Name: Hail in South Dakota, August 23, 2002
Start: 2002-08-23T13:31
End: 2002-08-23T14:20
Location: South Dakota

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 3

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.

What happened

The episode as NWS UNR wrote it up.

Several slow moving, severe thunderstorms moved across the Keystone area this day. Large hail was reported around Keystone from several storms moving over the same general area and produced hail to golfball size.

What forecasters said that day

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 Rapid City, SD wrote its last area forecast discussion before the first event at Aug 23, 1:15 PM MST, 16 minutes earlier.

Area forecast discussion, Aug 23, 1:15 PM MST, 16 minutes before

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
215 PM MDT FRI AUG 23 2002

STRONG UPR LOW OR/ID BDR SHOWING LITTLE MOVEMENT PER WATER VAPOR
IMAGERY. A JET STREAK IS DEPICTED OVER NRN UT...AND IS AIDING IN
CONVECTIVE DVLPMT ACRS THE NRN ROCKIES. TSTMS OVR THE BLKHLS HAVE
ALREADY REACHED SVR CRITERIA WITH LARGE HAIL. MAIN FCST CONCERNS
CENTERED AROUND HEAVY RAIN POTENTIAL THROUGH SAT...WITH THE
POSSIBILITY OF SOME STORMS CONTAINING LARGE HAIL.

EXPECT ACTIVITY TO CONT TO DEVELOP AND MOVE EWD ACRS THE CWFA
THROUGH SAT...AS 700MB TROF ROTATES THROUGH NRN PLAINS.  SE FLOW
WILL CONT TO DEEPEN...AND LATEST HODOGRAPHS INDICATE SHEAR WILL
INCREASE SOMEWHAT TONIGHT FOR POTENTIAL ROTATING UPDRAFTS. BIGGEST
CONCERN REMAINS HEAVY RAIN POTENTIAL AS STORM MOVEMENT WILL BE VERY
SLOW.

BY SAT NIGHT...700MB TROF MOVS N/E OF CWFA CUTTING OFF DEEP MOISTURE
SOURCE. HOWEVER...WILL NEED TO LEAVE POPS IN FCST THRU REMAINDER OF
3 DAY FCST AS MAIN UPR TROF REMAINS WEST OF AREA...KEEPING AREA
UNDER UNSTABLE SW FLOW ALOFT.

EXTENDED...TUE-WED STILL UNSETTLED AS UPR TROF CROSSES NRN PLAINS.
TEMPS SHOULD REMAIN WITHIN REACH OF CLIMO THESE DAYS. DRIER WITH
WARMING TREND EXPECTED THU-FRI AS UPR RIDGE BUILDS ACRS REGION IN
ADVANCE OF WEST COAST TROF.

.UNR...FLOOD WATCH THIS AFTN THRU SAT EVE FOR LAWRENCE COUNTY.
JOHNSON

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 hail. Local standard time, as filed.

Hail, Pennington

When: August 23, 1:31 PM MST
Where: Pennington County, Keystone
Measured: 1.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 43.900, -103.417

Hail, Pennington

When: August 23, 2:05 PM MST
Where: Pennington County, 3 mi N of Keystone
Measured: 1 in hail
Reported by: TRAINED SPOTTER
Coordinates: 43.950, -103.417

Hail, Pennington

When: August 23, 2:20 PM MST
Where: Pennington County, 1 mi W of Keystone
Measured: 1.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 43.900, -103.433

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

Every storm in South Dakota in 2002 Every state in 2002 This day in weather history Warnings in South Dakota, August 2002

Sources

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: 5310720, 5310718, 5310719.