Avalanche Forecast

Issued: Dec 21st, 2014 7:30AM

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

Avalanche Canada triley, Avalanche Canada

Avalanche danger is expected to remain elevated as forecast stormy weather continues.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

5-10 cm of snow combined with moderate Southwest winds overnight and freezing levels hovering around 700 metres. A weak ridge of High pressure is forecast to dry out most of the province, but it may not have much of a cooling effect in the Northwest. Some Pacific moisture may get bumped up above the ridge resulting in 3-5 cm of snow during the day on Monday. The next strong pulse of Pacific moisture should hit the coast sometime early Tuesday morning bringing up to 25 cm during the 12 hour period between 4 AM and 4 PM. Very strong Southwest winds are expected with this next storm and freezing levels should remain at about 700 metres. The storm should continue into Wednesday bringing another 15-20 cm combined with strong Southwest winds.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

A new storm slab has developed that is about 50-70 cm thick at higher elevations. Strong Southwest winds have transported snow into windslabs that may be about 100 cm thick. Rain up to about 800-900 metres elevation may have resulted in loose wet avalanches where that rain fell on snow from earlier in the storm. Cornices are expected to be large and fragile due to new rapid growth. Deeper in the snowpack, weaknesses such as the mid-November crust-facet layer still exist. Avalanches at this interface have become unlikely, although the consequences of a release remain high. This layer may be more sensitive to triggering in steep, unsupported high alpine terrain, or in the far north of the region.

Problems

Storm Slabs

An icon showing Storm Slabs
The new storm slab is expected to continue to develop due to incremental loading over the next few days. Pockets of windslab are expected to be easy to trigger. Cornices may be large and fragile from recent rapid growth.
Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>Avoid freshly wind loaded features.>Cornices may be large and fragile with new growth. Stay well to the windward side of corniced ridges, and avoid travelling beneath cornices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Valid until: Dec 22nd, 2014 2:00PM