Late Tuesday Afternoon Update:
Tens of thousands of people in northern Illinois were without electricity hours after a fast-moving thunderstorm downed trees and severed power lines.
The early morning storm knocked out power to about 300,000 homes and businesses in the northern part of the state.
Commonwealth Edison said that by mid-afternoon, 91,000 customers were still without electricity, most of them to the west of Chicago.
Company officials expect power will be restored to most of them by Thursday evening or Friday.