A long-lived supercell thunderstorm tracked from northeastern Wyoming, across the northern Black Hills, and to Bennett County before moving into Nebraska. The storm brought a swath of very large hail and strong wind gusts from south of Spearfish, to the Rapid City area, and across portions of the west central and southwestern South Dakota plains. The storm produced two tornadoes; one across the northern Black Hills and the other over western Bennett County.

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:33:00 to 10-JUL-20 15:48:00 (MST-7)
Location: RAPID CITY
Magnitude: 2.25 
Crop damage: 0.00K
Reported by: Official NWS Observations

Hail in LAWRENCE, SOUTH DAKOTA
From 10-JUL-20 14:40:00 to 10-JUL-20 14:40:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in LAWRENCE, SOUTH DAKOTA
From 10-JUL-20 14:45:00 to 10-JUL-20 14:45:00 (MST-7)
Location: CHEYENNE CROSSING
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: 911 Call Center

Power lines and trees were downed over US Highway 14A between Cheyenne Crossing and Savoy.

Hail in LAWRENCE, SOUTH DAKOTA
From 10-JUL-20 14:45:00 to 10-JUL-20 14:45:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LAWRENCE, SOUTH DAKOTA
From 10-JUL-20 14:51:00 to 10-JUL-20 14:51:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Public

Hail in MEADE, SOUTH DAKOTA
From 10-JUL-20 15:20:00 to 10-JUL-20 15:30:00 (MST-7)
Location: PIEDMONT
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in MEADE, SOUTH DAKOTA
From 10-JUL-20 15:24:00 to 10-JUL-20 15:24:00 (MST-7)
Location: PIEDMONT
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in MEADE, SOUTH DAKOTA
From 10-JUL-20 15:30:00 to 10-JUL-20 15:30:00 (MST-7)
Location: BLACK HAWK
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MEADE, SOUTH DAKOTA
From 10-JUL-20 15:30:00 to 10-JUL-20 15:30:00 (MST-7)
Location: BLACK HAWK
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated at 60 mph.

Hail in MEADE, SOUTH DAKOTA
From 10-JUL-20 15:34:00 to 10-JUL-20 15:34:00 (MST-7)
Location: BLACK HAWK
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:20:00 to 10-JUL-20 15:20:00 (MST-7)
Location: JOHNSON SIDING
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:20:00 to 10-JUL-20 15:20:00 (MST-7)
Location: JOHNSON SIDING
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

The spotter estimated wind gusts around 60 mph.

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:30:00 to 10-JUL-20 15:30:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Public

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:35:00 to 10-JUL-20 15:35:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.25 
Crop damage: 0.00K
Reported by: Official NWS Observations

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:35:00 to 10-JUL-20 15:35:00 (MST-7)
Location: RAPID CITY
Magnitude: 3.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:36:00 to 10-JUL-20 15:36:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:40:00 to 10-JUL-20 15:53:00 (MST-7)
Location: RAPID CITY
Magnitude: 3.25 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:40:00 to 10-JUL-20 15:40:00 (MST-7)
Location: RAPID CITY
Magnitude: 2.50 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:43:00 to 10-JUL-20 15:43:00 (MST-7)
Location: RAPID CITY
Magnitude: 3.00 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:44:00 to 10-JUL-20 15:44:00 (MST-7)
Location: RAPID CITY
Magnitude: 2.00 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:44:00 to 10-JUL-20 15:44:00 (MST-7)
Location: RAPID CITY
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Public

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:46:00 to 10-JUL-20 15:46:00 (MST-7)
Location: RAPID CITY
Magnitude: 2.00 
Crop damage: 0.00K
Reported by: Public

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:48:00 to 10-JUL-20 15:48:00 (MST-7)
Location: RAPID CITY
Magnitude: 2.25 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:50:00 to 10-JUL-20 15:50:00 (MST-7)
Location: ROCKERVILLE
Magnitude: 1.25 
Crop damage: 0.00K
Reported by: CoCoRaHS

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:50:00 to 10-JUL-20 15:50:00 (MST-7)
Location: RAPID CITY
Magnitude: 3.25 
Crop damage: 0.00K
Reported by: Public

Vehicle damage, including several broken windshields, was noted in the neighborhood.

