1,729
Recorded events
24
Counties affected
19
Direct deaths
$164.6M
Property damage
Maryland flash flood history: 1,729 recorded events across 24 counties between 1996 and 2025.
Decade by decade
Maryland flash flood history by decade
The 2010s are the busiest decade on record with 792 reported flash flood events across Maryland. 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 Maryland
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | Baltimore County | 314 | 2 | $12.7M | 1996–2025 |
| #2 | Montgomery County | 241 | 1 | $3.4M | 1996–2025 |
| #3 | Harford County | 146 | 2 | $3.9M | 1996–2025 |
| #4 | Prince George's County | 117 | 0 | $4.0M | 1996–2025 |
| #5 | Frederick County | 91 | 6 | $50.7M | 1996–2025 |
| #6 | Howard County | 90 | 3 | $33.2M | 1996–2025 |
| #7 | Anne Arundel County | 85 | 0 | $5.7M | 1996–2025 |
| #8 | St. Mary's County | 72 | 0 | $755K | 1996–2022 |
| #9 | Carroll County | 68 | 1 | $1.8M | 1996–2025 |
| #10 | Allegany County | 61 | 0 | $10.3M | 1996–2025 |
| #11 | Baltimore city | 56 | 4 | $4.9M | 1996–2025 |
| #12 | Cecil County | 56 | 0 | $5.3M | 1996–2025 |
| #13 | Garrett County | 51 | 0 | $3.3M | 1996–2025 |
| #14 | Washington County | 45 | 0 | $7.0M | 1996–2024 |
| #15 | Charles County | 39 | 0 | $340K | 1998–2025 |
| #16 | Queen Anne's County | 32 | 0 | $4.6M | 1998–2021 |
| #17 | Worcester County | 24 | 0 | $0 | 2000–2025 |
| #18 | Dorchester County | 24 | 0 | $1K | 2000–2025 |
| #19 | Calvert County | 23 | 0 | $535K | 1996–2021 |
| #20 | Talbot County | 23 | 0 | $4.1M | 1996–2022 |
| #21 | Wicomico County | 21 | 0 | $50K | 2000–2025 |
| #22 | Kent County | 21 | 0 | $1.0M | 1999–2021 |
| #23 | Caroline County | 19 | 0 | $7.4M | 1996–2018 |
| #24 | Somerset County | 10 | 0 | $0 | 2006–2025 |
Significant events
Deadliest flash flood events in Maryland
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| Jun 27, 2006 | Frederick County | — | 5 | 1 |
| Nov 19, 2003 | Baltimore city | — | 4 | 0 |
| Jun 19, 1996 | Baltimore County | — | 2 | 0 |
| Aug 31, 2018 | Harford County | — | 2 | 0 |
| Jul 31, 2016 | Howard County | — | 2 | 0 |
| May 27, 2018 | Howard County | — | 1 | 0 |
| Sep 1, 2021 | Montgomery County | — | 1 | 3 |
| Jul 31, 2025 | Carroll County | — | 1 | 0 |
| Jun 19, 1996 | Frederick County | — | 1 | 0 |