Hail, Perkins
- When
- July 23, 5:30 PM MST
- Where
- Perkins County, 7 mi SW of Shadehill
- Measured
- 1 in hail
- Reported by
- Public
- Coordinates
- 45.698, -102.283
Hail and Damaging Winds in South Dakota, July 23, 2021
A supercell thunderstorm developed over north central Perkins County and tracked east across northeastern portions of the county, producing large hail and wind gusts to 60 mph.
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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 5
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.
A supercell thunderstorm developed over north central Perkins County and tracked east across northeastern portions of the county, producing large hail and wind gusts to 60 mph.
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 Jul 23, 4:30 PM MST, 1 hour earlier.
Area forecast discussion, Jul 23, 4:30 PM MST, 1 hour before
Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 530 PM MDT Fri Jul 23 2021 .DISCUSSION...(This Evening Through Friday) Issued at 1230 PM MDT Fri Jul 23 2021 The latest water vapor images and RAP model 500-mb height analysis showed an upper high anchored over the Southwest U.S. with quasi-zonal flow across the CWA. One short-wave trough was evident over central/eastern WY and it was associated with considerable cloud cover. This will dampen heating and thus result in less MLCAPE and more MLCIN than previously expected. Better insolation was over central SD, which should be more favorable for later convective development. Otherwise, another short-wave trough was moving across central MT in association with a 70-90kt jet streak. Q-vector convergence supports stronger lift with this system; lapse rates, CAPE, and 0-6km bulk shear will be better with this wave, and thus convective development appears better. Based on this and the CAMs it seems probable that weaker storms will form over the BLKHLS, with strong-to-severe storms (and supercells) over parts of northwestern into central SD, and then some severe storms with a wind threat over south-central SD where inverted-V soundings, a weak boundary, and weaker 0-6km shear exist. PWATs of 150-200 percent of average favor locally heavy rain, but the lack of a focusing boundary and mean winds of 15-20kt should preclude organized heavy rainfall. Otherwise, these storms/small MCSs should be mostly east of the CWA by 04z. Convection will be relatively diminished Saturday and Sunday as the monsoonal moisture plume is shunted south of the CWA. However, some warm advection and steeper lapse rates over the southwestern CWA will favor elevated storms late Saturday, and possibly Sunday too as monsoonal moisture creeps back into the CWA. Monday through Wednesday look to be exceptionally hot as the Southwest U.S. upper high builds northward. Record highs and record high lows appear likely on Tuesday based on the latest ensemble and NBM guidance. The main limiting factor is the potential for smoke to reduce insolation. The upper ridge then appears to retrograde Thursday and Friday as upper low pressure deepens over the Hudson Bay area. Monsoonal moisture also should spread back across the CWA. This will bring a modest reprieve from the heat along with slightly better chances of showers and thunderstorms. && .AVIATION...For the 00Z TAFS Through 00Z Saturday Evening Issued At 523 PM MDT Fri Jul 23 2021 Thick band of mid level clouds streaming over southwestern into central SD will shift to the east overnight, leaving mostly clear skies Saturday. Thunderstorms moving across northwestern SD. Heavier smoke is moving into northeastern WY and will spread across the area, reducing visibility occasionally. && .FIRE WEATHER... Issued At 1230 PM MDT Fri Jul 23 2021 Minimum relative humidities will fall to 10-15 percent on Monday and Tuesday across northeastern WY and northwestern SD as high temperatures soar into the upper 90s and 100s across most of the area. However, at this time it appears that wind speeds will remain below red flag warning criteria. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && DISCUSSION...Bunkers AVIATION...55 FIRE WEATHER...Bunkers
