EF1 tornado in Walsh County, North Dakota

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.

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.