Tornado Warnings in South Dakota, 2015

By month

19 of 52 tornado warnings covering South Dakota in 2015 had a tornado report inside them; 23 of 32 tornado reports fell inside a warning, on average 14 minutes after it went out.

South Dakota, 2015

Each office's whole area, 2015

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.

• Roberts County8
• Sanborn County6
• Miner County6
• Day County6
• Marshall County5
• Codington County5
• Davison County4
• Perkins County4
• Grant County4
• Deuel County4
• Hutchinson County3
• Hanson County3
• Lake County3
• Beadle County3
• Douglas County2
• Clay County2
• Turner County2
• Lawrence County2
• Meade County2
• Ziebach County2
• Jerauld County2
• Tripp County2
• Clark County2
• Hamlin County2
• Kingsbury County2
• Brookings County2
• Charles Mix County1
• Lincoln County1
• Union County1
• Yankton County1
• Butte County1
• Pennington County1
• Haakon County1
• Harding County1
• Bennett County1
• Jackson County1
• Todd County1
• McCook County1
• Minnehaha County1
• McPherson County1

1. July 18, 201511tornado warnings
2. May 10, 20156tornado warnings
3. June 22, 20156tornado warnings
4. July 24, 20155tornado warnings
5. July 6, 20154tornado warnings
6. June 7, 20153tornado warnings
7. June 20, 20153tornado warnings
8. July 17, 20153tornado warnings
9. June 28, 20152tornado warnings
10. August 6, 20152tornado warnings
11. May 11, 20151tornado warnings
12. June 18, 20151tornado warnings

Alerts in force nowTornadoes on recordThe radar archive20142016

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.