Avalanche Forecast

Issued: Dec 16th, 2014 7:39AM

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

Avalanche Canada rbuhler, Avalanche Canada

A deeply buried weak layer remains a concern, especially on steep north facing slopes in the alpine. 

Summary

Confidence

Good

Weather Forecast

The high pressure will continue to dominate for Wednesday and Thursday. On Wednesday, expect a mix of sun and cloud and treeline temperatures around -6C. Thursday will be mostly cloudy with light scattered flurries possible (0-2cm). Treeline temperatures should be around -4C. On Friday, the high pressure begins to break down as a weak system pushes into the interior from the coast. Precipitation amounts are forecast to be 3-6mm and freezing levels around 500-700m elevation. Alpine winds are expected to remain light from the SW for the forecast period.

Avalanche Summary

No new avalanches were reported on Monday or by publish time on Tuesday. On Sunday, explosive control produced avalanches to size 2.5. These occurred on N-SE aspects between 2200 and 2500m elevation. Slab depth varied from 30 to 90cm. On Saturday, isolated natural activity was reported up to size 2.5 above 2400m.

Snowpack Summary

A surface crust exists to around 2100m and is generally supportive to skiers. Above this elevation is dry storm snow which is settling out and faceting. A new layer of surface hoar is currently forming on the snow surface. In exposed alpine terrain, strong southerly winds last week may have resulted in variable distribution of the surface snow and the formation of wind slabs. A thick rain crust with facets from early November is buried over 1 m down. Snowpack tests on this deep weak layers are showing improving results, but in some locations these layers are still reactive and has the potential to release large slab avalanches.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
The likelihood of triggering a deep persistent slab has decreased but the consequences remain very high. Be wary of any slopes that did not release during the storms. Heavy triggers such cornice falls may be able to trigger a deep weak layer.
Avoid shallow snowpack areas where triggering is more likely.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

2 - 5

Valid until: Dec 17th, 2014 2:00PM

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