Avalanche Forecast

Issued: Nov 28th, 2014 7:44AM

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

Weve 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

Rapid cooling has reduced the likelihood of triggering avalanches this weekend. A size 2 slab avalanche was observed off the east side of Joffre Peak in the Duffy Lake area on Wednesday morning. This slide triggered several loose wet sluffs lower on the slope that ran quite far. The observer also reported several older crowns from alpine terrain that probably release overnight or early that morning. Please let us know what you're seeing out there at forecaster@avalanche.ca.

Snowpack Summary

There are few actual observations from the region to start the season. This is based mostly off weather station data and the weather forecast. Most areas experienced heavy rain this week up to 2000 m, or even higher. Higher elevations may have continued to see wet snow accumulate, a possibly a lot of it. Rapid cooling early on Friday has probably left a new rain crust near the surface, but in some areas it's already buried by 10-15 cm of light snow. A weak layer of facetted snow on a crust may be lurking deeper in the snowpack. However, it's possible this weakness was 'flushed' out with the recent heavy precipitation. There's limited recent info on this weakness so I recommend digging to confirm the existence of the layer, its depth, and to test its strength.

Problems

Storm Slabs

An icon showing Storm Slabs
Heavy rain followed by rapid cooling has reduced the likelihood of triggering storm slabs, but watch for fresh slabs forming if we see a good pulse of snow late Friday.
Avoid freshly wind loaded features.>Be alert to conditions that change with elevation.>Cold temperatures may have stabilized the snowpack, but watch out for lingering instabilities in alpine terrain.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

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