An intense squall line developed over portions of South Central Montana just east of Billings and pushed across the southeast portions of the state. Large hail and damaging winds accompanied this squall line.

Hail in YELLOWSTONE, MONTANA
From 11-AUG-11 14:58:00 to 11-AUG-11 14:58:00 (MST-7)
Location: BALLANTINE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Thunderstorm Wind in BIG HORN, MONTANA
From 11-AUG-11 15:46:00 to 11-AUG-11 15:46:00 (MST-7)
Location: HARDIN
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A large tree was downed in town.

Thunderstorm Wind in BIG HORN, MONTANA
From 11-AUG-11 15:46:00 to 11-AUG-11 15:46:00 (MST-7)
Location: HARDIN
Magnitude: 65.00 EG
Reported by: NWS Storm Survey

Winds were estimated at 75 mph and were accompanied by dime size hail. One home had several windows broken due to flying debris and hail. Several large tree limbs, as well as three power poles were downed. In addition, 300 acres of sugar beet crop were destroyed. There were also numerous vehicles on the highway that had broken windows.

Thunderstorm Wind in CUSTER, MONTANA
From 11-AUG-11 16:20:00 to 11-AUG-11 16:20:00 (MST-7)
Location: ISMAY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds were estimated at 60-70 mph accompanied by half inch hail. Large trees were missing limbs and leaves.

Thunderstorm Wind in BIG HORN, MONTANA
From 11-AUG-11 16:30:00 to 11-AUG-11 16:30:00 (MST-7)
Location: DECKER
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Winds were estimated at 60 mph. Trees limbs were broken and leaves stripped.

Thunderstorm Wind in POWDER RIVER, MONTANA
From 11-AUG-11 17:08:00 to 11-AUG-11 17:08:00 (MST-7)
Location: SONNETTE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

An estimated wind gust of 60 mph along with dime size hail was reported.

Thunderstorm Wind in POWDER RIVER, MONTANA
From 11-AUG-11 17:45:00 to 11-AUG-11 17:45:00 (MST-7)
Location: BROADUS
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A wind gust estimated at 60 mph was reported in Broadus.

Hail in CARTER, MONTANA
From 11-AUG-11 18:30:00 to 11-AUG-11 18:30:00 (MST-7)
Location: ALZADA
Magnitude: 1.00 
Reported by: Trained Spotter

Winds estimated at 50-60 mph were also reported.

Hail in BIG HORN, MONTANA
From 11-AUG-11 16:20:00 to 11-AUG-11 16:20:00 (MST-7)
Location: KUEHN
Magnitude: 1.00 
Reported by: Trained Spotter

Estimated winds of 50 mph combined with the hail resulted in broken windows. The hail accumulated 6-8 inches deep.

Thunderstorm Wind in CARTER, MONTANA
From 11-AUG-11 18:15:00 to 11-AUG-11 18:15:00 (MST-7)
Location: BOYES
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

An estimated wind gust of 60 mph was reported. The strong winds broke twigs and snapped 2 inch diameter branches off of trees.

Hail in YELLOWSTONE, MONTANA
From 11-AUG-11 14:55:00 to 11-AUG-11 14:55:00 (MST-7)
Location: WORDEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter