PHILADELPHIA (AP) -- Utility crews worked to restore power to hundreds of thousands of homes and businesses that were still in the dark and cold Thursday after an ice storm knocked out electricity to more than a million customers, damage one official likened to that of a hurricane.
The Northeast's second winter storm of the week dumped more than a foot of snow Wednesday, forcing schools, businesses and government offices to close, snarling air travel and sending cars and trucks sliding on slippery roads and highways - an all-too-familiar litany of misery in a winter where the storms seem to be tripping over each other.
What made this one stand out was the thick coating of ice it left on trees and power lines, causing outages that are expected to linger for days.
Pennsylvania was particularly hard hit, with more than a quarter inch of ice over a large section of the state. At its height, the storm knocked out power to nearly 849,000 customers in Pennsylvania, most of them in the counties surrounding Philadelphia.
"People are going to have to have some patience at this point," Pennsylvania Gov. Tom Corbett said. The governor issued a disaster emergency proclamation, freeing up state agencies to use all available resources and personnel.
About 3,500 workers from as far away as Canada and Arkansas were working with PECO, southeastern Pennsylvania's dominant utility, to restore power, company spokesman Ben Armstrong said. The repair efforts would extend into - and possibly through - the weekend, he said.
While the utility had made headway in restoring power, "some tree limbs and some trees are still coming down on our lines and causing outages for customers," he said Thursday.
"The damage that we are seeing in the field with the number of trees down, not only on lines but blocking roads and more, presents a number of logistical issues," Pennsylvania Public Utility Commission spokeswoman Jennifer Kocher said. "This damage is very similar to what we see during hurricanes."
Officials pleaded with people not to use generators or gas grills indoors after 20 to 25 people in the Philadelphia area were taken to hospitals with carbon monoxide poisoning.
While some homeowners fired up generators, others, like Dave Dixon and his wife, relied on the generosity of others to power them through. They planned to stay with friends overnight Thursday - and possibly longer.
"If we wear out our welcome, we'll get a hotel," said Dixon, whose home in the Philadelphia suburbs went dark at 6 a.m. Wednesday.
In Wyncote, just north of Philadelphia, Hannah Reimer took to Facebook to ask for a kerosene heater and recommendations on where to buy the fuel.
"It worked! Someone from my church, who has power, has a kerosene heater and my husband is picking it up now," she said Wednesday night.
Reimer and her husband then planned to pay it forward, inviting their neighbors to spend the night.
"Our neighbors don't have heat, either," she said. "Or a kerosene heater."
As of Thursday morning, PECO reported more than 429,000 customers without power. FirstEnergy was reporting more than 50,000 customers without power, mostly in central Pennsylvania, while PPL was reporting almost 20,000 in its northeastern Pennsylvania service area.
In neighboring Maryland, where 76,000 customers were in the dark, power companies gave a restoration estimate of Friday. More than 5,000 New Jersey customers also lacked electricity.
The storm was the second-worst in PECO's history - eclipsed only by the nearly 1.8 million that were left without power after Superstorm Sandy in 2012 - with the utility reporting 623,000 outages at one point Wednesday.
Several hospitals were running on backup generators. Most decided to cancel elective surgeries and out-patient testing.
Dr. John Kelly, chief of staff at Abington Memorial Hospital outside Philadelphia, one of the affected facilities, said critical staff needed for any emergencies would be staying overnight. He said the hospital had plenty of fuel and food.
The American Red Cross opened three shelters in southeastern Pennsylvania and stood ready to open more.
"We've been told to be prepared for four to six days. We are gathering staff and volunteers for up to a week," spokesman Dave Schrader said.