A wide-spreading cold snap has hit large parts of the country since last Sunday, hampering Christmas week travel nationwide with flight delays and road closures, authorities said Monday.
At the Seattle-Tacoma International Airport in Washington state, two major carriers, Alaska Airlines and Horizon Air, suspended service last Sunday, leaving many travelers trapped there, according to the Federal Aviation Administration, or FAA.
Some travelers may have to wait until midweek or later to get flights out of the airport.
To the south, travelers also spent the night in the Portland airport of Oregon, after airlines canceled many flights last Sunday.
With more than 28 cm of snow on the ground Monday morning in Portland, vehicles on all Portland roads were required to have snow chains.
Another winter storm was expected to move into the Northwest from the Pacific Ocean late Tuesday.
On the east coast, air travelers heading for Newark-Liberty International Airport in New Jersey faced delays of almost two hours on Monday, the FAA said.
In the New York state, more than 209 km of highway were shut down for a while Monday morning after dozens of vehicles slid off the icy roadway.
Police agencies in western New York were advising motorists not to leave home.
Schools were closed Monday in Boston, Massachusetts, as icy roadways prevented buses from operating.
Car travel is now often dangerous in parts of the Northern United States.
Drivers blinded by blizzard conditions drove into a 30-vehicle pile-up on Interstate 94 in western Michigan's Berrien County last Sunday afternoon.
Dozens of other vehicles also were involved in a series of other nearby wrecks, including one that killed a 31-year-old Illinois man, police said.
More snow will be dumped Monday on the Great Lakes region and New England, the National Weather Service, or NWS, said.