EF3 tornado in Polk County, Minnesota

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.

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.