Conditions were ripe by the afternoon of the 17th for a major severe weather outbreak. A surface low had moved into east central North Dakota with an occluded front extending to the southeast. Warm and humid air was in place ahead of the front, with a much drier airmass pushing in behind it. The 500mb low was located over northwest North Dakota with a nice southwest to northeast upper jet pushing into eastern North Dakota. Two lines of convection formed by late afternoon, one from Roseau County down toward Eastern Otter Tail County and the other over east central North Dakota. Nearly all the cells that formed took on a classic hook shape with rotation very evident on radar imagery. Multiple tornado warnings were issued before the event wound down by mid evening. The strongest tornadoes were determined to be EF4 tornadoes, two in west central Minnesota and one in northeast North Dakota.

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:35:00 to 17-JUN-10 16:42:00 (CST-6)
Location: ORR
Tornado F-scale: EF1
Reported by: NWS Storm Survey

The tornado tracked northward for about 4 miles. Several large trees were snapped or uprooted in shelterbelts. Peak winds were estimated at 95 mph.

Tornado in STEELE, NORTH DAKOTA
From 17-JUN-10 14:38:00 to 17-JUN-10 14:45:00 (CST-6)
Location: FINLEY
Tornado F-scale: EF0
Reported by: NWS Employee

The tornado report was relayed by an off duty Dodge City NWS meteorologist chasing the storm. The tornado tracked northward intermittently for about 4 miles. Damage was not noticed as the tornado remained largely over open fields and rangeland. Peak winds were estimated at 80 mph.

Tornado in STEELE, NORTH DAKOTA
From 17-JUN-10 15:28:00 to 17-JUN-10 15:38:00 (CST-6)
Location: HOPE
Tornado F-scale: EF2
Reported by: Law Enforcement

The tornado tracked northward for nearly 7 miles, to around 1 mile north of Blabon. The tornado produced severe tree damage in field and farm shelterbelts located along its path. Rear flank downdraft winds also produced tree damage at the Hope golf course. Peak winds were estimated at 120 mph.

Hail in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:39:00 to 17-JUN-10 16:39:00 (CST-6)
Location: (GFK)GRAND FORKS INT
Magnitude: 1.25 
Reported by: ASOS

The hail was reported in the 2239Z observation at the Grand Forks International Airport.

Tornado in WALSH, NORTH DAKOTA
From 17-JUN-10 16:41:00 to 17-JUN-10 16:45:00 (CST-6)
Location: FORDVILLE ARPT
Tornado F-scale: EF1
Reported by: Fire Department/Rescue

The tornado tracked northward for about 2 miles. Trees were snapped or uprooted in shelterbelts. Peak winds were estimated at 95 mph.

Tornado in STEELE, NORTH DAKOTA
From 17-JUN-10 15:30:00 to 17-JUN-10 15:39:00 (CST-6)
Location: COLGATE
Tornado F-scale: EF1
Reported by: NWS Storm Survey

The tornado tracked northward intermittently for nearly 7 miles. Trees were damaged in shelterbelts and farm yards. A center pivot irrigation system was tumbled and twisted near Colgate. Peak winds were estimated at 95 mph.

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 15:05:00 to 17-JUN-10 15:18:00 (CST-6)
Location: HOLMES
Tornado F-scale: EF4
Reported by: NWS Storm Survey

This tornado began in Traill County about 3 miles north-northeast of Mayville at 349 PM CDT. The tornado crossed into Grand Forks County and tracked for an additional 8 miles to about 10 miles west of Thompson. The total track length was roughly 17 miles. One well constructed house near Holmes was completely swept from its foundation and destroyed along with several other farm buildings. Peak winds were estimated at 185 mph.

Tornado in BARNES, NORTH DAKOTA
From 17-JUN-10 15:01:00 to 17-JUN-10 15:03:00 (CST-6)
Location: BEREA
Tornado F-scale: EF1
Reported by: Public

The tornado tracked northward for about a mile to about 1 mile west-southwest of the Baldhill Dam. The tornado snapped a wooden power pole, knocked down several poplar trees, and shredded a portion of an old corn field. Peak winds were estimated at 100 mph.

