Avalanche Forecast

Issued: Jan 4th, 2013 9:44AM

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

Avalanche Canada pgoddard, Avalanche Canada

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Saturday: Moderate SW winds. Alpine temperature -5. Around 5-10 cm snow.Sunday: Light to moderate SW winds. Alpine temperature -5. No precipitation.Monday: Light SW winds. Alpine temperature -7.  Very light snow.

Avalanche Summary

A cycle of natural and human-triggered (including remotely-triggered and helicopter-remote) avalanches of up to size 2.5 was observed across the region. Storm snow is propagating easily on buried surface hoar. Near Bear Pass, several wind slabs failed naturally on north aspects, possibly failing on facets. Skiers were witnessed going for rides in the Shames Backcountry, highlighting the surprising reactivity of the snowpack.

Snowpack Summary

20-60cm of recent storm snow is bonding poorly, with very touchy reactivity on buried surface hoar, especially near Terrace. This layer is being triggered naturally or remotely and propagating widely. Recent strong southwesterly to southeasterly winds have also set up wind slabs in many exposed lee areas. There are two surface hoar layers in the upper snowpack. The upper one formed at the end of December and is buried approximately 30 cm below the surface. This one is particularly reactive at present. The lower one formed at the beginning of December and is buried approximately 90 cm below the surface. Hard, planar compression tests have been reported on this layer. Near the base of the snowpack, a crust/facet layer continues to give hard, sudden results to no results in snowpack tests. This weakness is unlikely to be triggered by a single person, but it remains possible with a very heavy load (e.g. cornice fall) or from a thin-spot trigger point.

Problems

Storm Slabs

An icon showing Storm Slabs
Storm snow is bonding poorly with buried surface hoar, creating a very touchy storm slab problem.  A person may trigger large avalanches easily, or even from a distance. Wind slabs are also likely to be found behind ridges, ribs and gully walls.
Be aware of the potential for large, wide avalanches due to the presence of buried surface hoar.>Remote triggering is a concern, watch out for adjacent slopes.>Stay off recent wind loaded areas until the slope has had a chance to stabilize.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Jan 5th, 2013 2:00PM