Avalanche Forecast

Issued: Jan 8th, 2012 9:09AM

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

Jlammers, Avalanche Canada

Sea To Sky.

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Monday: 30-40cm of snow is expected Sunday night and into Monday. / Moderate to strong southwest winds / Freezing level dropping from 1500m to 600m throughout the day Tuesday: Mix of sun and cloud with light flurries / light to moderate northwest winds / Freezing level at surface Wednesday: Clear / light to moderate north winds / Freezing level at surface

Avalanche Summary

There have been no new avalanches to report in the last 48 hours.

Snowpack Summary

At treeline, the snowpack sits at about 260cm.In the upper snowpack, weaknesses within and under last week's 80cm of storm snow have gained significant strength. Expect significant new wind slab and storm slab development with forecast weather.Persistent weaknesses remain a concern in the many parts of the region. In the mid-pack, facets with an associated crust (resulting from the early December dry spell) at treeline and alpine areas are probably down well over a metre in most places. This layer still seems to be reactive, particularly in shallow areas or terrain with variable snow depths (cross-loaded features, moraines). In the lower snowpack, basal facets from early november should also be on your radar. They may just be waiting for the right trigger (heavy storm loading, cornice fall, step-down avalanches). Any activity on either of these persistent weaknesses would be highly destructive in nature.

Problems

Wind Slabs

Stiff and deep reactive windslabs are expected to develop at treeline and in the alpine with forecast wind and snow

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Storm Slabs

The forecast snowfall with create a new storm slab at all elevations. Triggering will be likely, especially during periods of intense precipitation

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

More likely to be triggered from thin slab areas (ie: moraines, cross-loaded features), from heavy triggers like cornice falls, or from storm or wind slab avalanches stepping down to deeper weaknesses.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Jan 9th, 2012 8:00AM