Avalanche Forecast

Issued: Feb 7th, 2015 7:28AM

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

Alberta Parks mike.koppang, Alberta Parks

A natural avalanche cycle is still ongoing in Alpine areas.  Cornices are large and failing in the warm temperatures triggering avalanches up to sz 3 on underlying slopes. 

Summary

Confidence

Good

Weather Forecast

Temperatures are going to cool slightly over the next few days with freezing levels forecast to drop to 1700m.  There may be a few isolated flurries but little accumulation is expected.  Winds will continue to be moderate at higher elevations out of the SW.

Avalanche Summary

Numerous natural avalanches were observed throughout the day on Saturday.  Many of these slides were sz 1.5-2 and failing within the storm snow but there were also a few larger slides, likely triggerred by Cornice failures that were failing down deeper in the snowpack producing size 3 avalanches.  Most of these slides initiated in Alpine terrain and ran to the middle of their normal runouts.

Snowpack Summary

Up to 50cm of recent snow is overlying the 0131crust which continues to produce moderate to easy sheers on a layer of facets overlying the crust..  The 0131crust is being found up to 2900m on steep solar aspects and only up to 2200m on more polar aspects.  Warm temps, combined with the recent new snow and winds are building new windslabs and storm slabs that are skier triggerrable.  Some recent slide activity has shown evidence of stepping down to deeper layers such as the Dec 13th crust as well as the November rain crust way down in the snowpack.

Problems

Storm Slabs

An icon showing Storm Slabs
Cracking and whumpfing was being observed on Saturday in open wind affected areas. 
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid freshly wind loaded features.>Avoid lee and cross-loaded terrain near ridge crests.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 4

Wind Slabs

An icon showing Wind Slabs
New windslabs are building in Alpine terrain and open areas at treeline.
Avoid unsupported slopes.>Carefully evaluate and use caution around thin snowpack areas.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
A few avalanches recently stepped down to this interface (the November rain crust) causing larger avalanches.
Be aware of the potential for large, deep avalanches.>Be aware of thin areas that may propogate to deeper instabilites.>Avoid steep slopes below cornices.>Extra caution needed around cornices with current conditions.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

3 - 6

Valid until: Feb 8th, 2015 2:00PM