A quick-moving low pressure disturbance from the southwest interacted with a warm front and a very unstable atmosphere to develop and sustain multiple long-track severe thunderstorms and some flash flooding.

Hail in WIBAUX, MONTANA
From 08-JUN-21 17:50:00 to 08-JUN-21 17:50:00 (MST-7)
Location: ST PHILLIP
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public posted photos of, and reported ping pong ball size hail, via Facebook.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 08-JUN-21 20:10:00 to 08-JUN-21 20:10:00 (MST-7)
Location: WOLF PT INTL AIRPORT(KOLF)
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 60 mph thunderstorm wind gusts.

Thunderstorm Wind in PHILLIPS, MONTANA
From 08-JUN-21 18:00:00 to 08-JUN-21 18:00:00 (MST-7)
Location: SACO
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 60 mph wind and pea size hail.

Thunderstorm Wind in VALLEY, MONTANA
From 08-JUN-21 20:44:00 to 08-JUN-21 20:44:00 (MST-7)
Location: BLUFF CREEK RAWS
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Bluff Creek RAWS site (BLUM8) recorded a 58 mph thunderstorm wind gust.  Time estimated.

Thunderstorm Wind in RICHLAND, MONTANA
From 08-JUN-21 21:10:00 to 08-JUN-21 21:10:00 (MST-7)
Location: SIDNEY
Magnitude: 73.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported an 84 mph thunderstorm wind gust, measured on their home weather station.

Thunderstorm Wind in RICHLAND, MONTANA
From 08-JUN-21 21:15:00 to 08-JUN-21 21:15:00 (MST-7)
Location: SIDNEY AIRPORT (KSDY)
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

The Sidney airport AWOS site (KSDY), measured a 61 mph thunderstorm wind gust.

Thunderstorm Wind in RICHLAND, MONTANA
From 08-JUN-21 21:17:00 to 08-JUN-21 21:17:00 (MST-7)
Location: SIDNEY
Magnitude: 67.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

An NDAWN mesonet site located 1 NNE Sidney measured a 77 mph thunderstorm wind gust.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 08-JUN-21 21:30:00 to 08-JUN-21 21:30:00 (MST-7)
Location: BAINVILLE
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported a thunderstorm wind gust of 60 mph.  Time estimated.

Hail in GARFIELD, MONTANA
From 08-JUN-21 18:15:00 to 08-JUN-21 18:15:00 (MST-7)
Location: JORDAN AIRPORT (KJDN)
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported golf ball size hail.

Hail in VALLEY, MONTANA
From 08-JUN-21 18:16:00 to 08-JUN-21 18:16:00 (MST-7)
Location: OSWEGO
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported golf ball sized hail.

Hail in GARFIELD, MONTANA
From 08-JUN-21 19:00:00 to 08-JUN-21 19:00:00 (MST-7)
Location: COHAGEN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported hail up to the size of quarters.

Hail in GARFIELD, MONTANA
From 08-JUN-21 19:00:00 to 08-JUN-21 19:00:00 (MST-7)
Location: VAN NORMAN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported golf ball size hail.

Hail in ROOSEVELT, MONTANA
From 08-JUN-21 20:10:00 to 08-JUN-21 20:10:00 (MST-7)
Location: WOLF PT INTL AIRPORT(KOLF)
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported quarter size hail.

Thunderstorm Wind in PHILLIPS, MONTANA
From 08-JUN-21 18:15:00 to 08-JUN-21 18:15:00 (MST-7)
Location: SACO
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported 70 mph wind and up to 0.70 inch rainfall.

Thunderstorm Wind in RICHLAND, MONTANA
From 08-JUN-21 18:23:00 to 08-JUN-21 18:23:00 (MST-7)
Location: SIDNEY AIRPORT (KSDY)
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Sidney airport ASOS site (KSDY) recorded at 61 mph thunderstorm wind gust.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 08-JUN-21 18:54:00 to 08-JUN-21 18:56:00 (MST-7)
Location: WOLF PT INTL AIRPORT(KOLF)
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Wolf Point airport ASOS site (KOLF), recorded thunderstorm wind gusts of 59 to 64 mph over these two minutes.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 08-JUN-21 19:03:00 to 08-JUN-21 19:03:00 (MST-7)
Location: WOLF PT INTL AIRPORT(KOLF)
Magnitude: 75.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported an 86 mph thunderstorm wind gust, along with heavy rain and small hail.

Thunderstorm Wind in MCCONE, MONTANA
From 08-JUN-21 19:15:00 to 08-JUN-21 19:15:00 (MST-7)
Location: WELDON
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported a 60 mph thunderstorm wind gust along with nickel size hail.

Hail in ROOSEVELT, MONTANA
From 08-JUN-21 11:30:00 to 08-JUN-21 11:30:00 (MST-7)
Location: FT KIPP
Magnitude: 1.30 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter measured half dollar size hail.

Hail in RICHLAND, MONTANA
From 08-JUN-21 13:46:00 to 08-JUN-21 13:46:00 (MST-7)
Location: SIOUX PASS DOT
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported hen egg size hail.

