"We've had two beautiful, sunny days in Maine and the ice isn't going anyplace," said Lynette Miller, spokeswoman for the Maine Emergency Management Agency. "They're very concerned about more weight coming down on trees that are already compromised by ice."
Central Maine Power, with more than 24,000 customers still in the dark early Thursday, hoped to get power back for most by the end of the day but acknowledged that some will still be without electricity on Friday. More than 100,000 were without power at the storm's peak.
More snow was forecast Thursday for Maine and parts of Michigan, and frigid temperatures were expected to keep ice from melting off power lines and tree branches, posing new risks for outages.
(Read more: After Christmas: Here come the deals
From 2 to 6 inches of snow could fall in parts of Maine.
Ashley Walter, 27, was still hunkered down with her husband, Jacob, and their month-old daughter, Leah, at a shelter set up in a school in Litchfield, Maine. The family lost power Saturday, got it back temporarily, then lost it again Sunday and have been without since.
Despite the challenge of being forced out of the house, especially at Christmas, the family was staying positive.
"It's definitely kind of strange but we're hanging in there," Ashley Walter said Wednesday. "We did our Christmas together last night. I packed little stockings and gave them to my husband, sisters and my daughter."
(Watch more: Holiday shipping issues trigger consumer complaints)
Trudy Lamoreau was supervising the emergency shelter where about 25 people stayed Tuesday night. Lamoreau, who's also the town manager, said they warmed the shelter with generators until the school got power back late Tuesday night.
"People are doing quite well considering the circumstances," she said.
In Michigan, about 105,000 homes and businesses were still without power early Thursday, down from more than 500,000 at the storm's peak. CMS Energy said some of its nearly 90,000 customers still offline may have to wait until Saturday to get power back.
With no electricity at their home, Jill Ghantous and her family from Swartz Creek, Mich., opened their Christmas presents at a hotel in Genesee County's Grand Blanc Township, southeast of Flint.
The family members took the Christmas stockings from their home and hung them from a dresser in the hotel room.
They also bought a small tree for the room, said Ghantous, whose children are 10 and 6.
"I guess we can kind of pull Christmas out of nothing," Ghantous told MLive.com. "You just get resourceful and try to make it the best you can."
So far, authorities blame the storm for 27 deaths; 17 in the U.S. and 10 in Canada, including five who apparently died from carbon monoxide poisoning.
In Canada, more than 101,000 customers in three provinces—Quebec, Ontario and New Brunswick—were without power Thursday morning. There were almost 54,000 customers without power in Toronto, down from 300,000 at the height of the outages.
—By The Associated Press