More snow fell Wednesday in the Midwest, where the National Weather Service said up to 4 inches was possible in Chicago. The Northwest faced more snow and sleet early Wednesday, with 8 inches of snowfall expected in Spokane. And more snow and ice spread over the Northeast.
"We're seeing quite a bit of messiness out there," said weather service meteorologist Ed Shimon, who's been at work at the agency's Lincoln, Ill., office for six straight days, a period when the state has seen snow, ice and subzero temperatures. "It's something different every day - never a dull moment."
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.
Only about a dozen flights had been called off at O'Hare early Wednesday, but the Federal Aviation Administration reported delays there and at Cleveland and Newark, N.J.
Travelers relying on Amtrak train service also ran into weather-related delays caused by snow-packed track switches and other cold-related problems across the country.
Around 600 train travelers in Chicago waited for up to 22 hours before finally boarding their delayed trains - the Lake Shore Limited, which was bound for New York, and the Seattle- and Portland, Ore.-bound Empire Builder.
"It's spoiled our Christmas, sure," 73-year-old Don Seifert said after he and his wife abandoned hope of spending the holidays in New York with their son and his family.
However, crowds of stranded travelers at Seattle-Tacoma International Airport were drastically reduced Tuesday, some Amtrak trains and Greyhound buses in the Pacific Northwest were running and motorists in the region found easier going Tuesday.
Greyhound officials opened service on Interstate 5 from Portland to Seattle and from Seattle to Spokane but not east of there. Portland to Boise service remained suspended.
Amtrak said it is moving passengers from Eugene to Portland by bus, from Portland to Seattle by train, and from Seattle to Vancouver, British Columbia, by bus.
The reprieve was to be short-lived. The weather service posted winter storm warnings and winter weather advisories for wide areas of Washington and Oregon, although slightly warmer temperatures and rain were expected across western Washington later on Christmas Eve.
Many roads across northern and central Indiana were ice-covered Wednesday morning as temperatures slowly rose above freezing. Indiana State Police reopened a 30-mile stretch of Interstate 69 northeast of Indianapolis after closing it for about four hours due to ice.
The National Weather Service warned residents of northern Indiana about a significant flooding threat this weekend because of expected heavy rains later in the week and a rapid snow melt.
At least 12 people died in car crashes on rain and ice-slickened roads Tuesday - two in Missouri, two in Kansas, one in Oklahoma, four in Kentucky, one in Ohio and two in Indiana.
Associated Press writers Tim Klass in Seattle and Tim Fought in Portland, Ore., contributed to this report.