$11 billion in losses from the Aug. 10, 2020 Midwest derecho made it the most expensive thunderstorm event in modern U.S. history, according to NOAA and the National Weather Service.
100 mph winds drove the storm for hours from Nebraska across Iowa into Wisconsin, Illinois, Indiana and Michigan—far above the 58 mph threshold used to classify a derecho.
11 tornadoes were confirmed in Illinois from the same storm system, including an EF-1 in Chicago's Rogers Park and others in Yorkville, Plainfield, Rockford and Ottawa.
The scale dwarfed a 2009 super derecho that traveled more than 1,000 miles in 24 hours and caused about $500 million in damage, underscoring how exceptional the 2020 event was.