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 15:31:00 to 17-JUN-10 15:42:00 (CST-6)
Location: OJATA
Tornado F-scale: EF2
Reported by: Law Enforcement

The tornado tracked northward intermittently for about 7 miles. A pole barn and several farm outbuildings were destroyed. Large trees were snapped or uprooted. Debris was thrown near Emerado and just east of the Grand Forks Air Force Base. Peak winds were estimated at 120 mph.

Tornado in STEELE, NORTH DAKOTA
From 17-JUN-10 15:40:00 to 17-JUN-10 15:45:00 (CST-6)
Location: HOPE
Tornado F-scale: EF2
Reported by: NWS Storm Survey

The tornado tracked northeastward for nearly 3 miles to around 8 miles east-northeast of Hope. Numerous trees were severely damaged in shelterbelts. An abandoned farmhouse was collapsed and other farm buildings were damaged. Peak winds were estimated at 125 mph.

Hail in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:43:00 to 17-JUN-10 16:43:00 (CST-6)
Location: GRAND FORKS
Magnitude: 1.25 
Reported by: Amateur Radio

Tornado in BARNES, NORTH DAKOTA
From 17-JUN-10 15:05:00 to 17-JUN-10 15:05:00 (CST-6)
Location: DAZEY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Multiple funnel clouds were viewed to the west, southwest, and south of Dazey, all moving northward. One produced a brief touchdown in an open field near Dazey, though no damage was observed. Peak winds were estimated at 80 mph.

Funnel Cloud in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 15:46:00 to 17-JUN-10 15:46:00 (CST-6)
Location: (GFK)GRAND FORKS INT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Observers at the Grand Forks International Airport reported a wall cloud south of the airport complex moving north. Subsequent reports indicated a tornado passing near the airport from 2147Z to 2151Z. Peak winds at the airport reached 48 knots as the tornado passed west of the airport.

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 15:47:00 to 17-JUN-10 16:04:00 (CST-6)
Location: (GFK)GRAND FORKS INT
Tornado F-scale: EF1
Reported by: Amateur Radio

The tornado touched down just west of the Grand Forks International Airport and tracked northward for nearly 10 miles. The tornado did lift briefly around 501 PM CDT before reforming with two tornadic vortices extending from a common wall cloud. The twin tornadoes then tracked cyclically up to a mile apart while they snapped and uprooted trees in shelterbelts and collapsed a pole barn. Peak winds were estimated at 100 mph.

Tornado in TRAILL, NORTH DAKOTA
From 17-JUN-10 14:49:00 to 17-JUN-10 15:05:00 (CST-6)
Location: PORTLAND JCT
Tornado F-scale: EF4
Reported by: NWS Storm Survey

The tornado tracked northward for nearly 9 miles to about 12 miles north of Mayville by 405 PM CDT and crossed into Grand Forks County. It then continued for another 8 miles to around 10 miles west of Thompson by 418 PM CDT, for a total track length of nearly 17 miles. Trees in shelterbelts and farmsteads were snapped, uprooted, or sheared off. One well constructed house near Holmes was completely swept from its foundation and destroyed. Peak winds were estimated at 185 mph. A farm shop about five and one-half miles north of Mayville was hit by the tornado, destroying the shop. A man inside survived with cuts on his hand.

Tornado in WALSH, NORTH DAKOTA
From 17-JUN-10 16:21:00 to 17-JUN-10 16:23:00 (CST-6)
Location: POLAND
Tornado F-scale: EF1
Reported by: Law Enforcement

A funnel cloud was observed forming to the north of the Interstate 29 exit west of Oslo, Minnesota, at 518 PM CDT. The tornado tracked for nearly a mile before crossing the Red River and continuing into Minnesota about 5 miles north of Oslo, Marshall County. The tornado continued for another 4 miles in Minnesota, ending by 529 PM CDT. Several large trees were snapped near the river. Peak winds were estimated at 90 mph.

Tornado in STEELE, NORTH DAKOTA
From 17-JUN-10 16:02:00 to 17-JUN-10 16:05:00 (CST-6)
Location: SHERBROOKE
Tornado F-scale: EF0
Reported by: NWS Storm Survey

The tornado tracked for about 2 miles to near 5 miles south-southeast of Northwood. The tornado was viewed by spotters near Golden Lake and the town of Hatton. Several tree tops were snapped along the Goose River. Peak winds were estimated at 80 mph.

