693
Recorded events
56
Counties affected
8
Direct deaths
$72.8M
Property damage
Montana flood history: 693 recorded events across 56 counties between 1996 and 2025.
Decade by decade
Montana flood history by decade
The 2010s are the busiest decade on record with 436 reported flood events across Montana. 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 flood events in Montana
| Rank | County | Events | Deaths | Damage | Span |
|---|---|---|---|---|---|
| #1 | Valley County | 78 | 0 | $1.1M | 1999–2023 |
| #2 | Phillips County | 38 | 0 | $1K | 1997–2023 |
| #3 | Roosevelt County | 22 | 0 | $0 | 1997–2023 |
| #4 | Missoula County | 21 | 0 | $520K | 1996–2023 |
| #5 | Lewis and Clark County | 18 | 0 | $100K | 2008–2023 |
| #6 | Richland County | 17 | 0 | $0 | 2011–2025 |
| #7 | Petroleum County | 17 | 0 | $515K | 2008–2022 |
| #8 | Blaine County | 17 | 0 | $2.1M | 1996–2024 |
| #9 | Dawson County | 17 | 0 | $50K | 2011–2025 |
| #10 | Garfield County | 16 | 0 | $0 | 2008–2023 |
| #11 | Cascade County | 15 | 2 | $60K | 2010–2023 |
| #12 | Ravalli County | 13 | 1 | $108K | 1996–2020 |
| #13 | Yellowstone County | 13 | 1 | $300K | 1997–2025 |
| #14 | Rosebud County | 12 | 0 | $225K | 2011–2019 |
| #15 | Flathead County | 11 | 0 | $35K | 1996–2022 |
| #16 | Big Horn County | 11 | 0 | $4.0M | 2011–2019 |
| #17 | Fergus County | 11 | 0 | $135K | 2002–2023 |
| #18 | Gallatin County | 10 | 0 | $1.0M | 2006–2023 |
| #19 | Custer County | 10 | 0 | $1.2M | 1999–2025 |
| #20 | Madison County | 9 | 0 | $0 | 2009–2020 |
| #21 | Musselshell County | 9 | 0 | $6.0M | 1997–2025 |
| #22 | Wibaux County | 9 | 0 | $0 | 1997–2011 |
| #23 | Daniels County | 9 | 0 | $30K | 1999–2025 |
| #24 | Sheridan County | 9 | 0 | $0 | 1999–2017 |
| #25 | Prairie County | 8 | 0 | $0 | 2011–2023 |
Significant events
Deadliest flood events in Montana
| Date | County | Scale | Deaths | Injuries |
|---|---|---|---|---|
| May 17, 2023 | Cascade County | — | 2 | 0 |
| May 21, 2011 | Yellowstone County | — | 1 | 0 |
| May 20, 2011 | Carbon County | — | 1 | 0 |
| May 17, 1996 | Ravalli County | — | 1 | 0 |