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:51:00 to 10-JUL-20 15:59:00 (MST-7)
Location: ROCKERVILLE
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:53:00 to 10-JUL-20 15:53:00 (MST-7)
Location: (RAP)RAPID CITY ARPT
Magnitude: 1.25 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:54:00 to 10-JUL-20 15:54:00 (MST-7)
Location: RAPID CITY
Magnitude: 3.00 
Crop damage: 0.00K
Reported by: Public

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 15:56:00 to 10-JUL-20 15:56:00 (MST-7)
Location: ROCKERVILLE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 16:00:00 to 10-JUL-20 16:00:00 (MST-7)
Location: RAPID CITY
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 16:30:00 to 10-JUL-20 16:30:00 (MST-7)
Location: FARMINGDALE
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in PENNINGTON, SOUTH DAKOTA
From 10-JUL-20 16:30:00 to 10-JUL-20 16:30:00 (MST-7)
Location: FARMINGDALE
Magnitude: 70.00 EG
Crop damage: 0.00K
Reported by: Public

Wind gusts were estimated at 80 mph.

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 10-JUL-20 16:50:00 to 10-JUL-20 16:50:00 (MST-7)
Location: ROCKYFORD
Magnitude: 2.50 
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 10-JUL-20 17:15:00 to 10-JUL-20 17:15:00 (MST-7)
Location: SHARPS CORNER
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Tribal Official

Extensive roof and structural damage occurred at the Porcupine Dialysis Center, with one minor injury.

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 10-JUL-20 17:25:00 to 10-JUL-20 17:25:00 (MST-7)
Location: SHARPS CORNER
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 10-JUL-20 17:37:00 to 10-JUL-20 17:37:00 (MST-7)
Location: PORCUPINE
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 10-JUL-20 17:37:00 to 10-JUL-20 17:37:00 (MST-7)
Location: PORCUPINE
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

A 40 foot long trailer house was destroyed, outbuildings were damaged, and hay bales rolled a quarter of a mile.

Thunderstorm Wind in BENNETT, SOUTH DAKOTA
From 10-JUL-20 17:49:00 to 10-JUL-20 17:49:00 (MST-7)
Location: SWETT
Magnitude: 70.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

The tops of some trees were snapped off, large trees uprooted, and shingles were missing from structures.

Hail in BENNETT, SOUTH DAKOTA
From 10-JUL-20 17:55:00 to 10-JUL-20 17:55:00 (MST-7)
Location: SWETT
Magnitude: 4.00 
Crop damage: 0.00K
Reported by: Public

Hail in BENNETT, SOUTH DAKOTA
From 10-JUL-20 18:15:00 to 10-JUL-20 18:15:00 (MST-7)
Location: MARTIN
Magnitude: 2.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in TODD, SOUTH DAKOTA
From 10-JUL-20 19:37:00 to 10-JUL-20 19:37:00 (CST-6)
Location: PARMELEE
Magnitude: 50.00 MG
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in TODD, SOUTH DAKOTA
From 10-JUL-20 19:57:00 to 10-JUL-20 20:07:00 (CST-6)
Location: MISSION
Magnitude: 74.00 MG
Crop damage: 0.00K
Reported by: Mesonet

Tornado in LAWRENCE, SOUTH DAKOTA
From 10-JUL-20 14:35:00 to 10-JUL-20 14:59:00 (MST-7)
Location: CHEYENNE CROSSING
Tornado F-scale: EF1
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado tracked across forested terrain of the northern Black Hills for 15.5 miles. Many trees were snapped or uprooted along its path. Although the tornado itself did not cause property damage, trees were blown down onto houses and power lines.

Tornado in BENNETT, SOUTH DAKOTA
From 10-JUL-20 17:42:00 to 10-JUL-20 18:02:00 (MST-7)
Location: SWETT
Tornado F-scale: EF0
Crop damage: 0.00K
Reported by: NWS Storm Survey

An EF1 tornado tracked southeast across areas western Bennett County west and south of Swett. A mobile home was destroyed as it rolled 50 feet from its previous location. A few other homes on the edge of the tornado path were also damaged. Some large trees and branches were downed.