Avalanche Forecast

Issued: Dec 20th, 2014 8:22AM

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

Avalanche Canada triley, Avalanche Canada

New snow and strong winds continue to develop storm slabs resulting in High avalanche danger.

Summary

Confidence

Poor - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

Strong Southwest winds overnight combined with 10-15 cm of new snow and freezing level around 800 metres. Winds becoming moderate Southwest on Sunday as another 5-10 cm of snow is forecast. Winds becoming moderate Westerly on Monday with a few more cms during the day. Drying out and cooling down overnight, followed by another pulse of moisture on Tuesday afternoon.

Avalanche Summary

No new avalanches reported. The forecast new storm is expected to increase avalanche activity over the next few days.

Snowpack Summary

A new storm slab is developing above the recent mix of surfaces which include wind slabs in alpine terrain, hard rain crusts at lower elevations and weak surface hoar crystals. Last week's heavy rain affected southern parts of the region up to alpine elevations, while the far north remained drier and generally has a weaker snowpack. Areas which previously received rain have probably now formed a hard frozen crust. Upper elevation terrain and far northern areas are likely to have wind slabs and large fragile cornices. 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 at higher elevations where precipitation continues to fall as snow.
Cornices may be large and fragile with new growth. Stay well to the windward side of corniced ridges, and avoid travelling beneath cornices.>Avoid freshly wind loaded features.>Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Loose Wet

An icon showing Loose Wet
Rain on snow may occur as the freezing levels rise resulting in loose wet snow releasing from steep terrain features at lower elevations.
Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 21st, 2014 2:00PM