Severe thunderstorms developed across north central South Dakota around midnight and proceeded east through the overnight hours. Of particular note, a long-track supercell produced severe weather from just east of the Missouri River in Walworth County along the length of Highway 12 through the rest of the state, a distance of about 180 miles. Additional severe thunderstorms developed across the area during and after this long-track supercell dissipated, during the mid-morning. The strongest storms produced tennis to baseball sized hail and damaging wind gusts.
The hail was large and numerous enough to produce significant and virtually continuous crop damage for about 90 miles from west of Pembrook Colony in Edmunds County east to about Andover in Day County, as seen from satellite as a hail scar. This scar was about 6 miles wide in spots. The crop damage was more sporadic afterwards, though the hail scar was still discernable south of Waubay in Day County east to the north of Milbank in Grant County. Along with the crop damage, many buildings, windows, and vehicles were damaged along the storm's path. The large hail also killed deer and many birds.

Hail in DAY, SOUTH DAKOTA
From 28-AUG-21 05:03:00 to 28-AUG-21 05:03:00 (CST-6)
Location: WEBSTER MUNI ARPT
Magnitude: 1.75 
Reported by: Trained Spotter

Hail in GRANT, SOUTH DAKOTA
From 28-AUG-21 05:50:00 to 28-AUG-21 05:50:00 (CST-6)
Location: HILAND
Magnitude: 2.75 
Reported by: Public

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 06:10:00 to 28-AUG-21 06:10:00 (CST-6)
Location: LOYALTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BROWN, SOUTH DAKOTA
From 28-AUG-21 06:15:00 to 28-AUG-21 06:15:00 (CST-6)
Location: HOUGHTON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in GRANT, SOUTH DAKOTA
From 28-AUG-21 06:33:00 to 28-AUG-21 06:33:00 (CST-6)
Location: MILBANK
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in SPINK, SOUTH DAKOTA
From 28-AUG-21 07:08:00 to 28-AUG-21 07:08:00 (CST-6)
Location: MELLETTE
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in DAY, SOUTH DAKOTA
From 28-AUG-21 07:25:00 to 28-AUG-21 07:25:00 (CST-6)
Location: WEBSTER MUNI ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in DAY, SOUTH DAKOTA
From 28-AUG-21 07:30:00 to 28-AUG-21 07:30:00 (CST-6)
Location: WEBSTER MUNI ARPT
Magnitude: 2.50 
Reported by: Public

Thunderstorm Wind in GRANT, SOUTH DAKOTA
From 28-AUG-21 07:44:00 to 28-AUG-21 07:44:00 (CST-6)
Location: HILAND
Magnitude: 56.00 EG
Reported by: Public

Estimated wind speeds of 65 mph occurred.

Hail in GRANT, SOUTH DAKOTA
From 28-AUG-21 08:15:00 to 28-AUG-21 08:15:00 (CST-6)
Location: MILBANK
Magnitude: 2.50 
Reported by: Public

Hail in GRANT, SOUTH DAKOTA
From 28-AUG-21 08:19:00 to 28-AUG-21 08:19:00 (CST-6)
Location: MILBANK
Magnitude: 1.75 
Reported by: Trained Spotter

Hail in GRANT, SOUTH DAKOTA
From 28-AUG-21 08:35:00 to 28-AUG-21 08:35:00 (CST-6)
Location: BIG STONE CITY
Magnitude: 1.25 
Reported by: Public

Thunderstorm Wind in GRANT, SOUTH DAKOTA
From 28-AUG-21 08:44:00 to 28-AUG-21 08:44:00 (CST-6)
Location: BIG STONE CITY
Magnitude: 61.00 MG
Reported by: Mesonet

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 02:48:00 to 28-AUG-21 03:24:00 (CST-6)
Location: IPSWICH
Magnitude: 2.50 
Reported by: Emergency Manager

A hail swath determined by high resolution satellite imagery along with surface reports occurred from Edmunds County east across southern Brown into Day Counties.  The largest hail size was baseball size. The scar dimensions covered approximately 70 square miles in Edmunds County. The start location was approximately 5 miles southwest of Ipswich, and it continued in an east southeast orientation to the Brown County line approximately 5 miles south of Mina Lake. Drone and photo evidence of damage in this area suggest substantial to total crop losses.

