Avalanche Forecast

Issued: Dec 7th, 2012 9:38AM

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

Saturday: The effects of a weak ridge of high pressure will be brief. Generally broken skies with little to no precipitation for most of the day with a warm front pushing in for the late afternoon. Light amounts of snow are expected for the overnight period into Sunday.Â Winds northwest 20 km/h for the daytime period changing to west 30-50km/h in the late afternoon. Alpine temperatures -8. Sunday: Light to moderate precipitation throughout the day with strong northwesterly winds. Alpine temperatures -4 degrees. Monday: Continued light to moderate precipitation with southwesterly winds 30km/h. Freezing levels expected at 800m with alpine temperatures -6 degrees.

Avalanche Summary

There is no new avalanche activity to report at this time.Â If you have been traveling in the backcountry recently, send us your observations. Every bit of information helps us to produce a better product. Email us at forecaster@avalanche.ca

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 heavily scoured slopes in exposed areas. A 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.

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 - 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.

Carefully evaluate and use caution around thin snowpack areas.>Be aware of thin areas that may propagate to deeper instabilites.>Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

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