Avalanche Forecast

Issued: Dec 14th, 2014 8:32AM

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

Avalanche Canada swerner, Avalanche Canada

Recent avalanches have failed on a deeply buried weak layer. Although the chances of triggering a deep slab are dropping, the consequences remain high.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

A mix of sun and clouds on Monday with forecast alpine temperatures near -2.0 and light SE ridgetop winds. As the ridge starts to break down Tuesday, we'll see a series of weak storm systems mainly confined to the coast and traveling northward. These systems will bring light snow accumulations as the freezing levels hover around 1000 m. Outflow winds, bringing cooler dry air will persist.

Avalanche Summary

No new observations reported for Sunday. A natural cycle up to size 3 was observed throughout last weeks storm. These included wind slabs and storm slabs, primarily at alpine elevations; and loose wet and wet slab avalanches at treeline and below. Notably, some of these events failed on a crust /facet layer buried in late November and were more than 1 metre deep Thursday and Friday. On Saturday, a vehicle remotely triggered yet another slab 1m deep, on a north-facing slope in the alpine.

Snowpack Summary

The recent prolonged storm dropped 100-200 mm of water, with fluctuating freezing levels bringing rain at times to alpine elevations. Snow also accumulated above treeline, leading to deep wind slabs. Storm and winds slabs may remain problematic for a day or two. However, my bigger concern is a buried crust/facet layer which formed in November and is now down 1-2 m. This woke up with the recent storm snow loading and has the potential for deep slabs and wide propagations, and does not inspire huge confidence. The likelihood of triggering this beast is dropping, however the consequences remain high.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs are likely to exist on leeward slopes and terrain features. Wind slabs could fail on a deeply buried crust layer, initiating a surprisingly large avalanche. Rider triggering is possible.
Use caution in lee areas in the alpine and treeline. Avoid these features by traveling on ridge tops or ribs.>Avoid convexities or areas where the snowpack depth transitions from thin to thick.>

Aspects: North, North East, East, South East, South, South West.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Valid until: Dec 15th, 2014 2:00PM

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