Of the nearly 64 million Americans traveling more than 50 miles from home this holiday season, some 17 percent were on the move today - making it the busiest travel day of the holiday season.
Conditions improved Wednesday but highways were still dangerously slippery in some areas. At least 23 highway deaths had been blamed on the weather.
More snow fell in the Midwest, where the National Weather Service said up to 4 inches was possible in Chicago. The Northwest faced more snow and sleet, with up to 20 inches possible in the Cascade range in Washington, and icy, wet weather spread over the Northeast.
In Seattle, frustrated passengers encountered more than just the worst wintry weather the city's seen in about 10 years, CBS News correspondent Kelly Wallace reports. De-icing fumes got into the ventilation system of an Alaska Airlines plane headed for Burbank, Calif. 26 people had to be treated, but none was seriously hurt and the plane did make its journey to Burbank.
But despite more snow falling in the Seattle area, operations at Sea-Tac Airport were back to normal Wednesday, said spokeswoman Terri-Ann Betancourt. She said the last of thousands of passengers who were stranded by weekend cancellations were gone by Tuesday, and the only flight cancellations were caused by delays or cancellations at other airports.
About 500 travelers had to spend the night at Chicago's O'Hare International, the nation's second busiest airport, after stormy weather canceled more than 500 flights Tuesday, said Chicago Aviation Department spokeswoman Karen Pride. Some slept on cots, some on the floor or across waiting-room seats, and at least some face the prospect of spending Christmas Eve at O'Hare.
Delays averaged an hour and a half in Chicago, close to two hours in San Francisco, and three hours in Newark where Lester and Melissa Jenkins are among the thousands trying to make it to their families in time for Christmas, Wallace reports.
"We were supposed to go out to dinner tonight. So I guess we'll have dinner in the airport," Melissa Jenkins said.
Newlyweds Tommy and Siobhan Costello were at O'Hare on Wednesday gearing up to spend their second night stranded in an airport hotel en route to their honeymoon in San Diego. They arrived from their native Ireland on Tuesday, but the weather disruptions meant earliest flight out they could get was Thursday.
"This was supposed to be a pit stop," said Siobhan Costello, 30. "But there's nothing you can do."
At O'Hare's American Airlines terminal, Paul Fustini waited with a bag of food for his daughter Sara, who was trying to get home to Orlando, Fla. Her flight was canceled Tuesday and she finally got a flight for Thursday afternoon.
"She wishes I would have brought a toothbrush," Fustini said.
More than 100 flights were canceled at O'Hare on Wednesday. On Tuesday, cancellations totaled more than 500.
Over the past few days, both coasts have seen their share of record snowfall, reports Early Show weather anchor Dave Price. A winter storm dumped snow throughout Arizona Tuesday and another round is expected to last through Christmas Day.
"The airlines are dealing with nothing but unhappy customers," said Mike Conway, spokesman for Detroit's Metropolitan Airport, where delays were reported in departures and arrivals because of conditions elsewhere in the country.
The weather service posted winter storm warnings and advisories for large parts of the West, plus parts of the Midwest and the Northeast.
Driving conditions were still tough in Oregon's Portland metro area, where many side streets were still clogged with snow and motorists were required to have tire chains, unless they had four-wheel drive and tires designed for hazardous weather. More snow fell in the region Wednesday.
Oregon's state's largest utility, PGE, said it had restored service to 265,000 customers since the stormy arrived Friday, but 47,000 were still blacked out Wednesday.
Across Massachusetts, icy roads caused numerous accidents Wednesday morning, and state Trooper Thomas Murphy Interstate 495 in Middleborough and Wareham was closed because of wrecks.
"It looks like all areas should see a white Christmas," meteorologist Dave Kook said from the weather service office in Oakland County's White Lake Township. "There's enough snow on the ground that it won't all melt away with the rain."
Amtrak also reported improvement Wednesday. Trains out of Chicago and elsewhere were leaving on time - or relatively close to it - unlike Tuesday when several trains were canceled and some 600 furious travelers waited for as much as 22 hours for delayed trains at Chicago's Union Station, spokesman Marc Magliari said.
Also Wednesday, an in northern Utah. The Utah Avalanche Center warned people not to venture into the backcountry.