61,000 lose power after storm hits Chicago

More than 61,000 ComEd customers lost power during Monday evening storms that swept through Chicago, and over 1,000 remained without power into Tuesday afternoon.

The storm's gusts of 70 mph caused tree limbs to fall on power lines. Power outages hit Elgin and Rockford the hardest, said ComEd spokesperson Tom Dominguez.

"The main cause of the outages were the storms packing high winds, which brought a lot of tree limbs down onto power lines," Dominguez said.

Power had been restored to 98% of customers Tuesday morning, according to ComEd. About 283 customers were still without power at 3:30 p.m., the largest concentrations being around Wheaton and Carpentersville; the company said all power would be restored by 6 p.m.

The high winds were caused by a wake low, occurring when warm air sinks and causes a drop in pressure on the edge of a decaying line of thunderstorms or rain. The difference in pressure with the cold air then creates the damaging winds, according to the National Weather Service.

"That caused instances of tree damage and even some minor structural damage," said Ricky Castro, a meteorologist with the weather service.

Nearly nine-tenths of an inch of rain fell at O'Hare Monday, while over an inch fell at Midway, the weather service said. The totals were less than the storms could have brought to the area. Instead, central Illinois got hit hardest.

"The fact that we missed out on the worst of the rain did kind of help in terms of not really exacerbating the flooding situation that had been ongoing," Castro said. "That could have been a bigger issue in terms of flooding, developing renewed rises on rivers [and] places that have been hard hit by river flooding of late."

Tuesday's temperatures reached into the mid-60s ahead of some lighter showers that were set return to the Chicago area Tuesday night into early Wednesday. High temperatures are forecast to remain in the 50s through the rest of the week.