A large, long-lived supercell thunderstorm tracked from the Spearfish area across the central Black Hills and then southeast through Oglala Lakota County before moving into Nebraska. The storm produced a swath of large hail and strong wind gusts in its path. The most significant damage was in the Oglala area, where hail larger than baseball size damaged several hundred homes. Large hail and strong winds also caused property damage just west of Spearfish.

Thunderstorm Wind in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:28:00 to 27-JUL-18 15:28:00 (MST-7)
Location: SPEARFISH
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated near 60 mph.

Hail in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:30:00 to 27-JUL-18 15:30:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:31:00 to 27-JUL-18 15:31:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:34:00 to 27-JUL-18 15:34:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:37:00 to 27-JUL-18 15:37:00 (MST-7)
Location: SPEARFISH
Magnitude: 51.00 MG
Crop damage: 0.00K
Reported by: Mesonet

Hail in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:25:00 to 27-JUL-18 15:25:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Trained Spotter

The combination of large hail and gusty winds broke windows in a home and vehicles.

Hail in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:28:00 to 27-JUL-18 15:28:00 (MST-7)
Location: SPEARFISH
Magnitude: 1.25 
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in CUSTER, SOUTH DAKOTA
From 27-JUL-18 17:41:00 to 27-JUL-18 17:41:00 (MST-7)
Location: FAIRBURN
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated at 70 mph.

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:33:00 to 27-JUL-18 18:33:00 (MST-7)
Location: OGLALA
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Emergency Manager

Wind gusts were estimated at 60 to 70 mph.

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:04:00 to 27-JUL-18 18:04:00 (MST-7)
Location: RED SHIRT
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated at 60 mph.

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:34:00 to 27-JUL-18 18:34:00 (MST-7)
Location: OGLALA
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Large wind-driven hail in the Oglala area damaged at least 300 homes and over 100 vehicles. Minor injuries were reported from broken glass.

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:59:00 to 27-JUL-18 18:59:00 (MST-7)
Location: PINE RIDGE
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated near 70 mph.

Thunderstorm Wind in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:34:00 to 27-JUL-18 18:34:00 (MST-7)
Location: OGLALA
Magnitude: 52.00 EG
Crop damage: 0.00K
Reported by: Trained Spotter

Wind gusts were estimated at 60 mph.

Hail in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 16:05:00 to 27-JUL-18 16:05:00 (MST-7)
Location: DEADWOOD
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in LAWRENCE, SOUTH DAKOTA
From 27-JUL-18 15:38:00 to 27-JUL-18 15:43:00 (MST-7)
Location: SPEARFISH
Magnitude: 61.00 EG
Crop damage: 0.00K
Reported by: Law Enforcement

Many trees were blown down in Spearfish Canyon along US Highway 14A from Cleopatra Lane to around two miles south.

Thunderstorm Wind in PENNINGTON, SOUTH DAKOTA
From 27-JUL-18 16:23:00 to 27-JUL-18 16:23:00 (MST-7)
Location: SILVER CITY
Magnitude: 50.00 MG
Crop damage: 0.00K
Reported by: Mesonet

Hail in PENNINGTON, SOUTH DAKOTA
From 27-JUL-18 16:27:00 to 27-JUL-18 16:27:00 (MST-7)
Location: SILVER CITY
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CUSTER, SOUTH DAKOTA
From 27-JUL-18 17:11:00 to 27-JUL-18 17:11:00 (MST-7)
Location: HERMOSA
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: NWS Employee

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:35:00 to 27-JUL-18 18:35:00 (MST-7)
Location: OGLALA
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: Public

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:46:00 to 27-JUL-18 18:46:00 (MST-7)
Location: OGLALA
Magnitude: 3.25 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:51:00 to 27-JUL-18 18:51:00 (MST-7)
Location: PINE RIDGE
Magnitude: 1.50 
Crop damage: 0.00K
Reported by: Public

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:55:00 to 27-JUL-18 18:55:00 (MST-7)
Location: PINE RIDGE
Magnitude: 1.75 
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OGLALA LAKOTA, SOUTH DAKOTA
From 27-JUL-18 18:59:00 to 27-JUL-18 18:59:00 (MST-7)
Location: PINE RIDGE
Magnitude: 1.00 
Crop damage: 0.00K
Reported by: Trained Spotter