Repair crews and homeowners still faced a mixture of snow, sleet and light rain that fell across parts of north Texas and central Oklahoma during the morning.
Temperatures have been rising and may get close to 40 on Thursday, which should help some of the ice, but by late Friday, however, another storm could bring 2 to 4 inches of snow to parts of the region.
Ice up to one and a half inches thick has glazed much of the central Plains and Midwest this week. At least 27 deaths, mostly due to traffic accidents, have been blamed on the storm system since it developed last weekend.
Outside that affected area, forecasters said more snow, sleet and freezing rain could develop Wednesday across the northern Ohio Valley and into New England.
All told, since the storm hit over the weekend, an estimated half a million customers are still without power across Oklahoma, reports CBS News correspondent Hari Sreenivasan.
Businesses are closed, traffic lights have turned to four way stops.
"We're relying on people to look after each other," Oklahoma City Mayor Mick Cornett said. "At the end of the day, this comes down to the strength of your people. ... People who have electricity ought to be sharing it with people who don't."
"Crews of linemen are coming in from New Mexico, Louisiana, and Texas, returning the favor after crews here went down from Louisiana and Mississippi after Hurricane Rita and Katrina," reports Doug Warner of CBS affiliate KWTV in Oklahoma City.
Neighboring states from Missouri to Kansas to Iowa are thawing out and cleaning up as well, adds Sreenivasan
Around 228,000 customers were still blacked out in Missouri, Kansas, Iowa, Illinois and Nebraska. Kansas' tally had risen -- to 130,000 on Wednesday, up 15,000 from Tuesday -- as rural electric cooperatives reported in and falling branches brought down more power lines.
"We have a lot of trees down ... lots of infrastructure that needs to be put up," said Al Butkus, a spokesman for the utility Aquila Inc. in Missouri. "This is not going to be quick."
Most people decided to stay home and bundle up rather than go to shelters.
"We've got kerosene lamps and a fireplace," said Charita Miller of Oklahoma City. "We're OK. We can't watch TV. Oh well, you can't have everything. It's just me and my husband. My husband said `There's food in the freezer."'
Sonya Kendrick, who spent Monday night at one of several American Red Cross shelters set up in Oklahoma City, said a tree ripped the electrical box off the side of her house, and she needed a warm place for her three children.
"When I got in here yesterday, I was totally distraught. I was like 'Why me? Why me of all people?' I look at it this way, too: I'm not the only one," Kendrick said Tuesday. "There's other people here that I got to know in less than two days, literally. All of them have been through the same thing, and everybody here just understands everybody."
Officials in Missouri, Kansas and Oklahoma had declared states of emergency. President Bush declared a federal emergency in Oklahoma on Tuesday, ordering government aid to supplement state and local efforts.
The 27 deaths blamed on the weather include 16 in Oklahoma, four in Kansas, three each in Missouri and Michigan and one in Nebraska.