4,722
Recorded events
67
Counties affected
73
Direct deaths
$2.0B
Property damage
Pennsylvania flash flood history: 4,722 recorded events across 67 counties between 1996 and 2026.
Decade by decade
Pennsylvania flash flood history by decade
The 2010s are the busiest decade on record with 1,595 reported flash flood events across Pennsylvania. Earlier decades are thinner because systematic reporting for this hazard expanded over time, not because the weather was calmer.
County ranking
Counties with the most flash flood events in Pennsylvania
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | Allegheny County | 497 | 6 | $60.3M | 1996–2026 |
| #2 | Westmoreland County | 238 | 1 | $15.0M | 1996–2025 |
| #3 | Chester County | 223 | 2 | $46.7M | 1996–2025 |
| #4 | Montgomery County | 192 | 9 | $139.7M | 1996–2025 |
| #5 | Berks County | 177 | 2 | $18.9M | 1996–2025 |
| #6 | Bradford County | 159 | 0 | $88.9M | 1996–2025 |
| #7 | Delaware County | 144 | 1 | $55.9M | 1996–2025 |
| #8 | Washington County | 143 | 1 | $5.1M | 1996–2025 |
| #9 | Philadelphia County | 142 | 4 | $124.2M | 1996–2025 |
| #10 | Bucks County | 122 | 12 | $96.0M | 1996–2025 |
| #11 | Fayette County | 119 | 0 | $9.9M | 1996–2025 |
| #12 | Luzerne County | 111 | 3 | $239.4M | 1996–2025 |
| #13 | Lancaster County | 106 | 0 | $5.7M | 1996–2025 |
| #14 | Northampton County | 99 | 0 | $52.5M | 1996–2025 |
| #15 | Susquehanna County | 97 | 1 | $125.9M | 1996–2025 |
| #16 | York County | 96 | 2 | $6.1M | 1996–2025 |
| #17 | Lawrence County | 96 | 0 | $2.3M | 1996–2026 |
| #18 | Lehigh County | 95 | 1 | $35.3M | 1996–2025 |
| #19 | Beaver County | 95 | 0 | $18.9M | 1996–2025 |
| #20 | Lackawanna County | 84 | 2 | $109.9M | 1996–2025 |
| #21 | Mercer County | 82 | 0 | $767K | 1996–2025 |
| #22 | Butler County | 75 | 0 | $6.9M | 1996–2025 |
| #23 | Venango County | 72 | 0 | $52.0M | 1996–2026 |
| #24 | Crawford County | 63 | 1 | $69.2M | 1996–2021 |
| #25 | Monroe County | 63 | 0 | $8.2M | 1996–2025 |
Significant events
Deadliest flash flood events in Pennsylvania
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Jul 15, 2023 | Bucks County | — | 7 | 0 |
| Jan 19, 1996 | Lycoming County | — | 6 | 0 |
| Jan 19, 1996 | Juniata County | — | 4 | 0 |
| Aug 19, 2011 | Allegheny County | — | 4 | 1 |
| Sep 16, 1999 | Montgomery County | — | 3 | 8 |
| Jun 27, 2006 | Luzerne County | — | 3 | 0 |
| May 10, 2004 | York County | — | 2 | 0 |
| Sep 8, 1996 | Montgomery County | — | 2 | 0 |
| Jul 11, 2019 | Berks County | — | 2 | 0 |
| Nov 6, 2017 | Erie County | — | 2 | 0 |