Alert archive / South Carolina

Weather alerts in South Carolina, 2016

2,678 weather alerts in 2016, 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 2016. Tap one for its archive.

Alerts
2,678
Warnings
777
Watches
83
Advisories
496
Busiest month
July767 alerts
Busiest day
July 9, 201668 alerts

Over time

By month

Warning verification

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

3 of 27 tornado warnings covering South Carolina in 2016 had a tornado report inside them; 7 of 8 tornado reports fell inside a warning, on average 37 minutes after it went out.

South Carolina, 2016

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Tornado warnings27389%888%37 min
Severe thunderstorm warnings47037221%82486%21 min
Flash flood warnings373214%13786%141 min

Each office's whole area, 2016

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Columbia, SC: tornado warnings6183%250%13 min
NWS Columbia, SC: severe thunderstorm warnings19216315%32487%21 min
NWS Columbia, SC: flash flood warnings141214%4596%71 min
NWS Greenville-Spartanburg, SC: tornado warnings8275%6100%41 min
NWS Greenville-Spartanburg, SC: severe thunderstorm warnings24818525%53680%18 min
NWS Greenville-Spartanburg, SC: flash flood warnings231917%7987%91 min
NWS Wilmington, NC: tornado warnings200100%10%
NWS Wilmington, NC: severe thunderstorm warnings1248631%18883%20 min
NWS Wilmington, NC: flash flood warnings201620%5695%172 min
NWS Charleston, SC: tornado warnings12283%520%27 min
NWS Charleston, SC: severe thunderstorm warnings1288831%33480%22 min
NWS Charleston, SC: flash flood warnings121017%5966%211 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

2,678 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.

6 more counties

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force nowTornadoes on recordThe radar archive20152017

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.