VANCOUVER, British Columbia — Snow and Arctic winds blasting across parts of Canada’s British Columbia and into the northwestern U.S. temporarily halted all flights at Vancouver’s airport Tuesday during one of the busiest travel periods of the year.

Forecasters warned of whiteout conditions in some parts of the Pacific coast province as life-threatening cold from the Arctic air mass was expected this week to sweep as far as the Southern U.S. during the peak winter holiday travel season.

As much as 30 centimeters (12 inches) of snow accumulated on parts of southern Vancouver Island while Metro Vancouver grappled with up to 25 centimeters (10 inches), the Ministry of Transportation said. Environment Canada forecast that as much as 10 more centimeters (4 inches) would fall before conditions ease in Vancouver.

Vancouver International Airport temporarily suspended all incoming and outgoing flights early Tuesday, holding departing aircraft at their gates and stranding passengers aboard some arriving flights for hours.

The airport said it was dealing with “mass cancellations” and working to “deplane passengers safely” after the snowfall had an “unprecedented” effect on flights, airport spokeswoman Megan Sutton said in an emailed statement.

“Passengers who are expecting to fly today and this week are advised to check with their airline directly on the status of their flight,” she said, urging people to stay away.

The airport was crowded with stranded travelers, many sitting or sleeping on the floor.

Surrey, British Columbia resident Mary Guzman said she and her family boarded a flight to the Philippines at 9 p.m., hoping to enjoy Christmas with relatives there. But after spending the night on the tarmac on the grounded plane, they were told the flight had been canceled.

“The night was not easy, especially (because) we have a four-year-old daughter and an 88-year-old senior,” said Guzman, pointing to her toddler and elderly mother. “We didn’t sleep at all on plane. But that’s the thing, we understand it’s for our safety. So I continue to pray that we can leave tonight.”

Toronto resident Adam Abbi said he had been at the airport since Monday afternoon, after his flight home was delayed, then canceled.

He said he got through a long and sleepless night thanks to “espresso, two shots.”

Residents were urged against non-essential travel. For those who must drive, the Insurance Corp. of B.C. recommended packing emergency kits including jumper cables, warm clothes and shovels.

Social media posts showed vehicles spinning out or stuck on the sides of roads, and some cyclists venturing out on two wheels.

The snow snarled traffic via the Alex Fraser Bridge and Massey Tunnel, two major Metro Vancouver bottlenecks, and drivers were urged to use alternative routes.

The Coquihalla was temporarily closed southbound due to multiple vehicle incidents that began clearing just after noon.

BC Ferries also canceled all morning sailings between the Mainland, Vancouver Island, the Sunshine Coast and southern Gulf Islands because of poor visibility and difficulty reaching ferry terminals, while police in Abbotsford, east of Vancouver, reported whiteout conditions along Highway 1 through the Fraser Valley.

The universities of B.C. and Victoria, as well as Simon Fraser University and the B.C. Institute of Technology, all cancelled exams or classes scheduled for the morning and expected to update afternoon plans later in the day.