A very unstable airmass led to a widespread outbreak of severe weather during the afternoon hours. Hail the size of golf balls and wind gusts in excess of 60 mph was reported. Power outages occurred in many cities as numerous trees and power lines were blown down by storm winds. Heavy rain was also reported.

Thunderstorm Wind in MEAGHER, MONTANA
From 06-JUL-09 15:20:00 to 06-JUL-09 15:20:00 (MST-7)
Location: WHITE SULPHUR SPGS
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 61 mph at White Sulphur Springs 40NW.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 06-JUL-09 15:55:00 to 06-JUL-09 15:55:00 (MST-7)
Location: GERALDINE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 60 mph at Geraldine 1NNE.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 06-JUL-09 15:55:00 to 06-JUL-09 15:55:00 (MST-7)
Location: FT BENTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 60 mph at Fort Benton 30WNW (the Knees).

Thunderstorm Wind in CHOUTEAU, MONTANA
From 06-JUL-09 16:56:00 to 06-JUL-09 16:56:00 (MST-7)
Location: BIG SANDY
Magnitude: 74.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A thunderstorm produced a wind gust to 85 mph at Big Sandy.

Thunderstorm Wind in JUDITH BASIN, MONTANA
From 06-JUL-09 17:30:00 to 06-JUL-09 17:30:00 (MST-7)
Location: GEYSER
Magnitude: 70.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A thunderstorm produced a wind gust to 70 mph at Geyser.

Thunderstorm Wind in FERGUS, MONTANA
From 06-JUL-09 17:31:00 to 06-JUL-09 17:31:00 (MST-7)
Location: ROY
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A thunderstorm produced a wind gust to 59 mph at Roy 2E.

Hail in JEFFERSON, MONTANA
From 06-JUL-09 12:58:00 to 06-JUL-09 12:58:00 (MST-7)
Location: BASIN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at Basin.

Hail in JEFFERSON, MONTANA
From 06-JUL-09 14:45:00 to 06-JUL-09 14:45:00 (MST-7)
Location: CLANCY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at Clancy 1N.

Hail in LEWIS AND CLARK, MONTANA
From 06-JUL-09 14:45:00 to 06-JUL-09 14:45:00 (MST-7)
Location: MARYSVILLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at Marysville 6ESE.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 06-JUL-09 15:00:00 to 06-JUL-09 15:00:00 (MST-7)
Location: FT BENTON
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 60 mph at Fort Benton 9S.

Hail in CASCADE, MONTANA
From 06-JUL-09 15:00:00 to 06-JUL-09 15:00:00 (MST-7)
Location: MONARCH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1.75 inch diameter hail at Monarch 3S.

Hail in JUDITH BASIN, MONTANA
From 06-JUL-09 15:08:00 to 06-JUL-09 15:08:00 (MST-7)
Location: GEYSER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

A thunderstorm dropped 1 inch diameter hail at Geyser 6ENE.

Hail in MEAGHER, MONTANA
From 06-JUL-09 15:30:00 to 06-JUL-09 15:30:00 (MST-7)
Location: WHITE SULPHUR SPGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1 inch diameter hail at White Sulphur Springs 33WNW.

Hail in LEWIS AND CLARK, MONTANA
From 06-JUL-09 13:47:00 to 06-JUL-09 13:47:00 (MST-7)
Location: CANYON CREEK
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm dropped 1.75 inch diameter hail at Canyon Creek 7SE.

Thunderstorm Wind in CHOUTEAU, MONTANA
From 06-JUL-09 16:00:00 to 06-JUL-09 16:00:00 (MST-7)
Location: FT BENTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 60 mph at Fort Benton. The storm downed tree limbs 3 to 4 inches in diameter and caused numerous power outages.

Thunderstorm Wind in HILL, MONTANA
From 06-JUL-09 16:56:00 to 06-JUL-09 16:56:00 (MST-7)
Location: INVERNESS
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

A thunderstorm produced a wind gust to 70 mph at Inverness 2E (the Inverness DOT site).

Hail in HILL, MONTANA
From 06-JUL-09 17:30:00 to 06-JUL-09 17:30:00 (MST-7)
Location: HAVRE
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A thunderstorm dropped 1.75 inch diameter hail at Havre 4SW. The hail broke a vehicle's windshield.

Thunderstorm Wind in HILL, MONTANA
From 06-JUL-09 17:38:00 to 06-JUL-09 17:38:00 (MST-7)
Location: HAVRE
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

A thunderstorm produced a wind gust to 59 mph at Havre 4W (the Havre ASOS site).

Thunderstorm Wind in CHOUTEAU, MONTANA
From 06-JUL-09 16:22:00 to 06-JUL-09 16:22:00 (MST-7)
Location: FT BENTON
Magnitude: 51.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A thunderstorm produced a wind gust to 59 mph at Fort Benton 1NE.

Thunderstorm Wind in LIBERTY, MONTANA
From 06-JUL-09 16:50:00 to 06-JUL-09 16:50:00 (MST-7)
Location: CHESTER
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 67 mph at Chester 7SE.

Thunderstorm Wind in TETON, MONTANA
From 06-JUL-09 15:00:00 to 06-JUL-09 15:00:00 (MST-7)
Location: CHOTEAU
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A thunderstorm produced a wind gust to 60 mph at Choteau.