Avalanche Forecast

Issued: Dec 4th, 2012 9:33AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Overnight and Wednesday: Light to locally moderate snowfall overnight, easing off by Wednesday morning / Strong to extreme southwest winds / Freezing level at 1600m overnight dropping to surface by Wednesday morning Thursday: Light snowfall / Moderate west winds / Freezing level at 900mFriday: Possibility of clearing / Light southwest winds / Freezing level at surface

Avalanche Summary

Several size 1-1.5 soft slabs were ski cut in the Westcastle area on Monday. They occurred with the recent storm snow on north to northeast facing terrain between 1900 and 2200m.

Snowpack Summary

Recent storm accumulations have been highly variable throughout the region with some reports from the east side of the region indicating storm slabs up to 40cm deep. Warmer temperatures at lower elevations have created moist surfaces that will most likely form a temperature crust with dropping freezing levels. Ongoing light to locally moderate snowfall and strong to extreme winds will create pockets of windslab at treeline and above.The November crust was found to be buried down about 60 cms and was associated with a layer of facets either directly above or below. In general, snowpack data is sparse in this region and significant variations likely exist from one drainage to another. Digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at forecaster@avalanche.ca.

Problems

Wind Slabs

An icon showing Wind Slabs
Forecast snowfall and extreme winds will create new wind slabs and potentially add to the size and reactivity of existing storm slabs. With high wind values, loading may take place lower on the slope than normal.
Be alert to conditions that change with elevation.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Persistent Slabs

An icon showing Persistent Slabs
We have not heard of any new releases on this early season rain crust; however, an avalanche at this interface could be surprisingly large and destructive. This layer may become reactive with warming and/or increased loading.
Choose well supported terrain without convexities.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 5th, 2012 2:00PM