Avalanche Forecast

Issued: Dec 7th, 2012 9:36AM

The alpine rating is considerable, the treeline rating is moderate, 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

Saturday: The effects of a weak ridge of high pressure will be brief. Generally sunny skies for most of the day. No precipitation expected with light northwesterly winds. Alpine temperatures -12 degrees.Sunday: Generally overcast with light amounts of precipitation accompanied by winds from the northwest at 20-30km/h.Alpine temperatures -8 degrees.Monday: A warm front is expected to give a rise in freezing levels to 900m. Light to moderate precipitation along with moderate to strong westerly winds. Alpine temperatures -9.

Avalanche Summary

There are limited recent observations from this region.

Snowpack Summary

Up to 70 cm of new snow has fallen in the past 5 days. Instabilities (surface hoar layer, and a thin sun crust) may exist within or down 50-70 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 150cm and 190cm. 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

Expect to find buried and newly formed windslabs 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, South.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Deep Persistent Slabs

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

Avoid convexities or areas with a thin or variable snowpack.>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

2 - 6

Valid until: Dec 8th, 2012 2:00PM