Avalanche Forecast

Issued: Dec 26th, 2014 8:22AM

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

swerner, Avalanche Canada

Purcells.

Conservative decision making and disciplined terrain use is the name of the game when these tricky avalanche conditions persist. Check out the new Forecaster Blog @ avalanche.ca.

Summary

Confidence

Fair - Due to the number of field observations

Weather Forecast

A weak system will slide down the coast and start to affect the Interior on Saturday bringing mostly light snowfall amounts up to 10 cm. Ridgetop winds will be light-moderate from the west, switching to a northerly flow by Sunday. Alpine temperatures will hover around -15 and drop to -20 later Sunday. Conditions will remain cold and dry through Tuesday.

Avalanche Summary

Natural avalanche activity has tapered off, however; on Thursday an explosive triggered size 2.5 slab avalanche initiated in the mid-December surface hoar and stepped down to the early November rain crust. Yikes! Definitely something to keep on your radar.

Snowpack Summary

Storm snow totals 30-70 cm above a very touchy surface hoar layer that was buried mid-December. Below 2100 m this storm slab sits on a thick, solid crust/ surface hoar combo and has been acting as the perfect sliding layer. This persistent slab remains touchy to the weight of a skier and rider, especially in wind effected areas. A hard rain crust with facets from early November is buried over 1 m down and has recently been reactive with larger loads (explosives and smaller avalanches) especially in the Northern part of the region where the snowpack is thinner.

Problems

Persistent Slabs

A very touchy surface hoar layer is buried by a 40-90 cm thick persistent slab. This layer is widespread, and is easily triggered by skiers and riders. Remote triggering with wide propagation is a concern.

Stick to simple terrain, small features with limited consequence and be aware of what is above you at all times.>Use conservative route selection, dig down and test weak layers before committing to anything. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

The early November rain crust is buried 1-1.5 m down. It is still possible to trigger an avalanche on this interface, especially from shallow snowpack areas and thin-rocky, unsupported terrain.

Be aware of thin areas that may propogate to deeper instabilites.>Conditions may be worse in the north of the region, so get to know your local snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Dec 27th, 2014 2:00PM