Avalanche Forecast

Issued: Dec 1st, 2012 8:47AM

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

Avalanche Canada Peter, Avalanche Canada

Summary

Confidence

Poor - Due to limited field observations

Weather Forecast

Synopsis: A broad and persistent low pressure center off the BC coast and a steady southwesterly flow over the province will maintain mild temperatures and light to moderate precipitation for the next few days.Sunday: Light to locally moderate snowfall – 10-15 cm, the freezing level is around 800-1000 m, winds are moderate from the south. Monday: Light to moderate snowfall – 5-15 cm, the freezing level is around 1000 m, winds are light to moderate from the southwest. Tuesday: Moderate to locally heavy precipitation, the freezing level should jump to 1800 m.

Avalanche Summary

Recent observations include several natural or explosive triggered avalanches up to size 2 from the north part of the region. The size and likelihood of both natural and human triggered avalanches will increase with forecast snow and wind. We welcome all field observations at forecaster@avalanche.ca.

Snowpack Summary

An additional 20-30 cm of heavy new snow has fallen in the past 24 hours. This dense new snow sits on a crust and/or surface hoar layer, now down 35-50 cm. In addition, expect to find dense wind slabs in exposed lee terrain at and above treeline. Deeper in the snowpack you might find a thin, spotty surface hoar layer about 85cm down. As well, the early November rain crust now sits over 100cm down in most locations (at treeline and above) and may exist in combination with facets. These layers seem to have been unreactive in recent days, but may have the potential to 'wake-up' with additional loading producing surprisingly large and destructive avalanches.The snowpack depth in the alpine ranges from 130-225 cm, and treeline is around 150 cm.

Problems

Storm Slabs

An icon showing Storm Slabs
Continued snow and wind may overload a weak layer of surface hoar and/or a crust, now down 30-50 cm. The size and likelihood of avalanches should increase throughout the forecast period.
Stick to simple terrain and be aware of what is above you at all times.>Be alert to conditions that change with elevation.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
Although the likelihood of a release is low, the consequences of a persistent slab avalanche could be significant. These layers may wake-up with additional loading.
Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Dec 2nd, 2012 2:00PM

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