Flash Flood Warnings in Wisconsin, 2009

By month

23 of 35 flash flood warnings covering Wisconsin in 2009 had a flash flood report inside them; 55 of 67 flash flood reports fell inside a warning, on average 91 minutes after it went out.

Wisconsin, 2009

Each office's whole area, 2009

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.

• Grant County5
• Lafayette County5
• Crawford County4
• Rock County4
• Green County4
• Milwaukee County3
• Waukesha County3
• Racine County3
• Walworth County3
• Buffalo County3
• Trempealeau County3
• Dunn County3
• Pepin County3
• Pierce County3
• Iowa County2
• Sauk County2
• Richland County2
• Jefferson County2
• Kenosha County2
• Chippewa County2
• Clark County2
• Jackson County2
• Eau Claire County2
• Vernon County2
• Dane County1
• Rusk County1
• Taylor County1
• La Crosse County1
• Monroe County1
• Marathon County1
• Door County1

1. June 19, 20097flash flood warnings
2. August 14, 20097flash flood warnings
3. July 24, 20094flash flood warnings
4. August 8, 20094flash flood warnings
5. June 22, 20093flash flood warnings
6. August 9, 20093flash flood warnings
7. July 28, 20092flash flood warnings
8. August 10, 20092flash flood warnings
9. April 27, 20091flash flood warnings
10. June 20, 20091flash flood warnings
11. July 27, 20091flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20082010

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.