Irene has come and gone, but the power companies might take a week or more to get the lights back on for thousands of households and businesses left in the dark from the powerful storm.

At one point, 672,000 Connecticut Light & Power customers were without power Sunday. As of 3 p.m. on Monday morning, power was back on for thousands of people, but electricity remains out for more than 560,000 as of 4:20 p.m.

United Illuminating had more than 157,000 customers in the dark as well. That number was down. As of 4:15 p.m., on Monday, power is out for 102,789. The site is not working, so UI is providing e-mail updates.

"We could be rebuilding whole sections of the electrical infrastructure," CL&P spokesperson Mitch Gross said as the storm was moving through.

CL&P deployed 800 crews on Sunday afternoon to begin the restoration process, but could not put a timetable on how long it would take to turn the lights back on.

Those who have suffered power outages in the past and waited a long time to have the electricity turned back on should expect to wait a long time again, Gov. Dannel Malloy said on Sunday night.

Both CL&P and UI warned people to stay away from downed wires and to assume that those wires are live.