Flash Flood Warnings in South Carolina, 2011

By month

9 of 25 flash flood warnings covering South Carolina in 2011 had a flash flood report inside them; 14 of 19 flash flood reports fell inside a warning, on average 33 minutes after it went out.

South Carolina, 2011

Each office's whole area, 2011

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.

• Richland County11
• Charleston County5
• Berkeley County4
• Jasper County2
• Dorchester County2
• Lee County2
• Oconee County1
• Lexington County1
• Beaufort County1
• Colleton County1
• Fairfield County1
• Marlboro County1
• Georgetown County1
• Williamsburg County1
• York County1
• Calhoun County1
• Clarendon County1
• Sumter County1

1. August 12, 20114flash flood warnings
2. July 6, 20112flash flood warnings
3. August 13, 20112flash flood warnings
4. August 26, 20112flash flood warnings
5. September 21, 20112flash flood warnings
6. September 23, 20112flash flood warnings
7. March 6, 20111flash flood warnings
8. June 29, 20111flash flood warnings
9. July 14, 20111flash flood warnings
10. July 15, 20111flash flood warnings
11. July 27, 20111flash flood warnings
12. July 31, 20111flash flood warnings

Alerts in force nowTornadoes on recordThe radar archive20102012

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.