18Storm-Hp-Ss-Slide-8Tk9-ArticlelargeA fast-moving, deadly storm system Sunday ravaged the Midwest. Officials issued tornado watches throughout the day for wide areas of Illinois, Indiana, Iowa, Michigan, Missouri, Ohio and Wisconsin. By the time the storm had passed on Sunday evening, tornadoes — scores of them, according to the National Weather Service — had left paths of destruction.

Weather officials were uncertain just how many confirmed tornadoes might have hit the region. But as of Sunday evening, the National Weather Service website listed reports of at least 77 — most of them in Illinois — although officials cautioned that in some cases there may have been multiple reports on the same storm.

At least six deaths were reported by early Monday morning. More than 230 flights were canceled at O’Hare International Airport because of the weather, and many other flights were delayed. Flights were also delayed at Midway Airport in Chicago. Wind gusts reached as high as 75 miles per hour in the Chicago area, according to the National Weather Service. The storm caused widespread power failures in Chicago and nearby suburbs.