Avalanche Forecast

Issued: Dec 6th, 2012 9:59AM

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

mbender, Avalanche Canada

Cariboos.

Summary

Confidence

Poor - Due to limited field observations for the entire period

Weather Forecast

Friday: The effects of a ridge of high pressure building over the pacific will result in generally broken skies with the chance of locally light precipitation. Winds light from the northwest. Alpine temperatures -9.Saturday: Generally sunny skies and cooler temperatures. Light northwesterly winds and temperatures near -13 in the alpine.Sunday: Increasing clouds as a warm front approaches from the northwest.

Avalanche Summary

There are limited recent observations from this Region. Recent reports indicate a few natural avalanches to size 2.5 in the past 48 hours running in the recent storm snow 60-80cm deep on a north aspect at 2200m.

Snowpack Summary

40-60 cm of storm snow has fallen over the past 5 days. Instabilities (surface hoar layer, and a thin sun crust) may exist within or down 40-60 cm. We have very limited information on the extent or sensitivity of these layers, but suspect them to be reactive under the load of the new snow. A second buried surface hoar layer, down about 115 cm, and the early November rain crust (facet-crust combo), over 140cm down in some locations, remain a concern for isolated deep slab avalanches.Average snow depths at treeline seem to be between 140cm and 180cm. Elevations below 1500m are still reported as below threshold.In general, snowpack data is sparse in this region and significant variations likely exist from one drainage to another. 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

Wind Slabs

Deep and dense wind slabs are likely in exposed lee slopes and cross-loaded gullies well below ridge crests.

Be cautious as you transition into wind affected terrain.>Use ridges or ribs to avoid pockets of wind loaded snow.>

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 5

Deep Persistent Slabs

Although the likelihood of a release is low, the consequences of a persistent slab release are high. These layers may wake-up with additional loading.

Be aware of thin areas that may propagate to deeper instabilites.>Whumpfing is direct evidence of a buried instability.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Dec 7th, 2012 2:00PM