Avalanche Forecast

Issued: Dec 15th, 2012 8:25AM

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

istorm, Avalanche Canada

Northwest Coastal.

Summary

Weather Forecast

Synopsis: The next Low pressure system is tracking south of the region so the NW is setting up for little precipitation, light wind, and continuted cool temperatures over the next few days.Sunday: Light to moderate SW wind with light & localized convective snow squalls and alpine temperatures around -8C and below freezing temperatures right to the valley.Monday & Tuesday: Light SW or W wind, light & localized snow flurries, continued cool temperatures with below zero at all elevations.

Avalanche Summary

Near Stewart only small loose slides from sttep cliffy terrain; otherwise no new naturals reported. Near the Shames backcountry evidence of a mid-week natural cycle of small (size 1 to 1.5) slabs was reported. No new recent reports from Terrace were received.

Snowpack Summary

The storm forecast for today (Saturday) didn't seem to make it onshore with any great punch, only light accumulations reported away from the coast. The upper snowpack should be mostly slowly settling powder with pockets of windslab or wind affected snow in exposed areas. Below this, near Shames at least, there may be some patchy surface hoar. Deeper in the snowpack professionals continue to monitor a crust down near the ground. It seems this problem is confined toÂ alpine areas and likely needs a large trigger and / or a shallow snow pack feature to trigger.

Problems

Storm Slabs

Storm snow instabilities are possible on steeper slopes. New windslabs may have formed behind ridges & ribs, primarily on north and east facing terrain.

Assess start zones carefully and use safe travel techniques.>Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 5

Deep Persistent Slabs

Deeply buried weaknesses exist, and the incoming storm could test their strength. Dropping cornices or smalller surface slides could step down.

Avoid shallow snowpack areas where triggering is more likely.>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

3 - 7

Valid until: Dec 16th, 2012 2:00PM