A major storm forecast to dump up to 50 centimetres of snow on already dangerous mountain slopes in southern British Columbia and southwestern Alberta, has closed the Trans-Canada Highway in B.C. because of avalanche risk.

Highway 1 is expected to remain closed in both directions between Craigellachie and Revelstoke because of the high avalanche danger at least until 10 a.m. Friday, according to the DriveBC website.

On the Trans-Canada and Coquihalla highways, 15 to 25 centimetres of snow is expected to fall on mountain passes, with 30 to 50 centimetres expected at the Coquihalla Summit, prompting special warnings for drivers to be prepared for closures and extreme winter conditions before setting out.

At the Whistler-Blackcomb ski resort, the storm is forecast to dump up to 21 centimetres of much-needed snow on the slopes. So far this season, ski resorts across southern B.C. have had the least snow recorded in years, with some yet to open.

Unstable slopes trigger concerns

Karl Klassen, the warning services manager for the Canadian Avalanche Centre in Revelstoke, B.C., said avalanche forecasters are concerned that snowmobilers, skiers and snowboarders heading into the backcountry might be lulled into a false sense of security after a few years of stable conditions.

"We are asking people to be a bit more cautious this year than they were last year," Klassen said Thursday.

"Take on smaller slopes that aren't as complex, slopes that aren't as steep, especially during this storm over the next few days. The weekend is going to be a real challenging time.

"The layers of snow are just waiting for the wind and snow to overload them and cause avalanches," he said.

"If it doesn't happen naturally, it is almost certainly going to happen if a skier or a snowmobile touches the wrong place on the wrong slope at the wrong time."

The avalanche risk in the alpine and treeline zones across the region varied from high to considerable Thursday before the storm.

Klassen said people venturing out need to check local avalanche and weather conditions. They should also carry emergency equipment such as transceivers, probes and shovels and be properly trained in how to use them.

Being less aggressive on the slopes in such conditions could make all the difference, he suggested.

"We want to remind people that this year isn't like last year or the year before. You need to be really doing your homework and ensure you are approaching slopes with caution to make sure you don't trigger one of these weak layers that are hidden from view right now."

Dangerous season already

There have been three serious avalanches in the Golden, B.C., area in the last two weeks, including one on Dec. 20 that killed an Edmonton man who was snowboarding out of bounds at a ski resort.

In another avalanche on Dec. 29, two of four people backcountry skiing near the Alberta boundary were injured, one of them seriously. The four were flown out of the area the next day by helicopter.

There was another avalanche in the area on Dec. 31 in which a person was seriously hurt.

Klassen said forecasters hope that the recent avalanches don't mark the start of a trend this season.

Google Map: Revelstoke, B.C.


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With files from The Canadian Press