Alert archive / South Carolina
Weather alerts in South Carolina, 2012
3,051 weather alerts in 2012, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered any part of the state, so the counties below add up to more than the state.
Weather alerts by county
Each county as a circle sized by its count in 2012. Tap one for its archive.
- Alerts
- 3,051
- Warnings
- 945
- Watches
- 75
- Advisories
- 556
- Busiest month
- July795 alerts
- Busiest day
- July 10, 201285 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
6 of 31 tornado warnings covering South Carolina in 2012 had a tornado report inside them; 7 of 13 tornado reports fell inside a warning, on average 4 minutes after it went out.
South Carolina, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 31 | 6 | 81% | 13 | 54% | 4 min |
| Severe thunderstorm warnings | 752 | 557 | 26% | 1,047 | 86% | 23 min |
| Flash flood warnings | 28 | 19 | 32% | 70 | 87% | 92 min |
Each office's whole area, 2012
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Charleston, SC: tornado warnings | 18 | 2 | 89% | 7 | 43% | 1 min |
| NWS Charleston, SC: severe thunderstorm warnings | 253 | 181 | 28% | 444 | 83% | 25 min |
| NWS Charleston, SC: flash flood warnings | 11 | 6 | 45% | 31 | 87% | 144 min |
| NWS Greenville-Spartanburg, SC: tornado warnings | 15 | 0 | 100% | 1 | 0% | |
| NWS Greenville-Spartanburg, SC: severe thunderstorm warnings | 581 | 410 | 29% | 722 | 89% | 23 min |
| NWS Greenville-Spartanburg, SC: flash flood warnings | 33 | 19 | 42% | 47 | 79% | 46 min |
| NWS Columbia, SC: tornado warnings | 9 | 3 | 67% | 5 | 60% | 4 min |
| NWS Columbia, SC: severe thunderstorm warnings | 246 | 183 | 26% | 396 | 86% | 22 min |
| NWS Columbia, SC: flash flood warnings | 14 | 12 | 14% | 39 | 90% | 46 min |
| NWS Wilmington, NC: tornado warnings | 11 | 1 | 91% | 1 | 100% | 9 min |
| NWS Wilmington, NC: severe thunderstorm warnings | 162 | 103 | 36% | 264 | 82% | 25 min |
| NWS Wilmington, NC: flash flood warnings | 1 | 1 | 0% | 3 | 100% | 57 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
3,051 alerts are too many to list on one page. Narrow it to a product above, to a month in the chart, or to a county.
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
By county
Every county with at least one alert. A county page lists each alert that covered it.
- Berkeley County302
- Horry County264
- Georgetown County224
- Colleton County221
- Greenville County211
- Florence County207
- Richland County205
- Lexington County202
- Laurens County199
- Marion County195
- Dorchester County193
- Dillon County191
- York County190
- Williamsburg County186
- Marlboro County184
- Hampton County182
- Charleston County179
- Kershaw County176
- Spartanburg County176
- Darlington County175
- Calhoun County174
- Anderson County171
- Cherokee County168
- Union County166
- Aiken County164
- Chester County164
- Sumter County162
- Clarendon County157
- Fairfield County155
- Pickens County155
- Jasper County155
- Greenwood County152
- Chesterfield County151
- Abbeville County144
- Allendale County144
- Bamberg County139
- Newberry County139
- Barnwell County137
- Lee County136
- Beaufort County132
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordThe radar archive20112013
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.