CHICAGO - A severe winter storm dumped snow and freezing rain across the Midwest and mid-Atlantic United States on Sunday, stranding air travelers from Boston to Chicago and causing several traffic deaths.

More than 200 flights were canceled at Chicago's O'Hare International Airport, with remaining flights delayed 60 to 90 minutes because of the icy snow, Chicago Department of Aviation spokeswoman Wendy Abrams said.

JetBlue Airways Corp., still struggling from a service meltdown during last week's ice storm in New York, was among the airlines that canceled flights.

Numerous road closings were reported in the upper Midwest. Wisconsin police reported at least eight traffic-related fatalities, including one accident in southern Wisconsin where a woman's vehicle slammed into a snow plow, killing her and two children.

Thousands of homes lost power. In northern Illinois, utility company ComEd spokesman Jeff Burdick said at its peak, 38,000 customers lost power. Ice on the power lines was a major contributor to the outages, he said.

The National Weather Service said a winter storm warning was in effect from New Jersey to Virginia, while an ice storm warning was in effect in western Pennsylvania.

Moderate to heavy snow was expected through the afternoon for much of the region, but Pennsylvania and Maryland state authorities said all roads remained open.

Snow removal efforts caused flight delays at Dulles and Reagan National airports in the Washington region, Washington Metropolitan Airports Authority spokesman Rob Yingling said.

Bad weather caused flight cancellations from Boston to Milwaukee.

Amtrak service on the East Coast was unaffected by the storm, but service between Washington and Chicago was canceled in part due to the weather, spokeswoman Karina Romero said.

On Saturday, authorities shut down highways and canceled hundreds of flights on Saturday as the storm hammered much of the Midwest.

At least one tornado touched down in Arkansas, while the storm caused a 35-car pileup east of Denver.