Avalanche Forecast

Issued: Nov 30th, 2012 9:13AM

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

Avalanche Canada jlammers, Avalanche Canada

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Saturday: Moderate to heavy snowfall / Moderate southwest winds with strong gusts / Freezing level at 1500mSunday: Light snowfall / Light southeasterly winds / Freezing level @ 1300m Monday: Light to moderate snowfall / Moderate to strong southwesterly winds / Freezing level @ 1200m

Avalanche Summary

On Friday there were reports of natural and skier triggered slab avalanches to size 1.5 in the Kootenay Pass area. They occurred on north aspects and are suspected to have run on the November 28th surface hoar.

Snowpack Summary

Recent snowfall accumulations across the region have been highly variable; however, as of Friday some areas had upwards of 30cm overlying a variety of surfaces which may include weak surface hoar crystals, a sun crust on steep solar aspects, and well settled storm snow from last week. Forecast wind and snow will add to the size and reactivity of this developing slabIn the mid snowpack there may be a spotty, thin buried surface hoar layer between 50 and 80cm down. At the base of the snowpack sits the early November rain crust. Located about 100cm below the surface, it seems most likely to be found in deeper snowpack areas and may have associated facets. These layers seem to have been unreactive in recent days, but may have the potential to 'wake-up' with forecast loading.In general, snowpack data is sparse in this region and significant variations likely exist from one drainage to another. In short, digging down and making your own observations will be critical to safe slope selection. Any observations from the field are welcome at forecaster@avalanche.ca.

Problems

Storm Slabs

An icon showing Storm Slabs
Wind and snow forecast for Friday night and Saturday will add to the size and reactivity of this storm/ windslab. This developing avalanche problem may override a variety of potentially weak surfaces such as sun crusts and surface hoar.
Avoid all avalanche terrain during periods of heavy loading from new snow and wind.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
Although the likelihood of a release is low, the consequences of a persistent slab release could be significant. These layers may wake-up with additional loading.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 1st, 2012 2:00PM