Large scale forcing associated with a dynamic upper level trough coincided with very strong deep layer shear and very steep mid level lapse rates to trigger rapid thunderstorm development and intensification across southwest and south central North Dakota. Thunderstorms began in the late evening hours of Tuesday, July 13th, and lasted into the early morning hours of Wednesday, July 14th.
Severe Thunderstorm Watch number 469 was initially issued late Tuesday evening for portions of southwest and most of south central North Dakota through the early morning hours of Wednesday, with rapid thunderstorm development across the southwest already underway. Tornado Watch number 470 was issued early Wednesday morning for far south central North Dakota as intense supercellular thunderstorms with very large hail continued to develop and move east across far southwest and south central parts of the state. The intense thunderstorms eventually transitioned from very large hail producers to damaging wind producers as they moved east of the Missouri River and towards and into the James River Valley region.
Multiple severe thunderstorm and tornado warnings were issued. Numerous reports of large hail, including a record tying hailstone, and several reports of damaging thunderstorm winds were received during this episode.
Damage from the very large hail was extensive and extreme. Hardest hit were Hettinger, Grant, Sioux, and Emmons Counties, where baseball to softball size hail fell. Some homes had hailstones crash completely through the roof. The large hail also killed several farm animals, and injured other livestock and pets. A North Dakota record tying hailstone, five inches in diameter, fell at Prairie Knights Resort located in eastern Sioux County. In addition, some areas in these counties experienced more than one wave of large hail. Later Wednesday morning, straight line winds up to 105 mph resulted in extensive damage over portions of Logan and LaMoure Counties.

Hail in LOGAN, NORTH DAKOTA
From 14-JUL-10 02:09:00 to 14-JUL-10 02:18:00 (CST-6)
Location: NAPOLEON
Magnitude: 2.75 
Property damage: 1.50M
Crop damage: 1.00M
Reported by: Newspaper

The large hail damaged many area homes, campers, and vehicles.  Damage to crops was limited as despite the large size of the hail, the aerial coverage of hail was spotty according to insurance adjusters.

Flash Flood in STUTSMAN, NORTH DAKOTA
From 14-JUL-10 01:10:00 to 14-JUL-10 04:00:00 (CST-6)
Location: STREETER
Flood cause: Heavy Rain
Property damage: 80.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Several low lying areas of County Highway 67 from north of Gackle to Interstate 94 showed signs of recent flash flooding. Water was flowing freely over one area, with severe erosion noted at other low lying areas along the highway.

Hail in SIOUX, NORTH DAKOTA
From 13-JUL-10 22:40:00 to 13-JUL-10 22:55:00 (MST-7)
Location: CANNON BALL
Magnitude: 5.00 
Property damage: 1.50M
Crop damage: 500.00K
Reported by: NWS Storm Survey

A North Dakota state record tying hailstone of five inches in diameter fell at Prairie Knights Casino and Resort. The resort, and all vehicles outside, sustained severe damage from the extreme hail. One of these large hail stones crashed through the windshield of a car, injuring the two occupants. This tied the record size five inch diameter hailstone in Mercer County on August 3, 1969.

Hail in SIOUX, NORTH DAKOTA
From 14-JUL-10 00:21:00 to 14-JUL-10 00:30:00 (MST-7)
Location: CANNON BALL
Magnitude: 4.25 
Property damage: 100.00K
Crop damage: 150.00K
Reported by: Public

This was the second wave of very large hail to impact Cannon Ball during this episode, resulting in further damage to homes, vehicles, and crops.

Hail in SIOUX, NORTH DAKOTA
From 14-JUL-10 01:08:00 to 14-JUL-10 01:15:00 (MST-7)
Location: CANNON BALL
Magnitude: 1.75 
Property damage: 50.00K
Crop damage: 50.00K
Reported by: Public

This was the third wave of large hail to impact the city of Cannon Ball during this episode.

Hail in SIOUX, NORTH DAKOTA
From 14-JUL-10 00:10:00 to 14-JUL-10 00:20:00 (MST-7)
Location: SOLEN
Magnitude: 4.25 
Property damage: 100.00K
Crop damage: 400.00K
Reported by: Public

Damage amounts were estimated based on the extreme hail size.

Lightning in GRANT, NORTH DAKOTA
From 13-JUL-10 23:30:00 to 13-JUL-10 23:30:00 (MST-7)
Location: ELGIN
Property damage: 65.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A lightning strike caused a house fire in Elgin. The lightning bolt struck the chimney of the house, traveling into the basement starting a fire in the electrical wiring on all three levels of the home. When arriving on scene, fire officials reported that a metal antenna on the chimney of the home was glowing bright orange. No injuries or fatalities occurred. The home was determined to be a complete loss.

