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 PENNINGTON, MINNESOTA
From 17-JUN-10 16:10:00 to 17-JUN-10 16:13:00 (CST-6)
Location: GOODRIDGE
Tornado F-scale: EF1
Reported by: Public

The tornado tracked northward intermittently for roughly 2 miles. The tornado knocked down several large tree limbs and snapped off some smaller trees. Heavy farm machinery was moved around by the winds. Peak winds were estimated at 90 mph.

Tornado in WADENA, MINNESOTA
From 17-JUN-10 16:30:00 to 17-JUN-10 16:37:00 (CST-6)
Location: NIMROD
Tornado F-scale: EF0
Reported by: NWS Storm Survey

The tornado tracked east-northeastward intermittently for about 5 miles, where it reached the Cass County line east of Nimrod. The tornado continued northeast into Cass County for several more miles. Numerous large tree branches were broken down along this path. Peak winds were estimated at 80 mph.

Tornado in HUBBARD, MINNESOTA
From 17-JUN-10 16:49:00 to 17-JUN-10 16:51:00 (CST-6)
Location: BENEDICT
Tornado F-scale: EF0
Reported by: NWS Storm Survey

The tornado tracked northeastward for about a mile against the west end of Lake Kabekona. Several large branches were broken down along its path. Peak winds were estimated at 80 mph.

Tornado in OTTER TAIL, MINNESOTA
From 17-JUN-10 14:55:00 to 17-JUN-10 14:56:00 (CST-6)
Location: VERGAS
Tornado F-scale: EF0
Reported by: Storm Chaser

Two persistent wall clouds tracked with periodic funnels from north central Otter Tail County into south central Becker County. One produced a brief tornadic touchdown near Rose Lake in Hobart Township. Peak winds were estimated at 75 mph.

Thunderstorm Wind in RED LAKE, MINNESOTA
From 17-JUN-10 17:20:00 to 17-JUN-10 17:20:00 (CST-6)
Location: RED LAKE FALLS
Magnitude: 70.00 EG
Reported by: Newspaper

Numerous large tree branches were broken down and several trees were uprooted by violent wind bursts. The winds were accompanied by a steady downpour of rain.

Tornado in MARSHALL, MINNESOTA
From 17-JUN-10 17:26:00 to 17-JUN-10 17:36:00 (CST-6)
Location: RADIUM
Tornado F-scale: EF1
Reported by: Trained Spotter

This tornado tracked for roughly 7 miles, snapping off numerous trees in shelterbelts along its path. The roof was torn off a small shed near Old Mill State Park and some row crops showed ground scouring. Peak winds were estimated at 105 mph.

Tornado in MARSHALL, MINNESOTA
From 17-JUN-10 16:23:00 to 17-JUN-10 16:29:00 (CST-6)
Location: BIG WOODS
Tornado F-scale: EF1
Reported by: Emergency Manager

This tornado began in Walsh County, North Dakota, about 4 miles north-northwest of Oslo, Minnesota, at 521 PM CDT. It crossed the Red River into Minnesota about 5 miles north of Oslo. The tornado continued to track northeastward for about 4 miles. Numerous large tree limbs were knocked down and several trees were snapped in shelterbelts. Peak winds were estimated at 90 mph.

Tornado in CLEARWATER, MINNESOTA
From 17-JUN-10 16:29:00 to 17-JUN-10 16:31:00 (CST-6)
Location: CLEARBROOK
Tornado F-scale: EF1
Reported by: Newspaper

The tornado tracked northward for roughly a mile. Several large trees were knocked down onto power lines and one power pole was snapped along highway 92. Peak winds were estimated at 100 mph.