Hazardous weather outlook, Jul 23, 10:06 AM MST, 7 hours 24 minutes before
Hazardous Weather Outlook National Weather Service Rapid City SD 1106 AM MDT Fri Jul 23 2021 SDZ002-014-046-047-049-241300- Perkins-Ziebach-Mellette-Todd-Tripp- 1106 AM MDT Fri Jul 23 2021 /1206 PM CDT Fri Jul 23 2021/ This Hazardous Weather Outlook is for portions of northwestern and south central South Dakota. .DAY ONE...TODAY AND TONIGHT There is a slight risk of severe thunderstorms this afternoon and evening. Large hail and damaging winds are possible over northwestern South Dakota, while thunderstorms may produce locally damaging winds across south central South Dakota. .DAYS TWO THROUGH SEVEN...Saturday through Thursday There is a chance of thunderstorms Saturday and Sunday. Severe thunderstorms are not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity SDZ001-012-013-024>032-041>044-072>074-241300- Harding-Butte-Northern Meade Co Plains-Northern Black Hills- Northern Foot Hills-Rapid City-Southern Foot Hills- Central Black Hills-Southern Black Hills-Custer Co Plains- Pennington Co Plains-Haakon-Fall River-Oglala Lakota-Jackson- Bennett-Sturgis/Piedmont Foot Hills-Southern Meade Co Plains- Hermosa Foot Hills- 1106 AM MDT Fri Jul 23 2021 This Hazardous Weather Outlook is for portions of northwestern and southwestern South Dakota...and the Black Hills of South Dakota. .DAY ONE...TODAY AND TONIGHT Isolated severe thunderstorms may produce large hail and damaging winds this afternoon and evening. .DAYS TWO THROUGH SEVEN...Saturday through Thursday There is a chance of thunderstorms Saturday and Sunday. Severe thunderstorms are not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity WYZ054>058-071-241300- Northern Campbell-Southern Campbell-Western Crook- Wyoming Black Hills-Weston-Northeastern Crook- 1106 AM MDT Fri Jul 23 2021 This Hazardous Weather Outlook is for portions of northeast Wyoming...and the Black Hills of Wyoming. .DAY ONE...Today and Tonight There is a chance of thunderstorms this afternoon and evening. Severe thunderstorms are not expected at this time. .DAYS TWO THROUGH SEVEN...Saturday through Thursday There is a chance of thunderstorms Saturday and Sunday. Severe thunderstorms are not expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation will not be needed today. && Stay tuned to NOAA weather radio for further updates...or check our web site at weather.gov/rapidcity
In the hours before
Special weather statement, Jul 23, 4:03 PM MST, 1 hour 27 minutes before
Special Weather Statement National Weather Service Rapid City SD 503 PM MDT Fri Jul 23 2021 SDZ001-002-232345- Perkins SD-Harding SD- 503 PM MDT Fri Jul 23 2021 ...STRONG THUNDERSTORM OVER EAST CENTRAL HARDING AND SOUTHWESTERN PERKINS COUNTIES... At 503 PM MDT, Doppler radar was tracking a strong thunderstorm near Sorum, or 33 miles east of Buffalo, moving east at 25 mph. Penny size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Sorum and Date. LAT...LON 4541 10301 4552 10294 4546 10251 4524 10267 TIME...MOT...LOC 2303Z 288DEG 20KT 4543 10289 Helgeson
Special weather statement, Jul 23, 4:13 PM MST, 1 hour 17 minutes before
