1 lightning, as filed by the National Weather Service.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Sioux Falls, SD wrote its last area forecast discussion before the first event at Aug 21, 7:25 PM CST, 3 hours 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SIOUX FALLS SD 825 PM CDT WED AUG 21 2002 SEVERE THUNDERSTORM OVER GREGORY COUNTY WEAKENING RAPIDLY WITH JUST SOME ISOLATED THUNDERSTORMS OVER THE JAMES VALLEY. FRONT STRETCHING FROM ABOUT VTN TO YKN TO LSE. WATER VAPOR LOOP SHOWING TWO WAVES...ONE ACROSS CO AND ANOTHER MOVING NORTH INTO SOUTHERN SD. THIS LIKELY HELPED SPARK THE THUNDERSTORMS BUT PROFILERS NOT SHOWING ANY BACKING OF THE WINDS SO APPARENTLY FAIRLY WEAK. WITH THE LOW LEVEL JET VEERED TO THE SOUTHWEST...AND EXPECTED TO VEER FURTHER TO THE WEST...WE MAY NOT SEE A VERY EXPANSIVE AREA OF SHOWERS AND THUNDERSTORMS TONIGHT. WITH THE MAIN WAVE WELL OFF TO OUR WEST...WEAK SHEAR AND VERY LITTLE LOW LEVEL FORCING EXPECTED...WILL BACK OFF TO ISOLATED TO SCATTERED WORDING IN FORECAST PACKAGE. BELIEVE THAT THE BEST CONVECTION WILL BE TO OUR EAST AND SOUTH OVERNIGHT. .FSD...NONE 08
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SIOUX FALLS SD
721 PM CDT WED AUG 21 2002
TIME(CDT) .....CITY LOCATION.....STATE ...EVENT/REMARKS...
....COUNTY LOCATION....
0715 PM 5 N DALLAS SD 60 MPH TSTM GUST
08/21/02 GREGORY REPORTED BY PUBLIC.
TREE BRANCHES DOWN.The Aberdeen radar (KABR), 155 km away, was scanning. The volume nearest the first event began at 05:01 UTC.
1 lightning. Local standard time, as filed.
Lightning killed a cow, a bull, and four bull calves.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Dakota in 2002Every state in 2002This day in weather historyWarnings in South Dakota, August 2002
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5317688.