Increasing warm air advection ahead of a short wave impulse combined with a moderately unstable and strongly sheared environment to result in severe thunderstorms over much of west and portions of central North Dakota in the evening of the 31st. Severe Thunderstorm Watch number 819 was in effect for this event.

Hail in SLOPE, NORTH DAKOTA
From 31-AUG-11 19:22:00 to 31-AUG-11 19:26:00 (MST-7)
Location: MARMARTH
Magnitude: 1.75 
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Public

The large hail broke windows.

Hail in MCKENZIE, NORTH DAKOTA
From 31-AUG-11 19:25:00 to 31-AUG-11 19:31:00 (MST-7)
Location: FAIRVIEW
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

Hail in BOWMAN, NORTH DAKOTA
From 31-AUG-11 19:40:00 to 31-AUG-11 19:50:00 (MST-7)
Location: RHAME
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in BOWMAN, NORTH DAKOTA
From 31-AUG-11 19:51:00 to 31-AUG-11 19:56:00 (MST-7)
Location: BOWMAN
Magnitude: 50.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A report of a severe wind gust was received.

Thunderstorm Wind in STARK, NORTH DAKOTA
From 31-AUG-11 20:04:00 to 31-AUG-11 20:09:00 (MST-7)
Location: (DIK)DICKINSON MUNI
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in BOWMAN, NORTH DAKOTA
From 31-AUG-11 20:07:00 to 31-AUG-11 20:14:00 (MST-7)
Location: SCRANTON
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Hail in HETTINGER, NORTH DAKOTA
From 31-AUG-11 20:20:00 to 31-AUG-11 20:24:00 (MST-7)
Location: NEW ENGLAND
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in STARK, NORTH DAKOTA
From 31-AUG-11 20:26:00 to 31-AUG-11 20:31:00 (MST-7)
Location: TAYLOR
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in HETTINGER, NORTH DAKOTA
From 31-AUG-11 20:35:00 to 31-AUG-11 20:37:00 (MST-7)
Location: MOTT
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MOUNTRAIL, NORTH DAKOTA
From 31-AUG-11 21:50:00 to 31-AUG-11 21:55:00 (CST-6)
Location: STANLEY
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Strong winds were reported.

Thunderstorm Wind in STARK, NORTH DAKOTA
From 31-AUG-11 21:00:00 to 31-AUG-11 21:05:00 (MST-7)
Location: ANTELOPE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Pea size hail accompanied the strong winds.

Thunderstorm Wind in MERCER, NORTH DAKOTA
From 31-AUG-11 22:20:00 to 31-AUG-11 22:25:00 (CST-6)
Location: HAZEN
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm Wind in MOUNTRAIL, NORTH DAKOTA
From 31-AUG-11 22:10:00 to 31-AUG-11 22:15:00 (CST-6)
Location: LOSTWOOD
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Strong winds were reported.

Thunderstorm Wind in MCLEAN, NORTH DAKOTA
From 31-AUG-11 22:50:00 to 31-AUG-11 22:55:00 (CST-6)
Location: COLEHARBOR
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 31-AUG-11 22:51:00 to 31-AUG-11 22:57:00 (CST-6)
Location: SWEET BRIAR
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong winds were reported.

Thunderstorm Wind in SHERIDAN, NORTH DAKOTA
From 31-AUG-11 23:13:00 to 31-AUG-11 23:18:00 (CST-6)
Location: MCCLUSKY
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Brief power outages were reported with the strong winds.

Lightning in STARK, NORTH DAKOTA
From 31-AUG-11 19:50:00 to 31-AUG-11 19:50:00 (MST-7)
Location: SOUTH HEART
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Newspaper

A lightning strike triggered a large grass fire near South Heart in western Stark County. The fire also burned around fifty hay bales.

Lightning in SLOPE, NORTH DAKOTA
From 31-AUG-11 19:40:00 to 31-AUG-11 19:40:00 (MST-7)
Location: MARMARTH
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A lightning strike triggered a large grass fire in southern Slope County that burned into the next day. The fire spread through rows of hay bales.

Thunderstorm Wind in WILLIAMS, NORTH DAKOTA
From 31-AUG-11 20:43:00 to 31-AUG-11 20:53:00 (CST-6)
Location: WILLISTON
Magnitude: 53.00 MG
Property damage: 45.00K
Crop damage: 0.00K
Reported by: ASOS

Tree branches were broken off at the Williston airport and a new hanger was damaged.

Thunderstorm Wind in MORTON, NORTH DAKOTA
From 31-AUG-11 22:20:00 to 31-AUG-11 22:28:00 (CST-6)
Location: SIMS
Magnitude: 61.00 EG
Property damage: 65.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Straight line wind damage occurred near New Salem. A barn roof was destroyed, an auger was tipped over, and debris was thrown into the side of a home.

Thunderstorm Wind in MCLEAN, NORTH DAKOTA
From 31-AUG-11 23:00:00 to 31-AUG-11 23:10:00 (CST-6)
Location: MERCER
Magnitude: 61.00 EG
Property damage: 18.00K
Crop damage: 0.00K
Reported by: Public

Several trees were snapped or uprooted.

Thunderstorm Wind in WELLS, NORTH DAKOTA
From 31-AUG-11 23:54:00 to 31-AUG-11 23:59:00 (CST-6)
Location: HARVEY
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Small tree limbs were broken.