Severe Weather History


Montana Flood History: 693 Recorded Events

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

Montana flood history: recorded events per decade
Montana flood history: recorded events per 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

RankCountyEventsDeathsDamageSpan
#1Valley County780$1.1M1999–2023
#2Phillips County380$1K1997–2023
#3Roosevelt County220$01997–2023
#4Missoula County210$520K1996–2023
#5Lewis and Clark County180$100K2008–2023
#6Richland County170$02011–2025
#7Blaine County170$2.1M1996–2024
#8Petroleum County170$515K2008–2022
#9Dawson County170$50K2011–2025
#10Garfield County160$02008–2023
#11Cascade County152$60K2010–2023
#12Yellowstone County131$300K1997–2025
#13Ravalli County131$108K1996–2020
#14Rosebud County120$225K2011–2019
#15Fergus County110$135K2002–2023
#16Flathead County110$35K1996–2022
#17Big Horn County110$4.0M2011–2019
#18Gallatin County100$1.0M2006–2023
#19Custer County100$1.2M1999–2025
#20Daniels County90$30K1999–2025
#21Sheridan County90$01999–2017
#22Madison County90$02009–2020
#23Musselshell County90$6.0M1997–2025
#24Wibaux County90$01997–2011
#25McCone County80$02011–2019
Source: NOAA/NCEI Storm Events · ranked by recorded event count

Significant events

Deadliest flood events in Montana

DateCountyScaleDeathsInjuries
May 17, 2023Cascade County—20
May 20, 2011Carbon County—10
May 17, 1996Ravalli County—10
May 21, 2011Yellowstone County—10
Source: NOAA/NCEI Storm Events · dates UTC

All hazards in Montana · Flood across the U.S.