Scores of vehicles got stuck on Interstate 5 after a “bomb cyclone” – a supercharged winter storm caused by a rapid drop in atmospheric pressure – dumped up to 1.2m of snow in mountainous areas of the Pacific Northwest.
“We’ve been white knuckling it for the last four hours and sliding around the road,” said Lisa Chadwick after she stopped in Bend, Oregon, driving north from San Francisco.
She had snowchains for her two-wheel drive car but did not know how to put them on.
The US Midwest was also hit hard by a storm that clobbered Denver on Tuesday, with airports in Minneapolis and Chicago suffering hundreds of delays and cancellations.
The storms hit on one of the busiest travel days of the year, with a near-record 55 million Americans set to journey at least 80km for Thanksgiving today, according to the American Automobile Association.
After parts of Colorado got up to 75cm of snow on Tuesday, Minneapolis was expected to get as much as 30cm as the system slid east, said Brian Hurley, a meteorologist with the National Weather Service in College Park, Maryland.
The storm, which is packing high winds, will move across upper Michigan and upstate New York toward central Maine, which could get 15 to 25cm of snow, the Weather Service forecast.
Lots of honking
On the West Coast, heavy rain threatened flash floods from San Diego to Los Angeles.
Los Angeles International Airport told domestic passengers to arrive three hours early as it expected 238,000 passengers and 113,000 vehicles.
“There has been definitely lots of honking, lots of near accidents that I’ve seen, for sure,” Daniel Julien, a 24-year-old paralegal from Pasadena, said after making it to the airport.
A silver lining was that rain doused the Cave Fire in Santa Barbara County, which charred 1,810 hectares of brush and woodlands.
But it brought evacuation warnings to thousands of residents in Santa Barbara suburbs for possible mudslides on fire-charred hills.
Across the country, 4,083 flights were delayed, and 148 were cancelled into or out of the United States by 6.30pm ET, with Chicago’s O’Hare International Airport tallying the most, according to FlightAware.com.
“There are apocalyptic storms all over the country and 80kph winds! Why would things not be the worst,” said a Twitter user going by the name of Abigail H, who was leaving O’Hare.
“Anyway pray 4 me.”
The East Coast was largely unscathed, but wind gusts of up to 64km forecast for this morning threatened to sideline the Macy’s New York City Thanksgiving parade’s 16 giant balloons for safety reasons.
Organisers have said they will make the decision today whether to go ahead.