Hail in POLK, MINNESOTA
From 17-JUN-10 16:45:00 to 17-JUN-10 16:45:00 (CST-6)
Location: EAST GRAND FORKS
Magnitude: 1.00 
Reported by: Trained Spotter

Tornado in HUBBARD, MINNESOTA
From 17-JUN-10 16:48:00 to 17-JUN-10 16:54:00 (CST-6)
Location: KABEKONA CORNER
Tornado F-scale: EF0
Reported by: NWS Storm Survey

This tornado tracked northeastward intermittently for roughly 4 miles. The tornado knocked down several large tree branches along its route. Peak winds were estimated at 80 mph.

Tornado in OTTER TAIL, MINNESOTA
From 17-JUN-10 15:48:00 to 17-JUN-10 15:50:00 (CST-6)
Location: BLUFFTON
Tornado F-scale: EF1
Reported by: Trained Spotter

This tornado tracked briefly to the north-northeast before a wet rear-flank downdraft overtook it as viewed and recorded by multiple storm chase teams. A second and more powerful tornado eventually formed from the parent supercell thunderstorm and impacted the the community of Wadena.  Very heavy rains and damaging downdraft winds obscured the overall tornado path.  However large tree limbs were broken down and smaller trees were uprooted by the event suggesting peak winds to 90 mph.

Thunderstorm Wind in OTTER TAIL, MINNESOTA
From 17-JUN-10 15:10:00 to 17-JUN-10 15:12:00 (CST-6)
Location: PARKERS PRAIRIE
Magnitude: 126.00 MG
Property damage: 300.00K
Crop damage: 0.00K
Reported by: Mesonet

Peak 3 second wind gusts of from 128 to 145 mph were measured by 6 different wind sensors placed at heights of from 160 to 380 feet AGL at a temporary wind energy monitoring tower site.  Peak 3 second wind gusts of 119 mph were measured at a height of 20 feet AGL at this same tower site.  These measurements were made as a tornado struck the site, and just prior to the collapse of the tower.

Tornado in POLK, MINNESOTA
From 17-JUN-10 16:50:00 to 17-JUN-10 17:00:00 (CST-6)
Location: FREEMAN
Tornado F-scale: EF1
Reported by: NWS Employee

A well defined tornado was viewed by an off duty SPC meteorologist. The tornado tracked northward intermittently for roughly 7 miles. The tornado snapped or uprooted numerous trees in shelterbelts and damaged farm buildings near the Fisher/Nesbit township border. Peak winds were estimated at 100 mph.

Tornado in NORMAN, MINNESOTA
From 17-JUN-10 14:28:00 to 17-JUN-10 14:30:00 (CST-6)
Location: FOSSUM
Tornado F-scale: EF0
Reported by: Emergency Manager

The tornado tracked northeast for about 1 mile. Several tree limbs were snapped off in a country cemetery south of Fossum. Peak winds were estimated at 80 mph.

Hail in MAHNOMEN, MINNESOTA
From 17-JUN-10 14:59:00 to 17-JUN-10 14:59:00 (CST-6)
Location: BEJOU
Magnitude: 2.00 
Reported by: Newspaper

Golf ball to hen egg sized hail fell.

Tornado in MAHNOMEN, MINNESOTA
From 17-JUN-10 15:00:00 to 17-JUN-10 15:07:00 (CST-6)
Location: BEJOU
Tornado F-scale: EF0
Reported by: NWS Storm Survey

The tornado tracked northeastward for roughly 4 miles, where it then crossed into Polk County at 407 PM CDT. The tornado continued in Polk County for another 2 miles. Several trees were knocked down in farm shelterbelts. The total track length was about 6 miles with peak winds estimated at 80 mph.

Funnel Cloud in POLK, MINNESOTA
From 17-JUN-10 15:08:00 to 17-JUN-10 15:08:00 (CST-6)
Location: FOSSTON MUNI ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Funnels were viewed both northwest and southwest of Fosston, moving to the north-northeast.

