Monday’s storm, which spawned at least 7 tornados, one of the worst in a decade

Monday’s derecho was one of the most powerful and devastating storms to hit Northern Illinois in a decade, a top official with ComEd said Wednesday.

“This storm was incredibly fierce and incredibly fast,” said Rich Negrin, ComEd’s vice president for external affairs. “It hit so many of our customers — all very, very quickly in a very short period of time.”

Of the roughly 850,000 customers — mostly residential — who lost power during the storm, about 80 percent had their electricity back on by late Wednesday morning. The “overwhelming majority” of the remainder should have power restored within the next 48 hours, Negrin said.

The National Weather Service confirmed seven tornados touched down in Illinois on Monday: Two in Rockford and one each in the Rogers Park neighborhood, Lombard, Spring Grove, Marengo and Wheaton.

The last time a tornado touched down in Chicago was Sept. 3, 2018, according to the weather service, but that was a category F-0 twister, the least powerful on the Fujita Tornado damage scale. An F-1 tornado, the kind that churned through Rogers Park on Monday, last struck the city on May 29, 1983, near Hawthorne Race Course, according to the weather service.

Negrin said the storms were so bad Monday that several of ComEd’s transmission towers were knocked down.

“That’s not just a repair, that’s a rebuild. You’re talking about bringing in new equipment,” he said.

Besides the city, where more than 100,000 customers lost power, some of the worst-hit areas were farther south — in Harvey and Joliet, Negrin said.

“We rarely have ever had a storm that hits our entire service territory ... all at the same time,” he said.