Flash Flood in ROOSEVELT, MONTANA
From 08-JUN-21 19:20:00 to 08-JUN-21 19:30:00 (MST-7)
Location: WOLF PT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Multiple reports from public and Roosevelt County Emergency Manager of water up to one  foot high flowing over US-Highway 2 including rocks and debris.

Flash Flood in ROOSEVELT, MONTANA
From 08-JUN-21 19:35:00 to 08-JUN-21 20:10:00 (MST-7)
Location: WOLF PT INTL AIRPORT(KOLF)
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Multiple reports of water flooding over MT-Highway 13, about 7 miles NE of Wolf Point, near mile marker 12, in an area of deep coulees.  Some back roads were also washed out.   A rancher in the area said he had never seen water over the road in these locations in his 85 years.

Heavy Rain in ROOSEVELT, MONTANA
From 08-JUN-21 20:10:00 to 08-JUN-21 20:10:00 (MST-7)
Location: WOLF PT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter measured 3.00 inches of rainfall.

Thunderstorm Wind in ROOSEVELT, MONTANA
From 08-JUN-21 19:55:00 to 08-JUN-21 19:55:00 (MST-7)
Location: BREDETTE
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported wind damage to their home. A few shingles were blown off and the soffit was broke loose.  Time is estimated.

Thunderstorm Wind in RICHLAND, MONTANA
From 08-JUN-21 21:15:00 to 08-JUN-21 21:15:00 (MST-7)
Location: FAIRVIEW
Magnitude: 80.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Straight-line winds blew through the town of Fairview.  Photos showed large spruce and cottonwood trees uprooted, a metal building caved in and large tree branches down.

Hail in DAWSON, MONTANA
From 08-JUN-21 15:49:00 to 08-JUN-21 15:49:00 (MST-7)
Location: INTAKE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public measured ping pong ball size hail and reported via Facebook.

Hail in WIBAUX, MONTANA
From 08-JUN-21 15:50:00 to 08-JUN-21 15:50:00 (MST-7)
Location: BEAVER HILL DOT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter estimated quarter size hail bouncing off the ground.

Thunderstorm Wind in VALLEY, MONTANA
From 08-JUN-21 19:20:00 to 08-JUN-21 19:20:00 (MST-7)
Location: SAINT MARIE
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

The Saint Marie mesonet site (07MT) measured a 58 mph thunderstorm wind gust.

Thunderstorm Wind in MCCONE, MONTANA
From 08-JUN-21 18:55:00 to 08-JUN-21 19:40:00 (MST-7)
Location: WELDON
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

McCone County Emergency Manager reported 60 mph thunderstorm wind gusts for a 45 minute period, along with heavy rain and some lowland nuisance flooding.

Hail in DAWSON, MONTANA
From 08-JUN-21 16:00:00 to 08-JUN-21 16:00:00 (MST-7)
Location: GLENDIVE
Magnitude: 4.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public reported multiple sizes of hail stones via Facebook.  The largest hail stone size of softball was measured.

Thunderstorm Wind in DAWSON, MONTANA
From 08-JUN-21 15:56:00 to 08-JUN-21 15:57:00 (MST-7)
Location: BEAVER HILL DOT
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Beaver Hill I-94 DOT site (MTBVR) measured thunderstorm wind gusts of 68 mph from 3:56 PM MST to 3:57 PM MST.

Hail in WIBAUX, MONTANA
From 08-JUN-21 16:35:00 to 08-JUN-21 16:35:00 (MST-7)
Location: BEAVER HILL DOT
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Wibaux County Fire Department employee reported baseball size hail.

Hail in RICHLAND, MONTANA
From 08-JUN-21 17:00:00 to 08-JUN-21 17:00:00 (MST-7)
Location: SIOUX PASS DOT
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public reported hen egg size hail.

Hail in WIBAUX, MONTANA
From 08-JUN-21 17:05:00 to 08-JUN-21 17:05:00 (MST-7)
Location: BEAVER HILL DOT
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Trained spotter shared their report of measured baseball size hail via Twitter.

Hail in RICHLAND, MONTANA
From 08-JUN-21 17:18:00 to 08-JUN-21 17:18:00 (MST-7)
Location: SIOUX PASS DOT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported golf ball size hail.

Hail in GARFIELD, MONTANA
From 08-JUN-21 17:30:00 to 08-JUN-21 18:15:00 (MST-7)
Location: JORDAN AIRPORT (KJDN)
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotter reported golf ball to tennis ball size hail intermittently during these 45 minutes.

Hail in ROOSEVELT, MONTANA
From 08-JUN-21 17:35:00 to 08-JUN-21 17:35:00 (MST-7)
Location: FT KIPP
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Public posted photos of and reported golf ball size hail, via Facebook.

Thunderstorm Wind in VALLEY, MONTANA
From 08-JUN-21 18:53:00 to 08-JUN-21 18:53:00 (MST-7)
Location: GLASGOW INTL AIRPORT (KGGW)
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

The Glasgow airport ASOS site (KGGW) recorded a 71 mph thunderstorm wind gust.