The Canadian Avalanche Centre has issued a rarely used extreme avalanche rating, stressing the danger in many of British Columbia's mountains this weekend.
The centre said natural and human-triggered avalanches are certain in the Sea-to-Sky area, as well as the North and South Columbia regions, covering a huge section of B.C.'s southern and southeastern Interior.
Centre forecaster Penny Goddard said the advice for skiers, snowmobilers and other backcountry enthusiasts is pretty straightforward.
"Avoid all avalanche terrain," she said in an interview Friday.
A high-risk rating is in effect in most other areas, as a Pineapple Express, a blast of warm air from the sub-tropics, raises temperatures and dumps rain on recent heavy snow, creating unstable conditions.
Goddard said that recipe is perfect for avalanches this weekend.
"We have a touchy weak layer buried in the upper part of the snowpack, and we have a very intense storm. Snow packs don't like rapid change at the best of times."
She said the combination adds up to a volatile situation.
The risk isn't expected to ease until Sunday.
Three people have died in avalanches in B.C. over the current avalanche season, when the 10-year average is 14.
Goddard hopes this season's lower figure means people are listening to their warnings.
"Even if people weren't heeding our warnings earlier in the season, they may have gotten away with it," she said.
"But now conditions have changed. We have quite a different situation with the snowpack.
"If people don't heed our warnings at the moments, they're much more likely to get involved with avalanches."
The first death occurred in October in northwestern B.C., but the two most-recent fatalities happened last week, in separate incidents involving skiers on southeastern B.C. mountains.