1,838
Recorded events
21
Counties affected
38
Direct deaths
$1.2B
Property damage
New Jersey flash flood history: 1,838 recorded events across 21 counties between 1996 and 2025.
Decade by decade
New Jersey flash flood history by decade
The 2010s are the busiest decade on record with 669 reported flash flood events across New Jersey. 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 New Jersey
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | Bergen County | 269 | 3 | $17.5M | 1996–2025 |
| #2 | Union County | 140 | 7 | $8.5M | 1996–2025 |
| #3 | Passaic County | 135 | 5 | $9.2M | 1996–2025 |
| #4 | Essex County | 135 | 4 | $15.3M | 1996–2025 |
| #5 | Middlesex County | 120 | 2 | $91.4M | 1996–2025 |
| #6 | Hudson County | 114 | 1 | $400K | 1996–2025 |
| #7 | Camden County | 92 | 0 | $12.9M | 1996–2025 |
| #8 | Monmouth County | 91 | 0 | $19.6M | 1996–2025 |
| #9 | Somerset County | 88 | 7 | $489.2M | 1996–2025 |
| #10 | Burlington County | 87 | 0 | $57.1M | 1996–2025 |
| #11 | Mercer County | 74 | 2 | $93.3M | 1996–2024 |
| #12 | Ocean County | 74 | 0 | $7.1M | 1996–2025 |
| #13 | Gloucester County | 74 | 0 | $5.2M | 1996–2023 |
| #14 | Hunterdon County | 72 | 6 | $20.1M | 1996–2023 |
| #15 | Morris County | 63 | 0 | $53.2M | 1996–2025 |
| #16 | Warren County | 56 | 0 | $7.2M | 1996–2025 |
| #17 | Atlantic County | 40 | 0 | $54.1M | 1997–2025 |
| #18 | Cumberland County | 31 | 0 | $22.4M | 1996–2020 |
| #19 | Sussex County | 30 | 0 | $169.4M | 1996–2023 |
| #20 | Salem County | 30 | 1 | $10.6M | 1996–2025 |
| #21 | Cape May County | 23 | 0 | $650K | 1997–2025 |
Significant events
Deadliest flash flood events in New Jersey
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Sep 1, 2021 | Hunterdon County | — | 6 | 0 |
| Sep 2, 2021 | Union County | — | 4 | 0 |
| Sep 1, 2021 | Somerset County | — | 3 | 0 |
| Sep 1, 2021 | Mercer County | — | 2 | 0 |
| Sep 16, 1999 | Somerset County | — | 2 | 100 |
| Sep 16, 1999 | Bergen County | — | 2 | 0 |
| Sep 1, 2021 | Middlesex County | — | 2 | 0 |
| Sep 1, 2021 | Somerset County | — | 2 | 0 |
| Sep 2, 2021 | Essex County | — | 2 | 0 |
| Jul 15, 2025 | Union County | — | 2 | 0 |