Ripe avalanche conditions for parts of B.C. expected to persist this week

A vehicle passes a sign showing an avalanche hazard warning of "considerable" at a parking lot where snowmobilers embark from near Mount Renshaw outside of McBride, B.C., Saturday, Jan. 30, 2016. THE CANADIAN PRESS/Darryl Dyck

A forecaster says ripe avalanche conditions are expected to persist across much of British Columbia for the rest of the week.

Large swaths of the province, stretching from the coast to the Alberta boundary, are under "considerable" or "moderate" avalanche danger warnings.

Tyson Rettie with Avalanche Canada says the conditions are largely a result of a series of storms that have lead to temperature fluctuations and significant amounts of snow at high elevation points.

"We've seen a pattern of a storm every 18 hours or so on the coast for over a week now," Rettie said in an interview Tuesday.

"Every time the storm comes through, it deposits significant amounts of snow, often with strong or extreme winds."

He said storms like these deposit wind and storm slabs, or layers of snow, on mountains.

These deposits bond together on top of existing layers of snow, Rettie said, and when the top slab is stronger than the layer beneath it, the greater the risk for an avalanche.

"We're seeing formation of both storm and wind slabs that are large enough to justify a 'considerable hazard' (warning)," he said.

"Even just the new snow itself can form what we call a storm slab problem or a wind slab problem."

As of Tuesday afternoon, Avalanche Canada had a "considerable hazard" warning covering Vancouver Island, a stretch of coastal B.C. from Powell River to Pemberton in the east, and more areas.

There were also significant areas of the province covered under "moderate hazard" avalanche warnings.

One of these moderate areas is east of Pemberton towards Lillooet, and Rettie noted a few avalanches have been reported in the area over the past week.

On Monday, four backcountry skiers were buried in an avalanche on Ipsoot Mountain north of Whistler, B.C., and a fifth was partially buried.

All were rescued.

B.C. Emergency Health Services said in a statement that three of the skiers were transported to hospital in stable condition, while the other two didn't require hospitalization.

Premier David Eby shared his appreciation for the first responders in a social media post, calling it "an incredible rescue."

Const. Antoine Graebling with the Whistler RCMP detachment said the avalanche was a 2.5 on a five-point scale, which means it was large enough to seriously injure or kill people.

Graebling said his detachment hasn't been notified of any other avalanches. But he and Rettie both said conditions can change daily.

"Each of these storms is bringing a significant amount of precipitation, often warmer temperatures and strong or extreme wind speeds," Rettie said. "The more intense the storm, the higher the danger."

He said the storm pattern is expected to continue near the coast for the rest of this week.

"The timing and intensity of it is a bit uncertain. But at least over the next three days, we're expecting a couple of significant storms to impact the coast," he said.

He encouraged backcountry skiers to check the Avalanche Canada forecasts, which are updated daily, before they hit the slopes. 

This report by The Canadian Press was first published Dec. 24, 2024.