to the east of Applegarth Road was closed.
Quick answers
Frequently asked
How many flash flood events are on record in Middlesex County, New Jersey?
120 flash flood events are recorded in Middlesex County between 1996 and 2025, causing 2 direct deaths.
What is the strongest flash flood recorded in Middlesex County?
The strongest flash flood on record in Middlesex County measured 0.
Where does the flash flood data for Middlesex 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 Middlesex County, New Jersey.” Severe Weather History. severeweatherhistory.com/county/new-jersey/middlesex-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.