The Canadian Avalanche Centre has upgraded the danger rating to "high" throughout most alpine and treeline regions of B.C. mountains, and is discouraging travel through avalanche terrain this weekend.

The forecasted avalanche risk is high from the northwest coast to the Columbia and Cariboo regions, as well as the Kootenay and Southern Interior regions and the Sea-to-Sky and south coast ranges.

James Foyer, a forecaster with the Canadian Avalanche Centre in Revelstoke, says a number of snowstorms are brewing in the Interior, and the heavy snow falling on top of a weak underlayer could cause large avalanches.

"We're seeing quite a sizable storm coming through today, and that's going to drop quite a bit of snow," said Foyer.

He said inland regions could see 25 to 40 centimetres of snowfall. Foyer said slides could be triggered by the sheer rapid weight loading of the new snow, and by heavy winds that could create wind slabs — weakened snow packs deposited by wind that can avalanche easily.

"We're also worried about a deeper weak layer that's buried in the snow pack," he said.

Two skiers were being rescued in steep North Shore terrain when this photo was taken Thursday night nearby at the Cypress ski hill. (Mike McArthur/CBC)

"That might increase the expected size of avalanche activity, for one, and secondly it might prolong the length of dangers after the storm."

Foyer said the whole of the Columbia region is at particular risk, and backcountry users should be wary about where they go this weekend and in the weeks to come.

"My advice is to select relatively simple terrain," he said.

The avalanche risk has already manifested this week in the East Kootenays, where three skiers from Germany were caught in an avalanche while heli-skiing on Jumbo Glacier on Monday. Two were dug out by others in the group and survived, but a 34-year-old man died in the slide.

Foyer expects the high avalanche risk to last for a number of days in the Cariboo, Columbia, and Kootenay regions.

Ice crust creates Sea-to-Sky danger

In the Sea-to-Sky area and Lower Mainland mountains, a dump of 50 centimeters of snow over the past 24 hours at some higher elevations and high winds are creating even more extreme hazards.

'If we'd had that rescue yesterday in these kind of conditions, those guys would have been popsicles. We'd have found them later on in the year.'—Tim Jones, North Shore Search and Rescue

Tim Jones, speaking for North Shore Search and Rescue, said a weak ice crust is buried under all the new wet snow and the avalanche risk Friday and over the weekend might be the highest it has been in 20 years.

Jones also said avalanches aren't the only dangers backcountry skiers and snowshoers need to prepare for.

"It's a double component in winters operations for us. It's not only avalanche hazard, its falling in these steep gullies," he said.

North Shore Search and Rescue teams undertook a dangerous operation on Thursday, rescuing two skiers who had intentionally gone out of bounds of the Cypress ski area and got stuck in steep terrain.

"The avalanche hazard was considerable. That's not the main issue. The main issue is there is this ice crust from last week, and very steep terrain. This is where the other component of our winter operations is: people falling and getting seriously injured or dying," he said.

Jones said the rescue team has already responded to serious injuries and deaths from falls this year. He also said the pair of skiers that were rescued Thursday were very lucky, and that his team might not have found them if they had gone out-of-bounds Friday instead.

"If we'd had that rescue yesterday in these kind of conditions, those guys would have been popsicles. We'd have found them later on in the year," he said.

Jones says the calmer, sunny weather expected Saturday along the south coast will only bring a false sense of security, and more trouble.

"We're expecting to get calls this weekend," said Jones.