Flash Flood Warnings in Montana, 2023

By month

17 of 67 flash flood warnings covering Montana in 2023 had a flash flood report inside them; 18 of 38 flash flood reports fell inside a warning, on average 70 minutes after it went out.

Montana, 2023

Each office's whole area, 2023

An office's figures cover every county it serves, including across state lines.

Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.

• Stillwater County13
• Carbon County9
• Yellowstone County7
• Sweet Grass County6
• Big Horn County5
• Golden Valley County4
• Musselshell County4
• Rosebud County4
• Custer County3
• Fergus County3
• Blaine County3
• Lewis and Clark County3
• Teton County3
• Meagher County3
• Wheatland County2
• Garfield County2
• Valley County2
• Chouteau County2
• Hill County2
• Pondera County2
• Phillips County1
• Sanders County1
• Daniels County1
• Gallatin County1
• Silver Bow County1
• Glacier County1
• Cascade County1
• Liberty County1
• Toole County1
• Treasure County1
• Broadwater County1
• Petroleum County1
• Dawson County1
• Prairie County1

1. June 6, 20238flash flood warnings
2. June 8, 20237flash flood warnings
3. June 23, 20237flash flood warnings
4. June 7, 20236flash flood warnings
5. June 9, 20236flash flood warnings
6. June 24, 20236flash flood warnings
7. June 2, 20233flash flood warnings
8. June 3, 20233flash flood warnings
9. June 10, 20233flash flood warnings
10. June 26, 20233flash flood warnings
11. May 24, 20232flash flood warnings
12. May 25, 20232flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20222024

National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.