An upper level ridge moved east of Montana during the day bringing southwest flow aloft across eastern Montana. Dewpoints started off low, however a boundary of higher moisture at the surface moved across northeast Montana which became the focus of the intensified convection. The storms began in northern Blaine County then into Phillips County. Better instability allowed the strong storms to become severe as they moved east.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 06-AUG-10 20:52:00 to 06-AUG-10 20:52:00 (MST-7)
Location: MCDONALDS DOT
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in MCCONE, MONTANA
From 06-AUG-10 21:35:00 to 06-AUG-10 21:35:00 (MST-7)
Location: CIRCLE
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Heavy Rain in MCCONE, MONTANA
From 06-AUG-10 21:20:00 to 06-AUG-10 21:30:00 (MST-7)
Location: VIDA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Three inches of water was observed over Highway 528 at mile marker 9.

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 18:30:00 to 06-AUG-10 18:30:00 (MST-7)
Location: HINSDALE
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The wind broke 5 inch branches out of trees.

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 18:40:00 to 06-AUG-10 18:45:00 (MST-7)
Location: HINSDALE
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

At 1840 MST 3 miles east of Hinsdale, a haystack was blown up from the wind gust. At about the same time, a trained spotter estimated a 70 mph wind gust and half inch hail.

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 20:20:00 to 06-AUG-10 20:20:00 (MST-7)
Location: NASHUA
Magnitude: 104.00 EG
Property damage: 0.00K
Crop damage: 750.00K
Reported by: NWS Storm Survey

A macroburst occurred where damage consisted of one doublewide manufactured home with the roof blown off, one empty storage building blown apart, and about 3 miles of downed power lines (approximately 44 poles all together) starting near mile marker 10 north of Nashua on the Nashua Road (State Highway 438). The power poles were snapped cleanly, mostly at ground level. As the poles were around 10 years old and relatively strong looking, and there were 3 miles of snapped poles, the NWS officials estimated the winds to be around 120 mph. The house and storage building had less wind, since nearby poles were not snapped at those locations. This also was the origination point to where a combined swath of hail and wind damaged 70 to 100 percent of the crops east southeast to the Roosevelt County border. This storm continued into extreme southwest Roosevelt County.
According to the USDA Hazard Risk Assessment indemnity figures, approximately $750,000 worth of crop damage occurred with this storm (as of October 12, 2010).

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 19:23:00 to 06-AUG-10 19:23:00 (MST-7)
Location: GLASGOW
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in ROOSEVELT, MONTANA
From 06-AUG-10 20:50:00 to 06-AUG-10 20:50:00 (MST-7)
Location: WOLF PT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This storm was part of a hail and wind swath that mainly affected southeast Valley County, moved east-southeast and ended near this point.

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 20:00:00 to 06-AUG-10 20:00:00 (MST-7)
Location: GLASGOW
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.75M
Reported by: NWS Employee

NWS Survey team witnessed over 20,000 acres of crops 70 to 100% destroyed from the wind and nickel size hail. This was part of the hail/wind swath that extended from 12 miles north of Nashua to the southwest portion of Roosevelt County.

Thunderstorm Wind in MCCONE, MONTANA
From 06-AUG-10 21:25:00 to 06-AUG-10 21:25:00 (MST-7)
Location: VIDA
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Pea size hail also fell.

Hail in PHILLIPS, MONTANA
From 06-AUG-10 17:41:00 to 06-AUG-10 17:41:00 (MST-7)
Location: SACO
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 0.25 also fell.

Hail in PHILLIPS, MONTANA
From 06-AUG-10 17:48:00 to 06-AUG-10 17:48:00 (MST-7)
Location: SACO
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail was covering the ground.

Hail in PHILLIPS, MONTANA
From 06-AUG-10 17:53:00 to 06-AUG-10 17:53:00 (MST-7)
Location: SACO
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in PHILLIPS, MONTANA
From 06-AUG-10 18:17:00 to 06-AUG-10 18:17:00 (MST-7)
Location: SACO
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Rainfall of 0.50 also fell.

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 19:37:00 to 06-AUG-10 19:37:00 (MST-7)
Location: GLASGOW INTL AIRPORT (KGGW)
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Hail in ROOSEVELT, MONTANA
From 06-AUG-10 21:00:00 to 06-AUG-10 21:00:00 (MST-7)
Location: WOLF PT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in VALLEY, MONTANA
From 06-AUG-10 19:18:00 to 06-AUG-10 19:23:00 (MST-7)
Location: GLASGOW
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

NWS Employee estimated wind gust at 2 miles west of Glasgow. Public estimated wind gust 7 miles north of Glasgow.