Tornado in POLK, MINNESOTA
From 17-JUN-10 15:07:00 to 17-JUN-10 15:10:00 (CST-6)
Location: WINGER
Tornado F-scale: EF0
Reported by: NWS Storm Survey

This tornado began in Mahnomen County about 3 miles east of Bejou at 400 PM CDT. It crossed into Polk County and tracked for another 2 miles, giving a total track length of about 6 miles. The tornado knocked down several trees in farm shelterbelts. Peak winds were estimated at 80 mph.

Tornado in POLK, MINNESOTA
From 17-JUN-10 17:00:00 to 17-JUN-10 17:04:00 (CST-6)
Location: GENTILLY
Tornado F-scale: EF1
Reported by: NWS Storm Survey

This tornado tracked northeastward for nearly 3 miles. The tornado tore a 5,000 bushel steel grain bin from its concrete pad and tossed it a half mile into a field. Several trees were snapped off or uprooted in a shelterbelt and shingles were torn from a house roof. Peak winds were estimated at 90 mph.

Tornado in POLK, MINNESOTA
From 17-JUN-10 17:06:00 to 17-JUN-10 17:10:00 (CST-6)
Location: ANGUS
Tornado F-scale: EF0
Reported by: Trained Spotter

This tornado tracked northward for roughly 2 miles. Several large tree limbs were knocked down in shelterbelts along the tornado path. One farmstead received minor shingle damage. Peak winds were estimated at 85 mph.

Tornado in OTTER TAIL, MINNESOTA
From 17-JUN-10 14:45:00 to 17-JUN-10 15:45:00 (CST-6)
Location: URBANK
Tornado F-scale: EF4
Reported by: NWS Storm Survey

This tornado began in Douglas County, Minnesota. It moved northward into Otter Tail County and produced an additional 38 miles of continuous damage path. The tornado destroyed numerous homes and farmsteads along its path, completely sweeping 7 homes from their foundations. At times, this multi-vortex tornado complex consisted of multiple tornadic tubes pivoting around a common center. Peak winds were estimated at 175 mph.

Tornado in POLK, MINNESOTA
From 17-JUN-10 17:15:00 to 17-JUN-10 17:27:00 (CST-6)
Location: MAPLE BAY
Tornado F-scale: EF3
Reported by: Emergency Manager

This tornado began in Polk County and tracked northeastward for nine miles to the Red Lake County line about 5 miles north-northeast of Mentor. After crossing into Red Lake County, it continued for an additional 6 miles. The tornado tracked across Maple Lake and the community of Mentor. Trees were sheared off or uprooted, power poles were snapped, and roofs and garages were destroyed. A convenience store and gas station along U. S. Highway 2 were flattened. Cabins, campers, boats, and docks were damaged along the northeast side of Maple Lake. Peak winds were estimated at 145 mph.

Tornado in ROSEAU, MINNESOTA
From 17-JUN-10 16:49:00 to 17-JUN-10 16:51:00 (CST-6)
Location: SKIME
Tornado F-scale: EF1
Reported by: Trained Spotter

This tornado began in Marshall County about 11 miles north of Grygla at 554 PM CDT. The tornado continued into Roseau County and tracked northeastward for roughly a mile. Several large trees were knocked down or snapped along the tornado path. Peak winds were estimated at 95 mph.

Tornado in MARSHALL, MINNESOTA
From 17-JUN-10 16:44:00 to 17-JUN-10 16:49:00 (CST-6)
Location: GATZKE
Tornado F-scale: EF1
Reported by: Trained Spotter

The tornado tracked northward for roughly 3 miles along the Marshall and Beltrami county line, before crossing into Roseau County just south of Skime. The tornado continued northeastward into Roseau County for about one mile and lifted about 1 mile east of Skime. Several large trees were knocked down or snapped along the tornado path. Peak winds were estimated at 95 mph.

