254
Recorded events
3
Counties affected
4
Direct deaths
$31.9M
Property damage
Delaware flash flood history: 254 recorded events across 3 counties between 1996 and 2025.
Decade by decade
Delaware flash flood history by decade
The 2010s are the busiest decade on record with 93 reported flash flood events across Delaware. 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 Delaware
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | New Castle County | 156 | 4 | $27.9M | 1996–2025 |
| #2 | Sussex County | 68 | 0 | $2.9M | 1999–2025 |
| #3 | Kent County | 30 | 0 | $1.1M | 1996–2021 |
Significant events
Deadliest flash flood events in Delaware
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Sep 16, 1999 | New Castle County | — | 2 | 1 |
| Aug 28, 2011 | New Castle County | — | 2 | 0 |