Avalanche Forecast

Issued: Dec 3rd, 2012 9:55AM

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.

jlammers, Avalanche Canada

South Rockies.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Overnight and Tuesday: Light to locally moderate snowfall / Extreme southwest winds / Freezing level at 1500mWedesday: Light snowfall / Strong to extreme southwest winds / Freezing level at surfaceThursday: Trace amounts of snow / Light southwest winds / Freezing level at surface

Avalanche Summary

No recent avalanche observations.

Snowpack Summary

A report from near Harvey Pass tells us that there is about 25 cms of storm snow that is "damp" at treeline and the ski penetration is only about 20 cms. Having said that, recent accumulations have been highly variable throughout the region and more recent strong winds have most likely redistributed surface snow into pockets of windslab at higher elevations. Continued windslab development is expected with forecast weather.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. In short, 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

Forecast snowfall and extreme winds will create new wind slabs and potentially add to the size and reactivity of existing storm slabs. With expected wind values, loading may take place lower on the slope than normal.

Be aware of the potential for wide propagations due to the presence of hard windslabs.>Be alert to conditions that change with elevation.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

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.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 4th, 2012 2:00PM