Tornado Warnings in Montana, 2010

By month

13 of 56 tornado warnings covering Montana in 2010 had a tornado report inside them; 17 of 39 tornado reports fell inside a warning, on average 15 minutes after it went out.

Montana, 2010

Each office's whole area, 2010

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.

• Powder River County12
• Rosebud County9
• Daniels County9
• McCone County7
• Big Horn County7
• Sheridan County7
• Valley County6
• Carter County5
• Roosevelt County5
• Custer County3
• Richland County3
• Yellowstone County3
• Prairie County2
• Dawson County2
• Garfield County1
• Carbon County1
• Phillips County1
• Golden Valley County1
• Sweet Grass County1

1. June 22, 201016tornado warnings
2. June 21, 20106tornado warnings
3. August 12, 20106tornado warnings
4. May 28, 20104tornado warnings
5. June 20, 20104tornado warnings
6. July 27, 20104tornado warnings
7. August 7, 20104tornado warnings
8. May 27, 20102tornado warnings
9. June 16, 20102tornado warnings
10. July 26, 20102tornado warnings
11. July 29, 20102tornado warnings
12. June 15, 20101tornado warnings

Alerts in force nowTornadoes on recordThe radar archive20092011

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.