Alert archive / South Carolina / Flash Flood Warnings

Flash Flood Warnings in South Carolina, 2009

38 flash flood warnings in 2009. An alert counts here when it covered any part of the state, so the counties below add up to more than the state. The archive of flash flood warnings reaches back to 1986.

Flash Flood Warnings by county

Each county as a circle sized by its count in 2009. Tap one for its archive.

Flash Flood Warnings
38
Busiest month
May9 flash flood warnings
Busiest day
May 27, 20093 flash flood warnings

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

26 of 41 flash flood warnings covering South Carolina in 2009 had a flash flood report inside them; 59 of 70 flash flood reports fell inside a warning, on average 65 minutes after it went out.

South Carolina, 2009

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Flash flood warnings412637%7084%65 min

Each office's whole area, 2009

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Greenville-Spartanburg, SC: flash flood warnings554027%10373%94 min
NWS Columbia, SC: flash flood warnings17947%2181%32 min
NWS Wilmington, NC: flash flood warnings220%6100%65 min
NWS Charleston, SC: flash flood warnings201430%4391%59 min

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.

The alerts

Every alert, in the order issued. Times are local, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.

IssuedProductOfficeCountiesLasted
May 14, 1:46 PM EDTFlash Flood WarningCHSBerkeley, Charleston100 min
May 15, 3:16 PM EDTFlash Flood WarningCHSBerkeley, Charleston71 min
May 24, 1:17 PM EDTFlash Flood WarningCAERichland118 min
May 25, 6:04 PM EDTFlash Flood WarningCAEOrangeburg116 min
May 25, 6:25 PM EDTFlash Flood WarningCAEBamberg, Barnwell, Fairfield, Lexington, Newberry, Richland and 1 more44 hr
May 26, 8:19 AM EDTFlash Flood WarningGSPCherokee3 hr
May 27, 10:01 AM EDTFlash Flood WarningGSPAnderson, Greenville, Pickens2 hr
May 27, 12:46 PM EDTFlash Flood WarningCAENewberry112 min
May 27, 3:17 PM EDTFlash Flood WarningCHSCharleston97 min
Jun 4, 8:09 PM EDTFlash Flood WarningGSPYork3 hr
Jun 5, 8:24 PM EDTFlash Flood WarningCAERichland3 hr
Jun 18, 3:14 AM EDTFlash Flood WarningGSPChester3 hr
Jul 6, 10:06 PM EDTFlash Flood WarningCAEClarendon, Sumter114 min
Jul 8, 1:22 PM EDTFlash Flood WarningGSPAbbeville, Anderson4 hr
Jul 8, 7:17 PM EDTFlash Flood WarningCHSBerkeley, Charleston, Dorchester118 min
Jul 8, 8:05 PM EDTFlash Flood WarningCHSBeaufort, Charleston, Colleton, Dorchester115 min
Jul 8, 8:44 PM EDTFlash Flood WarningCHSCharleston2 hr
Jul 13, 4:58 PM EDTFlash Flood WarningILMGeorgetown3 hr
Jul 22, 10:33 PM EDTFlash Flood WarningGSPYork2 hr
Jul 22, 10:54 PM EDTFlash Flood WarningCAELexington, Richland6 hr
Jul 28, 7:37 PM EDTFlash Flood WarningGSPYork3 hr
Aug 22, 4:48 PM EDTFlash Flood WarningCHSCharleston4 hr
Aug 25, 4:18 PM EDTFlash Flood WarningCHSBerkeley33 min
Sep 18, 9:56 AM EDTFlash Flood WarningCHSBeaufort2 hr
Sep 18, 10:33 AM EDTFlash Flood WarningCHSBeaufort58 min
Sep 20, 4:30 AM EDTFlash Flood WarningGSPOconee4 hr
Sep 20, 6:07 AM EDTFlash Flood WarningGSPOconee3 hr
Sep 25, 7:15 PM EDTFlash Flood WarningGSPCherokee, Spartanburg, York2 hr
Nov 11, 2:08 AM ESTFlash Flood WarningGSPGreenville, Spartanburg6 hr
Dec 2, 6:54 AM ESTFlash Flood WarningCHSBerkeley, Charleston, Colleton, Dorchester3 hr
Dec 2, 1:26 PM ESTFlash Flood WarningGSPAnderson4 hr
Dec 2, 2:14 PM ESTFlash Flood WarningGSPAnderson, Greenville, Spartanburg3 hr
Dec 9, 8:04 AM ESTFlash Flood WarningCAERichland36 min
Dec 18, 3:55 PM ESTFlash Flood WarningCHSBerkeley, Charleston6 hr
Dec 18, 5:32 PM ESTFlash Flood WarningCHSBerkeley, Charleston4 hr
Dec 25, 9:52 AM ESTFlash Flood WarningCAERichland3 hr
Dec 25, 11:41 AM ESTFlash Flood WarningCAELexington, Richland64 min
Dec 25, 12:10 PM ESTFlash Flood WarningCAEChesterfield, Fairfield, Kershaw, Lancaster2 hr

By county

Every county with at least one alert. A county page lists each alert that covered it.

The busiest days

Days with the most alerts issued, by UTC date.

  1. May 27, 20093flash flood warnings
  2. December 2, 20093flash flood warnings
  3. December 25, 20093flash flood warnings
  4. May 25, 20092flash flood warnings
  5. July 8, 20092flash flood warnings
  6. July 9, 20092flash flood warnings
  7. July 23, 20092flash flood warnings
  8. September 18, 20092flash flood warnings
  9. September 20, 20092flash flood warnings
  10. December 18, 20092flash flood warnings
  11. May 14, 20091flash flood warnings
  12. May 15, 20091flash flood warnings

Nearby

Alerts in force nowTornadoes on recordThe radar archive20082010

Sources

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.