Avalanche Forecast

Issued: Nov 28th, 2014 7:38AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Storm Slabs.

Avalanche Canada Peter, Avalanche Canada

Heavy rain followed by rapid cooling has helped stabilize the snowpack and lower avalanche danger. Unfortunately it's probably damaged the snow quality too!

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

We’ve seen a big change in the weather pattern from earlier in the week. A push of cold Arctic air from the north is invading the Province all the way down to the South Coast. As the Arctic front passes on Friday afternoon (with an associated trough and moisture) we could see snow flurries all the way to valley bottom. By Saturday morning we could see up to 5-10 cm in the mountains. The Arctic air pushes further south on Saturday leaving us in cold and dry air for the next few days. Treeline temperatures should hover between -8 and -12.

Avalanche Summary

Numerous loose wet and wet slab avalanches up to size 2 were reported near Whistler on Wednesday and Thursday as temperatures spiked and rain fell to 2000 m. Rapid cooling on Friday morning has helped stabilize the snowpack but it may be possible to trigger dense storm slabs higher in the alpine (above 2000 m).

Snowpack Summary

Heavy precipitation gave way to clearing skies and rapidly cooling temperatures early on Friday morning. Most areas saw heavy rain up to at least 2000 m this week. Above this it's possible that dense storm slabs and fresh cornices formed. Where it did rain, the snowpack is probably frozen solid with a dusting of fresh snow on top. The lower elevation snowpack has also thinned significantly. A weak layer of facetted snow on a crust was buried around 50-60 cm deep before the rain. This weakness may have been flushed out or may now be bridged by a solid ice crust; however, there is no new info on this interface so it would be wise to investigate its existence and strength before venturing into bigger terrain.

Problems

Storm Slabs

An icon showing Storm Slabs
Rain saturated the snowpack up to 2000 m and has now frozen solid. If we see a decent amount of snow on Friday evening (with wind) we might see new wind slabs form.
Be alert to conditions that change with elevation.>Early season hazards such as rocks, trees and stumps are still visible.>Cold temperatures may have stabilized the snowpack, but watch out for isolated fresh wind slabs.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Nov 29th, 2014 2:00PM