Thunderstorm Wind in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 15:15:00 to 17-JUN-10 15:15:00 (CST-6)
Location: HOLMES
Magnitude: 78.00 EG
Reported by: COOP Observer

Numerous large trees were blown down or snapped in farmsteads by thunderstorm forward flank downdraft winds.

Hail in RAMSEY, NORTH DAKOTA
From 17-JUN-10 15:20:00 to 17-JUN-10 15:20:00 (CST-6)
Location: FT TOTTEN STATION
Magnitude: 1.00 
Reported by: COOP Observer

Thunderstorm Wind in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 15:25:00 to 17-JUN-10 15:25:00 (CST-6)
Location: EMERADO
Magnitude: 60.00 EG
Reported by: NWS Storm Survey

Numerous trees were blown down in shelterbelts.

Tornado in NELSON, NORTH DAKOTA
From 17-JUN-10 16:15:00 to 17-JUN-10 16:19:00 (CST-6)
Location: DAHLEN
Tornado F-scale: EF0
Reported by: NWS Storm Survey

The tornado tracked northeastward intermittently for about 3 miles. Several large branches and tree limbs were knocked down in shelterbelts. Peak winds were estimated at 80 mph.

Tornado in EDDY, NORTH DAKOTA
From 17-JUN-10 15:27:00 to 17-JUN-10 15:28:00 (CST-6)
Location: SHEYENNE
Tornado F-scale: EF0
Reported by: Law Enforcement

The tornado tracked northward over open rangeland for about a mile and then it crossed into Benson County about 8 miles west of Warwick at 428 PM CDT. Peak winds were estimated at 70 mph.

Funnel Cloud in TRAILL, NORTH DAKOTA
From 17-JUN-10 16:15:00 to 17-JUN-10 16:15:00 (CST-6)
Location: REYNOLDS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:22:00 to 17-JUN-10 16:24:00 (CST-6)
Location: ORR
Tornado F-scale: EF0
Reported by: NWS Storm Survey

The tornado tracked northward over open fields for about a mile. Some large tree limbs were broken down in a shelterbelt. Peak winds were estimated at 75 mph.

Tornado in BENSON, NORTH DAKOTA
From 17-JUN-10 15:28:00 to 17-JUN-10 15:28:00 (CST-6)
Location: TOKIO
Tornado F-scale: EF0
Reported by: Law Enforcement

The tornado began in Eddy County about 11 miles east of Sheyenne at 427 PM CDT. The tornado crossed into Benson County and dissipated over open pastureland. Peak winds were estimated at 70 mph.

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:30:00 to 17-JUN-10 16:43:00 (CST-6)
Location: THOMPSON
Tornado F-scale: EF0
Reported by: NWS Employee

The tornado produced intermittent touchdowns along a nearly 8 mile north-northeast track. The dissipating funnel was visible passing south of Grand Forks through 545 PM CDT. Large tree branches were broken down in field shelterbelts and near homes in Merrifield. Peak winds were estimated at 80 mph.

Thunderstorm Wind in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:31:00 to 17-JUN-10 16:31:00 (CST-6)
Location: (GFK)GRAND FORKS INT
Magnitude: 50.00 MG
Reported by: ASOS

The wind gust was measured by the Grand Forks International Airport ASOS.

Tornado in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:37:00 to 17-JUN-10 16:40:00 (CST-6)
Location: GILBY
Tornado F-scale: EF0
Reported by: Trained Spotter

The tornado tracked northward intermittently for about two miles. No damage was detected as the tornado stayed largely over open fields. Peak winds were estimated at 75 mph.

Hail in GRAND FORKS, NORTH DAKOTA
From 17-JUN-10 16:34:00 to 17-JUN-10 16:34:00 (CST-6)
Location: GRAND FORKS
Magnitude: 1.00 
Reported by: Trained Spotter

Funnel Cloud in STEELE, NORTH DAKOTA
From 17-JUN-10 14:24:00 to 17-JUN-10 14:24:00 (CST-6)
Location: PICKERT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

The report was relayed by an off duty Dodge City NWS meteorologist chasing the storm. The developing funnel cloud tracked nearly due north before the initial tornado touchdown about 5 miles north-northeast of Finley around 338 PM CDT.