Alert archive / South Carolina / Flash Flood Warnings
Flash Flood Warnings in South Carolina, 2020
44 flash flood warnings in 2020. 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 2020. Tap one for its archive.
- Flash Flood Warnings
- 44
- Busiest month
- September11 flash flood warnings
- Busiest day
- September 17, 202011 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.
31 of 44 flash flood warnings covering South Carolina in 2020 had a flash flood report inside them; 82 of 105 flash flood reports fell inside a warning, on average 99 minutes after it went out.
South Carolina, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Flash flood warnings | 44 | 31 | 30% | 105 | 78% | 99 min |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Columbia, SC: flash flood warnings | 20 | 17 | 15% | 74 | 86% | 66 min |
| NWS Greenville-Spartanburg, SC: flash flood warnings | 79 | 42 | 47% | 138 | 71% | 121 min |
| NWS Wilmington, NC: flash flood warnings | 10 | 8 | 20% | 30 | 83% | 82 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.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 6, 5:40 AM EST | Flash Flood Warning | GSP | Oconee, Pickens | 14 hr |
| Feb 6, 5:59 AM EST | Flash Flood Warning | GSP | Greenville | 13 hr |
| Feb 6, 7:44 AM EST | Flash Flood Warning | GSP | Spartanburg | 12 hr |
| Feb 6, 10:03 AM EST | Flash Flood Warning | GSP | Anderson, Greenville, Pickens | 9 hr |
| Feb 6, 11:04 AM EST | Flash Flood Warning | GSP | Pickens | 12 hr |
| Feb 6, 1:27 PM EST | Flash Flood Warning | GSP | Abbeville, Greenwood | 8 hr |
| Feb 6, 1:54 PM EST | Flash Flood Warning | GSP | Chester, Laurens, Union, York | 6 hr |
| Feb 6, 3:11 PM EST | Flash Flood Warning | GSP | Greenville | 6 hr |
| Feb 6, 6:55 PM EST | Flash Flood Warning | GSP | Greenville | 2 hr |
| Apr 30, 1:49 AM EDT | Flash Flood Warning | GSP | York | 4 hr |
| May 19, 1:23 PM EDT | Flash Flood Warning | GSP | Greenville, Spartanburg | 3 hr |
| May 20, 5:55 AM EDT | Flash Flood Warning | GSP | Anderson, Greenville | 6 hr |
| May 24, 8:51 PM EDT | Flash Flood Warning | CAE | Lexington, Richland | 84 min |
| May 28, 6:06 PM EDT | Flash Flood Warning | ILM | Marion | 3 hr |
| May 28, 8:36 PM EDT | Flash Flood Warning | CAE | Chesterfield | 3 hr |
| May 28, 8:59 PM EDT | Flash Flood Warning | CAE | Chesterfield, Kershaw, Lancaster | 3 hr |
| May 29, 10:12 PM EDT | Flash Flood Warning | CAE | Lexington, Richland | 2 hr |
| May 29, 10:34 PM EDT | Flash Flood Warning | CAE | Calhoun, Clarendon, Richland, Sumter | 116 min |
| May 30, 12:29 AM EDT | Flash Flood Warning | CAE | Calhoun, Clarendon, Richland, Sumter | 3 hr |
| Jun 24, 4:10 PM EDT | Flash Flood Warning | CAE | Lexington, Richland | 85 min |
| Jun 24, 6:46 PM EDT | Flash Flood Warning | CAE | Lancaster | 119 min |
| Jul 7, 10:53 AM EDT | Flash Flood Warning | CAE | Edgefield, McCormick | 4 hr |
| Jul 29, 7:57 PM EDT | Flash Flood Warning | CAE | Calhoun, Lexington, Richland | 2 hr |
| Aug 6, 6:58 PM EDT | Flash Flood Warning | CAE | Lexington, Richland | 3 hr |
| Aug 15, 5:24 PM EDT | Flash Flood Warning | GSP | Spartanburg | 2 hr |
| Aug 15, 6:35 PM EDT | Flash Flood Warning | GSP | Chester, York | 88 min |
| Sep 17, 8:30 AM EDT | Flash Flood Warning | CAE | Aiken, Edgefield, McCormick | 3 hr |
| Sep 17, 9:00 AM EDT | Flash Flood Warning | GSP | Abbeville, Anderson | 5 hr |
| Sep 17, 9:22 AM EDT | Flash Flood Warning | CAE | Aiken, Barnwell, Edgefield, McCormick, Newberry, Saluda | 3 hr |
| Sep 17, 9:43 AM EDT | Flash Flood Warning | GSP | Oconee, Pickens | 4 hr |
| Sep 17, 10:28 AM EDT | Flash Flood Warning | CAE | Bamberg, Calhoun, Clarendon, Orangeburg, Richland, Sumter | 3 hr |
| Sep 17, 10:38 AM EDT | Flash Flood Warning | CAE | Aiken, Bamberg, Barnwell, Calhoun, Fairfield, Kershaw and 6 more | 3 hr |
| Sep 17, 12:06 PM EDT | Flash Flood Warning | CAE | Clarendon, Kershaw, Lee, Richland, Sumter | 3 hr |
| Sep 17, 1:08 PM EDT | Flash Flood Warning | ILM | Darlington, Florence | 3 hr |
| Sep 17, 1:34 PM EDT | Flash Flood Warning | CAE | Calhoun, Clarendon, Orangeburg, Richland, Sumter | 3 hr |
| Sep 17, 2:54 PM EDT | Flash Flood Warning | ILM | Darlington, Dillon, Florence, Marlboro | 3 hr |
| Sep 17, 3:19 PM EDT | Flash Flood Warning | CAE | Clarendon, Lee, Sumter | 3 hr |
| Oct 29, 7:36 AM EDT | Flash Flood Warning | GSP | Greenville | 7 hr |
| Nov 11, 4:19 PM EST | Flash Flood Warning | CAE | Orangeburg | 3 hr |
| Nov 12, 6:42 AM EST | Flash Flood Warning | GSP | Greenwood, Laurens | 3 hr |
| Nov 12, 6:46 AM EST | Flash Flood Warning | GSP | Cherokee, Union, York | 3 hr |
| Nov 12, 7:40 AM EST | Flash Flood Warning | GSP | York | 10 hr |
| Nov 12, 8:16 AM EST | Flash Flood Warning | GSP | Chester, Union | 4 hr |
| Nov 26, 9:23 AM EST | Flash Flood Warning | CAE | Lexington, Richland | 36 min |
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Richland County12
- Greenville County7
- Lexington County7
- Sumter County7
- Calhoun County6
- Clarendon County6
- York County5
- Pickens County4
- Orangeburg County4
- Spartanburg County3
- Anderson County3
- Chester County3
- Union County3
- Kershaw County3
- Edgefield County3
- McCormick County3
- Aiken County3
- Oconee County2
- Abbeville County2
- Greenwood County2
- Laurens County2
- Chesterfield County2
- Lancaster County2
- Barnwell County2
- Newberry County2
- Saluda County2
- Bamberg County2
- Lee County2
- Darlington County2
- Florence County2
- Marion County1
- Fairfield County1
- Dillon County1
- Marlboro County1
- Cherokee County1
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20192021
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.