A severe thunderstorm developed over the northeastern slopes of the Black Hills and tracked slowly southeast through the Rapid City area before weakening east of the Black Hills. The storm produced hail to golf ball size, wind gusts over 60 mph, and heavy rain. Some of the largest hail fell on the north and west sides of Rapid City.

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:00:00 to 14-AUG-17 17:00:00 (MST-7)
Location: HISEGA
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 16:30:00 to 14-AUG-17 16:30:00 (MST-7)
Location: JOHNSON SIDING
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:20:00 to 14-AUG-17 17:20:00 (MST-7)
Location: RAPID CITY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:11:00 to 14-AUG-17 17:11:00 (MST-7)
Location: RAPID CITY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated around 60 mph.

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:08:00 to 14-AUG-17 17:08:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in MEADE, SOUTH DAKOTA
From 14-AUG-17 16:15:00 to 14-AUG-17 16:15:00 (MST-7)
Location: PIEDMONT
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Rain in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 16:30:00 to 14-AUG-17 17:30:00 (MST-7)
Location: RAPID CITY
Crop damage: 0.00K
Reported by: Trained Spotter

One to two inches of rain in the Rapid City area caused minor street flooding in north Rapid City and the Rushmore Mall.

Thunderstorm Wind in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:20:00 to 14-AUG-17 17:20:00 (MST-7)
Location: RAPID CITY
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

The spotter reported wind gusts at least 60 mph.

Thunderstorm Wind in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 16:57:00 to 14-AUG-17 16:59:00 (MST-7)
Location: RAPID CITY
Magnitude: 57.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:00:00 to 14-AUG-17 17:00:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:05:00 to 14-AUG-17 17:05:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:09:00 to 14-AUG-17 17:09:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:09:00 to 14-AUG-17 17:09:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:15:00 to 14-AUG-17 17:20:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Public

Hail in MEADE, SOUTH DAKOTA
From 14-AUG-17 16:45:00 to 14-AUG-17 16:45:00 (MST-7)
Location: BLACK HAWK
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:13:00 to 14-AUG-17 17:13:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 17:05:00 to 14-AUG-17 17:05:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

The storm also produced wind gusts around 55 mph and torrential rain.

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 16:24:00 to 14-AUG-17 16:24:00 (MST-7)
Location: JOHNSON SIDING
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in PENNINGTON, SOUTH DAKOTA
From 14-AUG-17 16:47:00 to 14-AUG-17 16:47:00 (MST-7)
Location: HISEGA
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: Public