Avalanche Canada pgoddard, Avalanche Canada

Sea to Sky Avalanche Forecast

Dec 18th, 2012 9:22AM

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

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Wednesday: Strong S winds. Alpine temp -8. Heavy snow.Thursday: Light to moderate SE-SW winds. Alpine temp -9. Moderate to heavy snow.Friday: Light to moderate SE winds. Very light snow.

Avalanche Summary

Numerous size 1-1.5 soft slabs and loose snow avalanches were triggered naturally and by skiers on Monday. In some wind-affected areas, soft slabs were propagating widely.

Snowpack Summary

Expect new storm slabs and wind slabs to form on a widespread basis on Wednesday. A previous 40-80 cm of recent storm snow has been shifted into wind slabs on slopes lee to SE to SW winds. A couple of layers of surface hoar were buried last week in some areas. Snowpack test results on the surface hoar suggest an improving bond. The mid-pack is reported to be well settled and strong. A deeper layer of surface hoar from late November has been found intact or decomposing in some locations down a metre or more. The early November crust/facet combination near the base of the snowpack seems to be dormant. Triggering one of these persistent weak layers from a shallow snowpack area, or with a heavy trigger, remains possible.

Problems

Storm Slabs

An icon showing Storm Slabs

Likelihood

Very Likely - Likely

Expected Size

1 - 5
Heavy snow and strong winds are likely to create widespread instabilities. Be alert for wind slabs behind ridges and ribs. Soft slabs or sluffs can be found on steep terrain sheltered from the wind.
Travel in avalanche terrain is not recommended without advanced training and extensive experience.>Stick to simple terrain and be aware of what is above you at all times.>Storm slabs may trigger deeper instabilities.>

Aspects:

All aspects.

Elevations:

All elevations.

Valid until: Dec 19th, 2012 2:00PM