A man inspects an ice covered downed tree that took out a utility line and landed atop a minivan on Wednesday after a winter storm in Philadelphia. Hundreds of thousands are without electricity.

HARRISBURG — Utility crews aren't getting much relief from the weather as they work to restore electricity to hundreds of thousands of people in Pennsylvania and Maryland, two days after an ice storm downed power lines and trees.

Forecasters said the cold weather gripping the mid-Atlantic today should remain in place through the weekend, and snow was possible.

Utility companies reported more than 325,000 customers without power in Pennsylvania, along with about 50,000 in Maryland. Officials have said they hope to have most of them back online by the end of today, but in some cases it might take much of the weekend.

PECO, the dominant electricity provider in the Philadelphia area, reports more than 288,000 customers out this morning in the five-county area. First Energy has about 27,550, almost all west of the city in York County, where there are also almost 4,000 PECO customers without power. And PPL reports 5,728 outages, most of them in Lancaster County, also west of Philadelphia.

U.S. Vice President Joe Biden says that a state of emergency has been declared for Pennsylvania, a move that helps the state tackle restoring power to hundreds of thousands without it.

Biden made the announcement Thursday in Philadelphia where he was touting the need for more investment in infrastructure. President Barack Obama signed the decree earlier.

Amtrak, meanwhile, says full service between Philadelphia and Harrisburg is being restored today after tracks have been cleared of fallen trees and debris, but riders may see delays of up to one-half hour.

Crews from as far away as Canada and Arkansas have been called in to help out, and officials are comparing the scope of the damage to a hurricane. Some who might not get power back for several days sought warmth — or at least somewhere to recharge their batteries — in shopping malls, public libraries and hastily established shelters.

Pennsylvania Gov. Tom Corbett said after an aerial survey of the storm's aftermath on Thursday that crews put a priority on restoring electricity to hospitals, nursing homes, communications facilities and sewer plants.

“This storm is in some respects as bad or maybe even worse than Hurricane Sandy,” he said during an appearance in the Philadelphia suburbs. He said a shipment of electrical generators from the federal government was on its way to Pennsylvania.

Corbett said he was urging electric utilities “to move as fast as they can, but they have to do it within the parameters of safety.”