Flash Flood Warnings in Montana, 2018

By month

12 of 23 flash flood warnings covering Montana in 2018 had a flash flood report inside them; 13 of 22 flash flood reports fell inside a warning, on average 70 minutes after it went out.

Montana, 2018

Each office's whole area, 2018

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.

• Blaine County4
• McCone County4
• Cascade County4
• Chouteau County3
• Dawson County3
• Hill County2
• Golden Valley County2
• Wheatland County2
• Richland County2
• Custer County2
• Prairie County2
• Carter County2
• Phillips County1
• Carbon County1
• Stillwater County1
• Garfield County1
• Roosevelt County1
• Lewis and Clark County1
• Toole County1
• Judith Basin County1
• Yellowstone County1

1. May 27, 20184flash flood warnings
2. June 8, 20183flash flood warnings
3. July 17, 20183flash flood warnings
4. May 17, 20182flash flood warnings
5. June 23, 20182flash flood warnings
6. May 21, 20181flash flood warnings
7. May 23, 20181flash flood warnings
8. June 7, 20181flash flood warnings
9. June 10, 20181flash flood warnings
10. June 16, 20181flash flood warnings
11. June 26, 20181flash flood warnings
12. June 29, 20181flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20172019

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.