Avalanche Forecast

Issued: Nov 18th, 2015 8:03AM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs, Loose Dry and Deep Persistent Slabs.

chris gooliaff, Parks Canada

Glacier.

80cm of new snow, strong winds, and warm temp's have created touchy slabs in the alpine and tree-line. Give the mountains some respect the next couple of days. Let the snowpack adjust to the new load.

Summary

Weather Forecast

A northwesterly flow has brought cooler, drier conditions to the region. Freezing levels will remain at valley bottom for the next few days, with moderate to strong W/NW winds at ridge-top, and generally sunny skies.

Snowpack Summary

80+cm of storm snow, accompanied by strong S-SW winds, have heavily loaded lee features and aspects, forming deep slabs. New snow overlies a crust below 1700m. The November 11 surface hoar layer is present above 1800m with localized distribution. An isolated basal weakness is capable of large slides.

Avalanche Summary

An extensive natural avalanche cycle occurred during yesterday's storm. Numerous size 2-3 avalanches were observed from all aspects, several running full path to valley bottom.

Confidence

Due to the number of field observations

Problems

Storm Slabs

The storm snow fell under strong SW winds creating heavy loading in lee features. Storm slabs will be touchy today and need time to bond to the underlying snowpack. If these slabs start to move, they have the potential to run to the valley floor.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.If triggered the storm/wind slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 3

Loose Dry

There is plenty of new snow to sluff from steep terrain. These avalanches can be particularity hazardous around terrain traps, especially with early season hazards like rocks and trees.

Sluffs may trigger deeper instabilities.Be cautious of sluffing in steep terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Deep Persistent Slabs

Recent natural avalanches have been triggered on this layer. New storm snow and strong winds will be capable of releasing large avalanches on this layer. These avalanches can easily reach the end of run out zones.

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.If triggered the storm slabs may step down to deeper layers resulting in large avalanches.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Nov 19th, 2015 8:00AM