Tornado in WADENA, MINNESOTA
From 17-JUN-10 16:02:00 to 17-JUN-10 16:16:00 (CST-6)
Location: WADENA
Tornado F-scale: EF4
Reported by: Storm Chaser

This multi-vortex wedge tornado began in Otter Tail County about 3 miles southwest of the city of Wadena at 459 PM CDT. It tracked for about 2 miles in Otter Tail County, then it continued for another 8 miles in Wadena County. The tornado ravaged the western half of the community of Wadena. Numerous homes were flattened to the ground and at least one was completely swept from its foundation and destroyed. Public and industrial buildings were wrecked, the fairgrounds were damaged, and headstones in the cemetery were overturned. School buses and vehicles were propelled through the air for hundreds of yards. The tornado hit on the day of the Wadena all-school reunion, so many additional people were in the area. Roughly 100 people were displaced from their homes. Peak winds were estimated at 170 mph.

Funnel Cloud in POLK, MINNESOTA
From 17-JUN-10 15:22:00 to 17-JUN-10 15:22:00 (CST-6)
Location: FOSSTON MUNI ARPT
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornado in CLEARWATER, MINNESOTA
From 17-JUN-10 15:32:00 to 17-JUN-10 15:34:00 (CST-6)
Location: LAKE ITASCA
Tornado F-scale: EF1
Reported by: Newspaper

This tornado tracked north-northeastward for roughly a mile, across portions of Long Lost Lake. Numerous large tree limbs were knocked down and large trees were snapped. Peak winds were estimated at 90 mph.

Tornado in CLEARWATER, MINNESOTA
From 17-JUN-10 15:41:00 to 17-JUN-10 15:46:00 (CST-6)
Location: ZERKEL
Tornado F-scale: EF1
Reported by: NWS Storm Survey

This tornado tracked nearly due north for about 3 miles. The tornado knocked down numerous large tree limbs and uprooted or snapped off several trees. Some shingles, gutters, and trim pieces were torn off of a house. Peak winds were estimated at 95 mph.

Tornado in RED LAKE, MINNESOTA
From 17-JUN-10 17:27:00 to 17-JUN-10 17:36:00 (CST-6)
Location: TERREBONNE
Tornado F-scale: EF3
Reported by: Emergency Manager

This tornado began in Polk County, about 4 miles south-southwest of Mentor at 615 PM CDT. The tornado tracked into Red Lake County and continued an additional 6 miles to roughly 4 miles east-northeast of Terrebonne. The tornado sheared trees and blew down farm buildings near the Polk County line and lofted debris from Mentor well past the community of Plummer. The total track length was about 15 miles and peak winds were estimated at 145 mph.

Tornado in RED LAKE, MINNESOTA
From 17-JUN-10 17:16:00 to 17-JUN-10 17:19:00 (CST-6)
Location: DOROTHY
Tornado F-scale: EF1
Reported by: Emergency Manager

This tornado tracked northeastward for roughly 2 miles. The tornado blew a parked semi tractor-trailer rig off the highway and injured the driver. Peak winds were estimated at 90 mph.

Tornado in OTTER TAIL, MINNESOTA
From 17-JUN-10 15:59:00 to 17-JUN-10 16:02:00 (CST-6)
Location: BLUFFTON
Tornado F-scale: EF4
Reported by: Trained Spotter

This tornado touched down in Otter Tail County and tracked northeastward for about 2 miles before crossing into Wadena County just southwest of the Wadena city limits. The tornado developed rapidly into a multi-vortex wedge type tornado as it approached Wadena. The tornado continued in Wadena County another 8 miles and ended about 516 PM CDT. Otter Tail County received mainly extreme tree damage with peak winds estimated at 170 mph.

Tornado in HUBBARD, MINNESOTA
From 17-JUN-10 16:17:00 to 17-JUN-10 16:26:00 (CST-6)
Location: LAKE GEORGE
Tornado F-scale: EF1
Reported by: Trained Spotter

The tornado tracked northeast for roughly 6 miles. The tornado knocked down numerous large tree limbs and snapped or uprooted several large trees from the southeast edge of Itasca State Park, across portions of Beauty Lake, and Lake Alice. Peak winds were estimated at 100 mph.