Utilities scrambled Monday to restore power to more than 4 million customers still left in the dark by Hurricane Irene.
Power companies already have the lights back on for almost half the 8 million homes and businesses that lost electricity over the weekend. But in areas of severe damage, it could take weeks for power to be fully restored.
Repair crews have struggled to get around uprooted trees, broken bridges and flooding left by Irene.
The storm smashed power poles, ripped transmission wires and flooded electrical stations over thousands of square miles as it whipped north from South Carolina to Maine. Most of damage came from downed trees. At least 38 people in 11 states died in the storm.
Northern cities were still surveying the damage. The storm ranks among the worst in terms of power outages. Vermont experienced the worst flooding in generations. Parts of New Jersey were cut off by swollen rivers. Half of Connecticut Light & Power customers were in the dark.
"This is just unprecedented," the Connecticut utility's spokesman, David Radanovich, said. "The largest storm we've ever faced."
As 750,000 of the utility's customers lost power over the weekend, Connecticut Light & Power requested outside help. About 200 to 300 additional crews are headed to the state.
Utilities say they'll first repair damaged lines that power hospitals, jails, emergency call centers and other critical services. They'll try to get the lights on in public schools before the fall semester begins. Other repairs will need to wait.
Elaine Shecker found a tree across her driveway when she returned to her house in Media, Pa., just outside of Philadelphia. The power company said it might be three more days before the electricity gets restored. Shecker wasn't complaining.
"We feel lucky to have a house," she said. "This storm killed people."
Public Service Electric and Gas Company, New Jersey's largest utility, said several thousand homes lost power when electrical substations were flooded. Those stations will remain offline until crews can pump out the water and dry the equipment.
"That takes days," PSE&G spokeswoman Karen Johnson said. "The flooding is kind of overwhelming."
In Vermont, hundreds of people were ordered to evacuate as streams and rivers rose above their banks. Gov. Peter Shumlin called it the worst flooding in a century.
More than 37,000 Vermonters were without power Monday, and officials said it could take weeks for power to come back.
"In many places, we can't even get to the damage," said Joe Kraus, operations chief at Central Vermont Public Service.
Across the East Coast, power companies said most of the damage came from trees that smashed into transmission lines and other electrical equipment.
"Just lots of trees down," said Linda Foy, a spokeswoman with Baltimore Gas & Electric. "We've got whole trees knocked into equipment; large limbs the size of small trees hanging on power lines."
Repair crews focused on the most damaged parts of the grid. They started with the transmission lines and substations that feed the largest parts of the grid before spreading out to individual neighborhoods.
Much of the damage is expected to be repaired within a few days, while some hard-to-reach areas could be cut off for days or weeks.
PECO, which serves southern Pennsylvania, said that 90 percent of its power outages will be fixed by Wednesday.
In Washington D.C., Pepco Holdings Inc. said it will complete most repairs by Thursday. Baltimore Gas & Electric, Long Island Power Authority in New York and Dominion Resources in Virginia said most of their outages should restored by Friday.
Other power companies weren't so sure. Some said it may take a few days, while others were hunkering down for many more nights in the dark.
"In some places we still need to wait for the flood waters to recede," said Ron Morano with Jersey Central Power & Light in New Jersey. "I'm not sure how long that takes."
Chris Kahn can be reached at http://twitter.com/ChrisKahnAP
Randy Pennell in Media, Pa. contributed to this story.