Tornado Warnings in South Dakota, 2017

By month

8 of 43 tornado warnings covering South Dakota in 2017 had a tornado report inside them; 11 of 18 tornado reports fell inside a warning, on average 16 minutes after it went out.

South Dakota, 2017

Each office's whole area, 2017

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.

• Day County7
• Charles Mix County6
• Spink County5
• Brookings County5
• Clark County5
• Gregory County4
• Aurora County4
• Codington County4
• Oglala Lakota County3
• Hand County3
• Douglas County3
• Brown County3
• Marshall County3
• McPherson County3
• Fall River County2
• Brule County2
• Davison County2
• Beadle County2
• Sanborn County2
• Roberts County2
• Moody County2
• Bon Homme County2
• McCook County2
• Lincoln County1
• Bennett County1
• Faulk County1
• Jerauld County1
• Union County1
• Tripp County1
• Kingsbury County1
• Campbell County1
• Edmunds County1
• Walworth County1
• Grant County1
• Lake County1
• Minnehaha County1

1. June 13, 201717tornado warnings
2. September 20, 201712tornado warnings
3. August 13, 20173tornado warnings
4. July 12, 20172tornado warnings
5. July 25, 20172tornado warnings
6. May 17, 20171tornado warnings
7. June 14, 20171tornado warnings
8. June 29, 20171tornado warnings
9. August 12, 20171tornado warnings
10. August 25, 20171tornado warnings
11. August 26, 20171tornado warnings
12. September 16, 20171tornado warnings

Alerts in force nowTornadoes on recordThe radar archive20162018

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.