Hail in SIOUX, NORTH DAKOTA
From 13-JUL-10 23:02:00 to 13-JUL-10 23:10:00 (MST-7)
Location: CANNON BALL
Magnitude: 4.25 
Property damage: 750.00K
Crop damage: 250.00K
Reported by: Public

This was the first of three waves of very large hail to impact the city of Cannon Ball during this episode. Severe damage to vehicles, homes, and crops occurred.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 01:55:00 to 14-JUL-10 02:10:00 (CST-6)
Location: EDGELEY
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 50.00K
Reported by: NWS Storm Survey

Corn fields across central LaMoure County were flattened by strong thunderstorm winds. Local residents were unsure if the corn was a partial or complete loss.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 01:55:00 to 14-JUL-10 02:10:00 (CST-6)
Location: NORTONVILLE
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 50.00K
Reported by: NWS Storm Survey

Corn fields across central LaMoure County were flattened by strong thunderstorm winds. Local residents were unsure if the corn was a partial or complete loss.

Thunderstorm Wind in LOGAN, NORTH DAKOTA
From 14-JUL-10 01:40:00 to 14-JUL-10 01:50:00 (CST-6)
Location: GACKLE
Magnitude: 65.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The severe thunderstorm winds blew down numerous tree branches, including one tree snapped off on the west side of Gackle.  Other wind damage included a flag pole bent over and a television antenna blown off of a roof.

Thunderstorm Wind in LOGAN, NORTH DAKOTA
From 14-JUL-10 01:40:00 to 14-JUL-10 01:50:00 (CST-6)
Location: FREDONIA
Magnitude: 70.00 EG
Property damage: 35.00K
Crop damage: 0.00K
Reported by: Mesonet

A kill chute weighing about 1500 pounds was blown over. The strong thunderstorm winds also tore shingles off of a roof.

Hail in EMMONS, NORTH DAKOTA
From 14-JUL-10 00:15:00 to 14-JUL-10 00:25:00 (CST-6)
Location: LINTON
Magnitude: 2.50 
Property damage: 500.00K
Crop damage: 650.00K
Reported by: Newspaper

Damage was sustained to area homes and vehicles. Crop damage was reported to be severe across central Emmons County.

Hail in HETTINGER, NORTH DAKOTA
From 13-JUL-10 21:15:00 to 13-JUL-10 21:23:00 (MST-7)
Location: BURT
Magnitude: 1.75 
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong winds accompanied the large hail.  The large hail resulted in damage to siding on a garage.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 21:30:00 to 13-JUL-10 21:41:00 (MST-7)
Location: NEW LEIPZIG
Magnitude: 2.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Specific damage estimates from the large hail were not available. This was the first wave of large hail for New Leipzig during this episode.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 21:33:00 to 13-JUL-10 21:43:00 (MST-7)
Location: ELGIN
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Specific damage estimates from the large hail were not available. This was the first wave of large hail in Elgin for this episode.

Thunderstorm Wind in GRANT, NORTH DAKOTA
From 13-JUL-10 21:33:00 to 13-JUL-10 21:43:00 (MST-7)
Location: ELGIN
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Strong thunderstorm winds accompanied the large hail.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:00:00 to 13-JUL-10 22:11:00 (MST-7)
Location: RALEIGH
Magnitude: 1.50 
Property damage: 25.00K
Crop damage: 50.00K
Reported by: Trained Spotter

Strong thunderstorm winds accompanied the large hail, and resulted in windows on the west side of a house broken.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:00:00 to 13-JUL-10 22:10:00 (MST-7)
Location: BRISBANE
Magnitude: 1.50 
Property damage: 15.00K
Crop damage: 50.00K
Reported by: Public

The large hail resulted in two skylights and one window broken.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:05:00 to 13-JUL-10 22:15:00 (MST-7)
Location: RALEIGH
Magnitude: 1.50 
Property damage: 45.00K
Crop damage: 50.00K
Reported by: Trained Spotter

The large hail resulted in damaged vehicles at the Prairie Learning Center in Saint Gertrude.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:08:00 to 13-JUL-10 22:16:00 (MST-7)
Location: RALEIGH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 50.00K
Reported by: Emergency Manager

Hail in HETTINGER, NORTH DAKOTA
From 13-JUL-10 22:08:00 to 13-JUL-10 22:16:00 (MST-7)
Location: REGENT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in BOWMAN, NORTH DAKOTA
From 13-JUL-10 22:09:00 to 13-JUL-10 22:19:00 (MST-7)
Location: BOWMAN
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 50.00K
Reported by: Emergency Manager

Hail in BOWMAN, NORTH DAKOTA
From 13-JUL-10 22:20:00 to 13-JUL-10 22:29:00 (MST-7)
Location: RHAME
Magnitude: 1.75 
Property damage: 2.00K
Crop damage: 150.00K
Reported by: Emergency Manager

The large hail broke out the windsheild on a truck.

