A supercell thunderstorm developed near Nemo and moved southeastward across the Rapid City area and into southwestern South Dakota. The storm produced large hail and eventually strong wind gusts as it moved across southwestern South Dakota.

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:22:00 to 07-AUG-11 13:35:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Property damage: 500.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in LAWRENCE, SOUTH DAKOTA
From 07-AUG-11 11:30:00 to 07-AUG-11 11:45:00 (MST-7)
Location: NEMO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 12:10:00 to 07-AUG-11 12:10:00 (MST-7)
Location: JOHNSON SIDING
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 12:15:00 to 07-AUG-11 12:35:00 (MST-7)
Location: JOHNSON SIDING
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Quarter sized hail covered the ground.

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:00:00 to 07-AUG-11 13:00:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.50 
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Public

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:02:00 to 07-AUG-11 13:02:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:13:00 to 07-AUG-11 13:15:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Property damage: 750.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:15:00 to 07-AUG-11 13:15:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Property damage: 500.00K
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:22:00 to 07-AUG-11 13:22:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 07-AUG-11 13:30:00 to 07-AUG-11 13:30:00 (MST-7)
Location: ROCKERVILLE
Magnitude: 2.75 
Property damage: 500.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Vehicles and buildings were damaged by baseball sized hail.

Hail in CUSTER, SOUTH DAKOTA
From 07-AUG-11 14:10:00 to 07-AUG-11 14:15:00 (MST-7)
Location: HERMOSA
Magnitude: 1.50 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, SOUTH DAKOTA
From 07-AUG-11 14:30:00 to 07-AUG-11 14:30:00 (MST-7)
Location: HERMOSA
Magnitude: 1.50 
Property damage: 20.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in CUSTER, SOUTH DAKOTA
From 07-AUG-11 14:30:00 to 07-AUG-11 14:30:00 (MST-7)
Location: HERMOSA
Magnitude: 2.00 
Property damage: 400.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in CUSTER, SOUTH DAKOTA
From 07-AUG-11 15:20:00 to 07-AUG-11 15:20:00 (MST-7)
Location: FOLSOM
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, SOUTH DAKOTA
From 07-AUG-11 15:20:00 to 07-AUG-11 15:20:00 (MST-7)
Location: FOLSOM
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 07-AUG-11 15:30:00 to 07-AUG-11 15:30:00 (MST-7)
Location: RED SHIRT
Magnitude: 1.75 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 07-AUG-11 16:15:00 to 07-AUG-11 16:15:00 (MST-7)
Location: SHARPS CORNER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Penny sized hail also fell with the storm.

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 07-AUG-11 16:15:00 to 07-AUG-11 16:15:00 (MST-7)
Location: KYLE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Small tree branches were broken by the wind.

Thunderstorm Wind in BENNETT, SOUTH DAKOTA
From 07-AUG-11 16:40:00 to 07-AUG-11 16:40:00 (MST-7)
Location: SWETT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated at 60 mph.

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 07-AUG-11 16:30:00 to 07-AUG-11 16:40:00 (MST-7)
Location: BATESLAND
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 07-AUG-11 16:30:00 to 07-AUG-11 16:30:00 (MST-7)
Location: PORCUPINE
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: RAWS