Avalanche Forecast

Issued: Dec 6th, 2011 9:10AM

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

Avalanche Canada ccampbell, Avalanche Canada

Summary

Confidence

Fair - Due to limited field observationsfor the entire period

Weather Forecast

Wednesday: A chance of morning flurries, then clearing throughout the day. Freezing levels around 1200m and light to moderate northerly winds. Thursday and Friday: Clear with freezing levels reaching 2000m and light winds.

Avalanche Summary

One very recent size 2 slab was observed on Sunday on a north facing slope close to Keith's Hut in the Duffey Lake area. It appeared to be skier-triggered from the weekend.

Snowpack Summary

Surface hoar continues to grow and is getting really big below treeline. Low density surface snow is faceting on shady low elevation slopes and getting pretty crusty on sun-exposed treeline slopes. Total treeline snowpack depth is 150-180cm but wind-exposed areas are highly variable with scoured areas and deep drifts. Recent observations from wind scoured alpine slope in the Duffey Lake area include inconsistent hard sudden compression test results down 70cm on buried surface hoar, and just off the ground in facets. On a more sheltered westerly aspect moderate to hard sudden shears were observed down 40-50cm and 70cm on rounding facets. A lightly buried thick rain crust extends into treeline elevations.

Problems

Wind Slabs

An icon showing Wind Slabs
Wind slabs may be lurking below ridge crests, behind terrain features, and in cross-loaded gullies.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Valid until: Dec 7th, 2011 8:00AM

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