Hail in BROWN, SOUTH DAKOTA
From 28-AUG-21 04:13:00 to 28-AUG-21 04:13:00 (CST-6)
Location: FERNEY
Magnitude: 2.75 
Reported by: Newspaper

Hail in BROWN, SOUTH DAKOTA
From 28-AUG-21 04:06:00 to 28-AUG-21 04:26:00 (CST-6)
Location: RANDOLPH
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A satellite depicted hail swath from a severe thunderstorm from Edmunds county continued across southern Brown County and then to the east northeast into Day County. Hail size was up to baseball along the storm's path. The scar dimensions covered approximately 120 square miles in Brown County.

Hail in BROWN, SOUTH DAKOTA
From 28-AUG-21 03:13:00 to 28-AUG-21 04:06:00 (CST-6)
Location: RUDOLPH
Magnitude: 2.75 
Reported by: Emergency Manager

A satellite depicted hail swath from a severe thunderstorm in Edmunds County continued into southern Brown County.  The storm continued to the east across southern Brown County into western Day county. Hail up to baseball size occurred with this storm which caused substantial crop losses according to satellite imagery and surface reports. The scar dimensions covered approximately 120 square miles in Brown County.

Hail in DAY, SOUTH DAKOTA
From 28-AUG-21 04:20:00 to 28-AUG-21 05:40:00 (CST-6)
Location: BUTLER
Magnitude: 2.50 
Reported by: Emergency Manager

A satellite depicted hail swath from a severe thunderstorm that started in Edmunds County across southern Brown County entered Day County continuing its crop damage.  The storm weakened as it moved into Roberts County. The scar dimensions covered approximately 60 square miles in Day County.

Hail in WALWORTH, SOUTH DAKOTA
From 28-AUG-21 00:35:00 to 28-AUG-21 00:35:00 (CST-6)
Location: GLENHAM
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WALWORTH, SOUTH DAKOTA
From 28-AUG-21 00:56:00 to 28-AUG-21 00:56:00 (CST-6)
Location: SELBY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in WALWORTH, SOUTH DAKOTA
From 28-AUG-21 01:32:00 to 28-AUG-21 01:32:00 (CST-6)
Location: LOWRY
Magnitude: 2.50 
Reported by: Trained Spotter

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 02:20:00 to 28-AUG-21 02:20:00 (CST-6)
Location: ROSCOE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 02:25:00 to 28-AUG-21 02:25:00 (CST-6)
Location: CRAVEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 02:48:00 to 28-AUG-21 02:48:00 (CST-6)
Location: IPSWICH
Magnitude: 1.75 
Reported by: Public

Golf ball sized hail broke ten windows at a residence.

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 03:00:00 to 28-AUG-21 03:00:00 (CST-6)
Location: MINA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in EDMUNDS, SOUTH DAKOTA
From 28-AUG-21 03:08:00 to 28-AUG-21 03:08:00 (CST-6)
Location: MINA
Magnitude: 2.50 
Reported by: Trained Spotter

Several house windows were broken by tennis ball size hail.

Hail in BROWN, SOUTH DAKOTA
From 28-AUG-21 03:30:00 to 28-AUG-21 03:30:00 (CST-6)
Location: RUDOLPH
Magnitude: 1.50 
Reported by: Trained Spotter

Hail in BROWN, SOUTH DAKOTA
From 28-AUG-21 03:34:00 to 28-AUG-21 03:34:00 (CST-6)
Location: WARNER
Magnitude: 1.75 
Reported by: Law Enforcement

Thunderstorm Wind in BROWN, SOUTH DAKOTA
From 28-AUG-21 04:03:00 to 28-AUG-21 04:03:00 (CST-6)
Location: VERDON
Magnitude: 70.00 EG
Reported by: Public

Silos were dented and augers were blown over 100 feet from large hail and estimated 80  mph winds.

Hail in DAY, SOUTH DAKOTA
From 28-AUG-21 04:44:00 to 28-AUG-21 04:44:00 (CST-6)
Location: BUTLER
Magnitude: 2.00 
Reported by: Law Enforcement

Windshields were broken and tree damage occurred from two inch hail.