Avalanche Forecast

Issued: Dec 6th, 2012 9:58AM

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

mbender, Avalanche Canada

Northwest Inland.

Summary

Confidence

Poor - Due to limited field observations for the entire period

Weather Forecast

Friday:Broken clouds with some sunny breaks, ridgetop winds west 15 km/hr, and alpine temperatures near -10. Saturday:Increasing clouds as a warm front approaches. Periods of snow will begin in the evening. Winds west and northwest 30-50km/h. Temperatures near -8 in the alpine. Sunday:Light to moderate amounts of precipitation. Winds southwest 40km/h. Temperatures in the alpine -3.

Avalanche Summary

Recent reports of several isolated loose dry sluffs from steep terrain features. For a bit more information in the Hankin Area, check out the Regional Forum Posts.

Snowpack Summary

Wind slab instabilities exist in the upper snowpack at treeline and in the alpine. Treeline snow depths range between 90-125 cm. Snow depths in the alpine are highly variable with deep wind drifts and scoured slopes in exposed areas. A buried layer of small surface hoar crystals exists at tree-line in isolated sheltered areas. This is most likely buried down 15-20 cm under recent storm snow. A weak layer of facets sitting on a crust exists near the base of the snowpack down 80-130 cm. Test results on this layer earlier this week produced hard, sudden results.

Problems

Wind Slabs

New windslabs have formed in the lee of terrain features.

Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Deep Persistent Slabs

Deeply buried facet/crust weaknesses are often prone to remote triggering and step down avalanches. Typical trigger points include thin rocky areas. They may be difficult to trigger, but deep persistent slab avalanches are often very large.

Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

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