Avalanche Forecast

Issued: Dec 10th, 2012 8:42AM

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

Avalanche Canada slemieux, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

25-35 cm of snow is expected to fall on the Caribous until Tuesday accompanied by strong winds from the West. Later Tuesday and Wednesday, a ridge after the system should bring lighter winds and slightly cooler temperatures (-10 C). A weaker system is forecasted for Thursday leaving some light precipitation on the region and stronger winds. 

Avalanche Summary

A small natural slab avalanche has been reported on a West facing slope at 2200 m around Valemont yesterday. There are limited recent observations from this region.

Snowpack Summary

Strong winds from the South East and South West has created winds slabs on lee slopes yesterday. These winds slabs will continue to build with the forecasted moderate precipitation and strong winds from the West tonight and tomorrow. I suspect that they will be easy to trigger these windslabs with light loads in the alpine and at treeline. Sluffing (dry loose avalanches) is also a concern on steep slopes in wind sheltered areas. Average snow depths at treeline is between 160 and 220 cm. Elevations below 1500 m are still reported as below threshold. The deep persistent instabilities (surface hoar and early November crust) located in the middle and near the bottom of the snowpack are still a concern not so much because of their sensitivity but more because of the large size avalanches they would produce if they would be triggered. In general, snowpack information 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

An icon showing Wind Slabs
Expect to find buried and newly formed windslabs in exposed lee slopes and cross-loaded gullies well below ridge crests.
Avoid large lee slopes during periods of heavy loading from new snow and wind.>Avoid exposure to overhead avalanche terrain, as large avalanches may reach the runout zones.>

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 5

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Be extra careful in areas where ground roughness is not present to act as an anchorage. Smooth ground cover areas include alpine firn, grassy slopes and smooth rock (......)
Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 7

Valid until: Dec 11th, 2012 2:00PM

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