Thunderstorm Wind in Cook County, Minnesota

There was widespread tree damage near the end of the Gunflint Trail near Seagull Lake. Most damaged trees were blown down.

Southerly winds brought hot and muggy weather conditions to the northern Plains and Upper Midwest, including northeast Minnesota, on Monday (July 21st). A low pressure system was located in north central South Dakota by Monday evening, and its stationary front extended to the northeast through eastern North Dakota and Northwest Wisconsin. Temperatures were in the middle 80s to low 90s in the warm sector, and the combination of dew point temperatures in the upper 60s to middle 70s resulted in heat indices in the 90s to 100s. Thunderstorms developed during the late afternoon and early evening in western North Dakota and formed a mesoscale convective complex. This MCV then became a derecho Monday evening as it moved and bowed east through eastern North Dakota and the northern Minnesota and northern Wisconsin late Monday and early Tuesday (July 22nd). This derecho caused widespread wind damage from winds of at least 50 to 70 mph over much of northeast Minnesota, blowing and/or snapping trees and knocking out power. There were more focused areas of structural damage that suggested there were winds in excess of 70 mph. There were several injuries to campers in the Boundary Waters Canoe Area Wilderness due to falling trees, which required officials to make some rescues.