Special Weather Statement National Weather Service Rapid City SD 513 PM MDT Fri Jul 23 2021 SDZ012-013-240000- Butte SD-Northern Meade Co Plains SD- 513 PM MDT Fri Jul 23 2021 ...STRONG THUNDERSTORM OVER EAST CENTRAL BUTTE AND NORTH CENTRAL MEADE COUNTIES... At 513 PM MDT, Doppler radar was tracking a strong thunderstorm 10 miles southwest of Mud Butte, or 41 miles northeast of Sturgis, moving east at 25 mph. Nickel size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Fairpoint. PRECAUTIONARY/PREPAREDNESS ACTIONS... This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 4489 10311 4495 10302 4492 10259 4473 10278 TIME...MOT...LOC 2313Z 288DEG 20KT 4490 10302 Helgeson
Local storm report, Jul 23, 4:44 PM MST, 46 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RAPID CITY SD
544 PM MDT FRI JUL 23 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0532 PM HAIL 3 SSE SORUM 45.41N 102.92W
07/23/2021 E1.25 INCH PERKINS SD TRAINED SPOTTER
WIND GUST ESTIMATED AT 40 MPH
&&
MLSSpecial weather statement, Jul 23, 5:08 PM MST, 22 minutes before
Special Weather Statement National Weather Service Rapid City SD 608 PM MDT Fri Jul 23 2021 SDZ002-240115- Perkins SD- 608 PM MDT Fri Jul 23 2021 ...STRONG THUNDERSTORM OVER NORTHEASTERN PERKINS COUNTY... At 607 PM MDT, Doppler radar was tracking a strong thunderstorm 9 miles north of Bison, or 23 miles southwest of Lemmon, moving east at 20 mph. Nickel size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Meadow and Shadehill Reservoir. PRECAUTIONARY/PREPAREDNESS ACTIONS... If on or near Shadehill Reservoir, get out of the water and move indoors or inside a vehicle. Remember, lightning can strike out to 10 miles from the parent thunderstorm. If you can hear thunder, you are close enough to be struck by lightning. Move to safe shelter now! Do not be caught on the water in a thunderstorm. Persons in campgrounds should consider seeking sturdy shelter until this storm passes. && A Severe Thunderstorm Watch remains in effect until 100 AM MDT for northwestern South Dakota. LAT...LON 4549 10200 4560 10255 4573 10255 4577 10200 TIME...MOT...LOC 0007Z 275DEG 19KT 4567 10244 Helgeson
The radar
The Bismarck radar (KBIS), 167 km away, was scanning. The volume nearest the first event began at 00:29 UTC.
Event by event
3 hail, 2 thunderstorm wind. Local standard time, as filed.
Hail, Perkins
- When
- July 23, 6:20 PM MST
- Where
- Perkins County, 7 mi E of Lemmon
- Measured
- 1 in hail
- Reported by
- Public
- Coordinates
- 45.940, -102.014
Thunderstorm Wind, Perkins
- When
- July 23, 6:20 PM MST
- Where
- Perkins County, 6 mi E of Lemmon
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- Public
- Coordinates
- 45.940, -102.035
Wind gusts were estimated at 60 mph.
Hail, Perkins
- When
- July 23, 6:25 PM MST
- Where
- Perkins County, 6.13 mi ESE of (Lem)lemmon Arpt
- Measured
- 1 in hail
- Reported by
- Public
- Coordinates
- 45.890, -102.000
Thunderstorm Wind, Perkins
- When
- July 23, 6:25 PM MST
- Where
- Perkins County, 6.13 mi ESE of (Lem)lemmon Arpt
- Measured
- 52 kt (60 mph) estimated gust
- Reported by
- Public
- Coordinates
- 45.890, -102.000
Wind gusts were estimated at 60 mph.
What these are
- Hail
- Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Flash Flooding and Heavy Rain in Arizona, July 23 to 25, 2021
- Tornado and Flash Flooding in New Mexico, July 23, 2021
- Flash Flood in Colorado, July 23, 2021
- Damaging Winds in Minnesota, July 23 to 24, 2021
- Damaging Winds in Georgia, July 23, 2021
- Flash Flood and Debris Flows in Colorado, July 23, 2021
- Flooding and Damaging Winds in Florida, July 23, 2021
- Damaging Winds in South Dakota, July 23, 2021
- Flash Flooding and Heavy Rain in Arizona, July 23 to 24, 2021
- Hail and Damaging Winds in New Hampshire, July 23, 2021
- Hail and Damaging Wind in Massachusetts, July 23, 2021
- Hail and Damaging Winds in Minnesota, July 23 to 24, 2021
More
Every storm in South Dakota in 2021Every state in 2021This day in weather historyWarnings in South Dakota, July 2021
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: 970171, 970173, 970185, 970186, 970188.