Avalanche Forecast

Issued: Feb 13th, 2012 8:46AM

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

Avalanche Canada ccampbell, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain on Tuesday

Weather Forecast

Expect to wake up Tuesday morning with 10-15cm of fresh snow in the hills, but flurry activity is expected to taper off throughout the day. A building ridge of high pressure is expected to spread dry conditions Wednesday through Thursday morning before a frontalsystem arrives late Thursday bringing light precipitation. Freezing levels should remain near 1000m and winds should be light and variable throughout the forecast period.

Avalanche Summary

Loose surface snow may be susceptible to sluffing on steep slopes, but not expected to be particularly destructive unless terrain traps are in the runout. Deep persistent slab avalanches remain possible with heavy triggers in shallow rocky snowpack areas on unsupported slopes.

Snowpack Summary

By Tuesday afternoon, up to 15cm of fresh snow could be sitting on the widespread robust surface hoar created during the dry spell at the beginning of the month. This interface will be one to watch as it receives more snow load and/or the slab settles. Below that approximately 20cm of near-surface facets can be found on shady slopes while a sun crust can be found on southerly aspects. A well settled and strong snowpack sits on weak basal facets and depth hoar, which seem to be fairly widespread throughout the region. This deep persistent weakness was recently activated by warm temperatures, but cooler temperatures have once again reduced the sensitivity to triggers. Highly unpredictable glide cracks are also opening up, primarily on slopes with smooth ground cover. These full-depth gaping 'crevasses' could release without warning or act as a significant terrain trap.

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Deep and destructive persistent slab avalanches are unlikely, but a large trigger may activate this weakness on a steep, rocky & unsupported area with a shallow snowpack.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Cornices

An icon showing Cornices
Cornices are large, unsupported and may be a trigger for a large avalanche on the slope below.

Aspects: North, North East, East.

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Feb 14th, 2012 3:00AM

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