Avalanche Forecast

Issued: Feb 8th, 2013 8:21AM

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

Avalanche Canada mpeter, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Monday

Weather Forecast

Saturday: Expect mostly cloudy skies, with a chance of isolated flurries. Winds should be light from the west with alpine temperatures reaching -2.Sunday: Expect a mix of sun a cloud. Again, occasional light flurries are possible; likely confined to the northern half of the region. Winds should remain light from the west-southwest with alpine temperatures reaching -2.Monday: Flurries are likely to build over the day, with continued light west-southwest winds and alpine temperatures around -4.

Avalanche Summary

Avalanche activity has slowed but natural and rider triggered events are still being reported. Natural releases up to 2.5, predominantly in windloaded alpine and treeline locations and small accidental events (no involvements) have occurred. Loose wet sluffs at low elevations persist.

Snowpack Summary

Recent weather has been relatively benign, with precipitation pulses giving incremental loading (5-10cm at a time). Relatively light winds have accompanied these snowfall pulses with some stronger outflow winds closer to the coast. At lower elevations (below 700m), the drizzly rain is saturating and eroding the snowpack.Previous strong southwest winds gave intense snow transport and cornice growth. Extensive windslabbing in lee zones and behind ridges in the alpine and treeline was the result. Some areas saw swirling winds resulting in some cross and reverse loading on southeasterly features. These significant windslabs are now lightly buried.In the upper snowpack, various melt-freeze crusts remain a concern. Depending on your location, you may encounter crusts as shallow as 40cm and as deep as 110cm. Recent compression tests show both resistent and sudden planar results and an extended column test showed a continued propensity for propagation if the layer was triggered. It is certainly worth keeping these layers on your radar in regards to distribution and reactivity in the areas that you are riding. The mid and lower snowpack is generally well settled..

Problems

Wind Slabs

An icon showing Wind Slabs
Another pulse of snowfall and strong West winds will prolong the windslab issue. Previous SW winds have built windslabs in lee features and behind ridgecrests. Classic outflow winds have also contributed to the slabbing issue.
Be wary of lee and cross-loaded terrain near ridge crests.>Assess start zones carefully and use safe travel techniques.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Persistent Slabs

An icon showing Persistent Slabs
Various crust layers in the upper snowpack (location specific) still shows sudden results and a propensity for propagation in snowpack tests. Local investigation to test distribution and reactivity is a good idea before committing to steep slopes.
Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Feb 9th, 2013 2:00PM

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