* More than 1,000 flights canceled in and out of Chicago
* Snow and ice make driving difficult in several states
A blizzard dumped heavy snow on the midwestern United States, disrupting highway and air travel on Tuesday as it moved east toward the Ohio Valley and the mid-Atlantic states.
More than 1,000 flights were canceled in and out of Chicago's O'Hare and Midway airports and nearly 100 more were canceled in and out of Minneapolis-St.Paul International Airport, according to the FlightAware.com flight tracking service.
Heavy snow and patches of ice made driving difficult along the highways in parts of North Dakota, Minnesota and northwest Illinois on Tuesday. Chicago was forecast to get 6 to 10 inches (15 to 25 cm) of snow.
The storm was expected to move eastward over the Ohio Valley and then the central Appalachians and mid-Atlantic states on Wednesday, hitting Washington with its biggest snowfall of the winter, the National Weather Service said.
The snowstorm roared into North Dakota on Monday, blowing snow and drifts up to 3 feet (0.9 meter) high. The North Dakota Transportation Department urged people to stay off the roads across the northwestern part of the state.
But the state took the latest storm in stride.
"It's a normal late winter storm for us," said Adam Jones, a meteorologist with the National Weather Service in Bismarck.
The storm was expected to dump heavy snow along the Minnesota and Wisconsin border, with up to a foot (30 cm) in the far southeastern corner of Minnesota, before heading across southern Wisconsin and into Illinois.
In a separate storm, heavy snow and high winds were blamed for two major traffic accidents in the Colorado mountains, near the ski resort of Vail, involving more than 50 vehicles.
Three people were hospitalized from a 25-vehicle chain- reaction crash that closed a stretch of Interstate 70, the Summit County Sheriff's Office said in a statement. "None of the injuries were reported to be serious," the statement said.
A second pile-up about 17 miles (27 km) away on the same interstate involved 29 vehicles, with no reported injuries, the sheriff's office said.