Avalanche Forecast

Issued: Dec 21st, 2012 9:46AM

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

jlammers, Avalanche Canada

Sea To Sky.

Summary

Confidence

Good

Weather Forecast

Saturday: Light snowfall / Light southeast winds / Freezing level at 800mSunday: Trace amounts of new snow / Moderate southeast winds / Freezing level at 1000mMonday: Trace amounts of new snow / Light south winds / Freezing level at 700m

Avalanche Summary

Explosives control on Friday produced storm/windslab avalanches in the alpine to size 2. I would suspect a decline in avalanche activity with forecast light snowfall and decreased winds.

Snowpack Summary

The region has received an impressive amount of new snow in recent days. The snowfall was accompanied by consistently strong to extreme winds that have since backed off leaving windslabs at higher elevations and deep loose snow below treeline.A couple of layers of surface hoar were buried last week in some areas. Test results on the surface hoar suggest an improving bond. A deeper layer of surface hoar from late November is now well over a metre down and no activity has been reported on this layer either. In general, the mid-pack is reported to be well settled and strong. The early November crust/facet combination near the base of the snowpack seems to be dormant. Triggering one of these persistent weak layers has become unlikely; however, the consequences would be significant.

Problems

Storm Slabs

Heavy snow accumulations may have been redistributed by more recent moderate winds creating soft slabs on lee features. Sluffing may also be encountered on steep terrain.

Stay off recent wind loaded areas until the slope has had a chance to stabilize.>On steep slopes, pull over periodically or cut into a new line to manage sluffing.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 4

Valid until: Dec 22nd, 2012 2:00PM