Hail in HETTINGER, NORTH DAKOTA
From 13-JUL-10 22:22:00 to 13-JUL-10 22:32:00 (MST-7)
Location: MOTT
Magnitude: 2.75 
Property damage: 750.00K
Crop damage: 500.00K
Reported by: Emergency Manager

County officials reported up to baseball size hail in Mott. All vehicles left outside received major damage. The north side of homes sustained siding damage and broken windows. Roofs were also damaged from the large hail.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:24:00 to 13-JUL-10 22:34:00 (MST-7)
Location: RALEIGH
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 250.00K
Reported by: Public

Specific damage estimates from the large hail were not available.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 02:02:00 to 14-JUL-10 02:13:00 (CST-6)
Location: GRAND RAPIDS
Magnitude: 78.00 EG
Property damage: 60.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Intense straight line thunderstorm winds damaged outbuildings on a farmstead just west of Grand Rapids. The roof on a barn was partially ripped off and a flag pole was bent over.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 02:04:00 to 14-JUL-10 02:15:00 (CST-6)
Location: GRAND RAPIDS
Magnitude: 91.00 EG
Property damage: 650.00K
Crop damage: 50.00K
Reported by: NWS Storm Survey

The most severe wind damage observed during the storm survey in LaMoure County occurred in the town of Grand Rapids. Significant and widespread tree damage was observed, including numerous mature hardwood trees uprooted or snapped in half. Damage was also sustained to buildings, which consisted of roof damage, damage to pole barns, and several grain bins destroyed. Hey bales of 1300 pounds were also blown up to 500 yards across farm fields.
The peak estimated wind speed of 105 mph was assigned based on damage indicators from the Enhanced Fujita Scale. It was later learned that wind sensing instruments on wind towers 10 miles west of Edgeley recorded a peak wind gust of 103 mph during the storm.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 02:07:00 to 14-JUL-10 02:18:00 (CST-6)
Location: GRAND RAPIDS
Magnitude: 78.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Large field irrigators were tipped over between Grand Rapids and LaMoure.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 02:09:00 to 14-JUL-10 02:14:00 (CST-6)
Location: LA MOURE
Magnitude: 78.00 EG
Property damage: 250.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Widespread tree damage was observed in the city of LaMoure, with most damage consisting of tree branches snapped off of trees. Some areas of the city also had trees uprooted or snapped in half. A pole barn west of LaMoure sustained heavy roof damage along with two large doors blown into the building.

Thunderstorm Wind in HETTINGER, NORTH DAKOTA
From 13-JUL-10 22:14:00 to 13-JUL-10 22:24:00 (MST-7)
Location: REGENT
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Large hail accompanied the strong thunderstorm winds.

Hail in BOWMAN, NORTH DAKOTA
From 13-JUL-10 22:15:00 to 13-JUL-10 22:23:00 (MST-7)
Location: BUFFALO SPGS
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:15:00 to 13-JUL-10 22:25:00 (MST-7)
Location: FREDA
Magnitude: 1.25 
Property damage: 50.00K
Crop damage: 100.00K
Reported by: Trained Spotter

Strong thunderstorm winds combined with the large hail resulting in crop damage and all west side windows on a home broken.

Hail in HETTINGER, NORTH DAKOTA
From 13-JUL-10 22:18:00 to 13-JUL-10 22:27:00 (MST-7)
Location: REGENT
Magnitude: 1.75 
Property damage: 75.00K
Crop damage: 50.00K
Reported by: Emergency Manager

City officials in Regent reported minor hail damage.

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 22:50:00 to 13-JUL-10 23:00:00 (MST-7)
Location: NEW LEIPZIG
Magnitude: 2.75 
Property damage: 1.00M
Crop damage: 500.00K
Reported by: Public

This was the second wave of very large hail to hit New Leipzig during this episode. Homes throughout the city experienced broken windows, damaged siding, and damaged shingles. Vehicles sustained heavy damaged as well.

Hail in HETTINGER, NORTH DAKOTA
From 13-JUL-10 22:54:00 to 13-JUL-10 23:02:00 (MST-7)
Location: MOTT
Magnitude: 1.75 
Property damage: 100.00K
Crop damage: 100.00K
Reported by: Public

Another round of large hail impacted the city of Mott.

Hail in ADAMS, NORTH DAKOTA
From 13-JUL-10 23:00:00 to 13-JUL-10 23:08:00 (MST-7)
Location: BUCYRUS
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GRANT, NORTH DAKOTA
From 13-JUL-10 23:03:00 to 13-JUL-10 23:13:00 (MST-7)
Location: ELGIN
Magnitude: 4.25 
Property damage: 2.00M
Crop damage: 750.00K
Reported by: Public

This was the second wave of very large hail to hit Elgin during this episode. Homes throughout the city experienced broken windows, damaged siding, and damaged shingles. Vehicles sustained heavy damaged as well.

