223
Recorded events
2
Direct deaths
1
Direct injuries
$46.7M
Property damage
Flash Flood in Chester County, Pennsylvania: 223 recorded events between 1996 and 2025. The strongest on record measured 0. That places the county #32 nationally and #3 statewide for this hazard.
Decade by decade
Flash Flood in Chester County, Pennsylvania: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in Chester County is the 2020s, when 102 of the county's 223 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 Chester County archive, flash flood makes up 17.4% of all recorded severe weather across 9 hazard types. Nationally the county sits at #32 for this hazard and #3 within Pennsylvania, putting it in the 99.0 percentile of all U.S. counties.
Seasonality
Events by month
Jul is the peak month for flash flood in Chester County with 71 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 16, 1999 | COUNTYWIDE | 0 | 1 | 1 | $3.0M |
| Sep 1, 2021 | NOTTINGHAM | 0 | 1 | 0 | $40.0M |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Jul 10, 2025 | CHESTER SPGS | 0 | $0 |
| Jul 10, 2025 | RED LION | 0 | $0 |
| Jul 10, 2025 | NEW GARDEN | 0 | $5K |
| Jul 10, 2025 | AVONDALE | 0 | $0 |
| Jul 9, 2025 | FIVE PTS | 0 | $5K |
| Jul 9, 2025 | DOWNINGTOWN MEML ARP | 0 | $0 |
| Jul 9, 2025 | STRICKERSVILLE | 0 | $0 |
| Jul 9, 2025 | THORNDALE | 0 | $0 |
| Jul 9, 2025 | WEST GROVE | 0 | $0 |
| Jul 9, 2025 | ROCK RUN | 0 | $20K |
Other hazards here
More from Chester County
- Thunderstorm Wind 769
- Hail 101
- Flood 67
- Lightning 46
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 Chester County with many road closures and vehicles stranded. There was a flood related fatality in Downingtown. Numerous waterways in the county flooded, including the Schuylkill River, the West Branch of the Brandywine Creek, the East Branch of the Brandywine Creek, White Clay Creek, Red Clay Creek, French Creek and Valley Creek. There were many reports of water entering buildings and homes.
Widespread roadway flooding occurred in West Whiteland Township with many roads becoming impassable. Numerous vehicles were trapped in flood waters, with some motorists needing assistance on Spackmans Lane and on Whitford Road.
East Barnard Street in West Chester was closed between South Matlack Street and South Franklin Street due to flooding. South Adams Street in West Chester was closed between East Market Street and East Miner Street due to flooding.
Quick answers
Frequently asked
How many flash flood events are on record in Chester County, Pennsylvania?
223 flash flood events are recorded in Chester County between 1996 and 2025, causing 2 direct deaths.
What is the strongest flash flood recorded in Chester County?
The strongest flash flood on record in Chester County measured 0.
Where does the flash flood data for Chester 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 Chester County, Pennsylvania.” Severe Weather History. severeweatherhistory.com/county/pennsylvania/chester-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.