The official damage report on Wednesday's Dalton area tornado reveals what a powerful and rare tornado it was. A modern, well-built machine shed swept clean off its concrete pad and a nearby home utterly destroyed, its basement full of debris, led the National Weather Service damage survey team to conclude the tornado produced wind speeds of 170 mph, earning an EF4 rating. This is the first EF4 tornado in ten years anywhere in Minnesota and eastern North Dakota.
EF4 and EF5 tornadoes comprise less than 2% of all tornadoes, yet account for a high percentage of the deaths. EF4 tornado winds are between 166 and 200 mph. EF5 tornado winds exceed 200 mph. In recorded history, our region has had only two EF5 tornadoes; Fargo in 1957 and Fergus Falls in 1919.