497
Recorded events
6
Direct deaths
2
Direct injuries
$60.3M
Property damage
Flash Flood in Allegheny County, Pennsylvania: 497 recorded events between 1996 and 2026. The strongest on record measured 0. That places the county #5 nationally and #1 statewide for this hazard.
Decade by decade
Flash Flood in Allegheny County, Pennsylvania: events per decade
Reporting practice changed over time — early decades are undercounted, not calmer.
The busiest decade for flash flood in Allegheny County is the 2010s, when 253 of the county's 497 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 Allegheny County archive, flash flood makes up 21.1% of all recorded severe weather across 8 hazard types. Nationally the county sits at #5 for this hazard and #1 within Pennsylvania, putting it in the 99.9 percentile of all U.S. counties.
Seasonality
Events by month
Jul is the peak month for flash flood in Allegheny County with 167 recorded events, while Jan 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 19, 2011 | SHARPSBURG | 0 | 4 | 1 | $500K |
| Jul 1, 1997 | PITCAIRN | 0 | 1 | 0 | $10.0M |
| Jun 20, 1996 | LEETSDALE | 0 | 1 | 0 | $0 |
| Jun 21, 2018 | BOYCE | 0 | 0 | 1 | $10.0M |
Most recent
Latest recorded events
| Date | Location | Magnitude | Damage |
|---|---|---|---|
| Mar 26, 2026 | OPTION | — | $0 |
| Jul 17, 2025 | CLAIRTON | 0 | $0 |
| Jul 17, 2025 | TARENTUM | 0 | $0 |
| Jul 16, 2025 | BAKERSTOWN | 0 | $0 |
| Jul 16, 2025 | (AGC)ALLEGHENY CO AR | 0 | $0 |
| Jul 16, 2025 | WHITAKER | 0 | $0 |
| Jul 14, 2025 | NORTH BRADDOCK | 0 | $0 |
| Jul 1, 2025 | GLENDALE | 0 | $0 |
| Jul 1, 2025 | MC KEES ROCKS | 0 | $0 |
| Jul 1, 2025 | SHARPSBURG | 0 | $0 |
Other hazards here
More from Allegheny County
- Thunderstorm Wind 1,248
- Hail 444
- Flood 99
From the record
What the reports say
Written by National Weather Service staff at the time of the event · public domain
A NWS storm survey found that 2.5 inches of rain fell in one hour in a very urbanized 4.8 sq mi watershed just east of downtown Pittsburgh. Severe flash flooding developed on Washington Blvd resulting in four fatalities and up to 15 water rescues. A mother and two daughters were drowned inside a van when it became submerged in approximately 9 ��� 10 feet of water. An elderly lady who abandoned her car was apparently swept or fell into an open manhole or catch basin and drowned.
Heavy rain caused flash flooding in the Millvale area and much of the North Hills area of Pittsburgh as Girtys Run came out of it's banks. Over 900 homes were affected by the flooding as well as over 200 businesses. Infrasturcture owned by local municipalities sustained over 4 million dollars in damage.
The 911 Call Center has reported that a number of roads in southern Bethel Park have been flooded and/or impassable. This roads include: Glendale Drive, Logan Road, O'Neill Drive, Dashwood Drive (vehicle was stuck in water). Water entered the Trolley Stop Inn restaurant, cars in the parking lot were submerged (some floating); customers had to be rescued from the building. Local newspaper reports say at least 400 homes have been damaged and two homes were damaged so severely that they became uninhabitable. There was 1 direct injury; a young man was sucked into a storm drain while helping others trapped in the flood. He received a few bruises for this incident.
Quick answers
Frequently asked
How many flash flood events are on record in Allegheny County, Pennsylvania?
497 flash flood events are recorded in Allegheny County between 1996 and 2026, causing 6 direct deaths.
What is the strongest flash flood recorded in Allegheny County?
The strongest flash flood on record in Allegheny County measured 0.
Where does the flash flood data for Allegheny 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 Allegheny County, Pennsylvania.” Severe Weather History. severeweatherhistory.com/county/pennsylvania/allegheny-county/flash-flood/ · Data: NOAA/NCEI, FEMA, U.S. Census — public domain.