Chicago, IL – A historic storm on July 15 brought 32 tornadoes to Illinois and Indiana, marking the most significant severe weather event recorded in the region. The National Weather Service (NWS) confirmed the tornado count after extensive post-survey work.
According to the NWS Chicago, the derecho was responsible for at least 50 tornadoes across Iowa, Wisconsin, Illinois, and Indiana, with 32 occurring in the NWS Chicago forecast area. This makes it the most prolific tornado event since reliable records began in 1950.
The derecho, which swept through with intense winds and multiple tornadoes, caused widespread damage. Areas like Winnebago, Ogle, DeKalb Counties experienced straight-line winds up to 90 mph. The storm system also hit northern Illinois and northwestern Indiana, where five counties faced severe impacts.
In total, over 1,500 individual reports of damage were analyzed. Emergency management partners, trained spotters, and high-resolution satellite data contributed to the comprehensive survey.
The official report on this event will be finalized in November.
