Avalanche Forecast

Issued: Dec 4th, 2012 8:25AM

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

jon schleiss, Parks Canada

Glacier.

High winds and lots of new snow over the last few days, combined with forecast strong winds for today, have contributed to avalanche conditions. Expect natural avalanches today.

Summary

Weather Forecast

Moderate snowfall and strong winds are in the weather forcast for this area today and tonight and then both the wind and snowfall should ease to light wind and flurries for Wednesday.

Snowpack Summary

A 70cm storm slab from a layer buried Nov. 28 is becoming increasingly cohesive due to moderate to strong winds. The Nov 6 crust may become reactive with increasing load.

Avalanche Summary

Yesterday an avalanche cycle occurred during a period of intense wind and snowfall. 6 size 3, and 13 size 2-2.5 natural avalanches were observed from steep paths adjacent to the highway, east of the Summit.

Confidence

Timing, track, or intensity of incoming weather system is uncertain on Thursday

Problems

Wind Slabs

Moderate to strong S-SW winds have loaded lee slopes, triggering natural avalanches in steep terrain. Expect touchy loaded pockets, and soft windslabs on lee slopes. Strong forcast winds will enhance this problem.

Avoid freshly wind loaded features.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Storm Slabs

We've received 70cm of snow in the past 4 days. This soft slab will be most reactive where it buried surface hoar or sun-crust. We expect more snow and strong winds today, which may overload these layers resulting in natural avalanches.

Avoid areas with overhead hazard.Make observations and assess conditions continually as you travel.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

The Nov 6 crust complex has yet to wake up. While the likelihood of triggering is low, it will produce large avalanches. As the load on this layer increases, it may become reactive. Smaller avalanches may step down to this deeper layer.

Avoid avalanche terrain during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 5th, 2012 8:00AM