Hail in ADAMS, NORTH DAKOTA
From 13-JUL-10 23:25:00 to 13-JUL-10 23:35:00 (MST-7)
Location: HETTINGER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in GRANT, NORTH DAKOTA
From 14-JUL-10 00:00:00 to 14-JUL-10 00:12:00 (MST-7)
Location: LEITH
Magnitude: 2.00 
Property damage: 0.00K
Crop damage: 350.00K
Reported by: Trained Spotter

The large hail resulted in heavy damage to wheat and sunflower crops.

Hail in MORTON, NORTH DAKOTA
From 14-JUL-10 00:45:00 to 14-JUL-10 00:53:00 (CST-6)
Location: FLASHER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in MORTON, NORTH DAKOTA
From 14-JUL-10 01:15:00 to 14-JUL-10 01:25:00 (CST-6)
Location: HUFF
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 100.00K
Reported by: Trained Spotter

The large hail was accompanied by strong thunderstorm winds.

Hail in EMMONS, NORTH DAKOTA
From 14-JUL-10 01:30:00 to 14-JUL-10 01:43:00 (CST-6)
Location: HAZELTON
Magnitude: 1.75 
Property damage: 20.00K
Crop damage: 50.00K
Reported by: Mesonet

Broken windows resulted from the large hail.

Hail in EMMONS, NORTH DAKOTA
From 14-JUL-10 01:43:00 to 14-JUL-10 01:52:00 (CST-6)
Location: HAZELTON
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in EMMONS, NORTH DAKOTA
From 14-JUL-10 01:44:00 to 14-JUL-10 01:54:00 (CST-6)
Location: HAZELTON
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in STUTSMAN, NORTH DAKOTA
From 14-JUL-10 02:00:00 to 14-JUL-10 02:11:00 (CST-6)
Location: MONTPELIER
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Heavy rain accompanied the strong thunderstorm winds.

Hail in EMMONS, NORTH DAKOTA
From 14-JUL-10 02:05:00 to 14-JUL-10 02:12:00 (CST-6)
Location: KINTYRE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in LOGAN, NORTH DAKOTA
From 14-JUL-10 02:10:00 to 14-JUL-10 02:19:00 (CST-6)
Location: NAPOLEON
Magnitude: 2.75 
Property damage: 45.00K
Crop damage: 200.00K
Reported by: Emergency Manager

Hail in LOGAN, NORTH DAKOTA
From 14-JUL-10 02:12:00 to 14-JUL-10 02:31:00 (CST-6)
Location: BURNSTAD
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 100.00K
Reported by: Mesonet

The large hail resulted in vehicle damage and some crop damage.

Hail in LOGAN, NORTH DAKOTA
From 14-JUL-10 02:15:00 to 14-JUL-10 02:22:00 (CST-6)
Location: GACKLE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in LOGAN, NORTH DAKOTA
From 14-JUL-10 03:00:00 to 14-JUL-10 03:06:00 (CST-6)
Location: BURNSTAD
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Damage was not reported with this severe thunderstorm wind gust.

Hail in HETTINGER, NORTH DAKOTA
From 13-JUL-10 22:22:00 to 13-JUL-10 22:32:00 (MST-7)
Location: BURT
Magnitude: 4.25 
Property damage: 400.00K
Crop damage: 500.00K
Reported by: Emergency Manager

County officials reported up to softball size hail in Burt. All vehicles left outside received major damage. The north side of homes sustained siding damage and broken windows. Roofs were also damaged from the large hail.

Funnel Cloud in GRANT, NORTH DAKOTA
From 13-JUL-10 21:32:00 to 13-JUL-10 21:33:00 (MST-7)
Location: ELGIN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Elgin fire officials who were out spotting saw a funnel cloud just south of Elgin. The funnel did not reach the surface and quickly retreated back into the storm. The funnel cloud was made visible by lightning.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 01:55:00 to 14-JUL-10 02:10:00 (CST-6)
Location: NORTONVILLE
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 50.00K
Reported by: NWS Storm Survey

Corn fields across central LaMoure County were flattened by strong thunderstorm winds. Local residents were unsure if the corn was a partial or complete loss.

Thunderstorm Wind in LA MOURE, NORTH DAKOTA
From 14-JUL-10 02:15:00 to 14-JUL-10 02:21:00 (CST-6)
Location: MARION
Magnitude: 61.00 EG
Property damage: 8.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Strong thunderstorm winds caused a small storage building under construction to collapse.