Avalanche Forecast

Issued: Dec 24th, 2018 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Whumpfing and cracking continue to occur. Avoid big slopes or terrain with high consequences. Watch those steep roof lines Santa!

Summary

Confidence

High -

Weather Forecast

Christmas Day will bring a mix of sun and cloud, light SW winds, temperatures between -15 and -20 and no new snow. For Boxing Day expect much of the same but about 5 to 10 degrees warmer.

Avalanche Summary

A couple of new naturally triggered slab avalanches were observed today in steep Alpine terrain. Overall the natural activity has tapered, but there has been recent activity up to size 3.0 primarily on East and North aspects over the past few days. Wide propagations have been observed and some slides have reached the valley bottoms.

Snowpack Summary

Wind slabs are widespread in the Alpine and at Treeline, with slabs up to 120cm thick. The Dec 10th surface hoar/facet interface remains active, with easy to moderate shears down 40 to 60cm. The basal layers are very weak and facetted, with occasional ski penetration to ground when you leave the up-track. Forecasters experienced a very large settlement today which indicates the snowpack remains prime for human-triggering.

Problems

Persistent Slabs

Slabs are everywhere in lee and cross-loaded terrain in the Alpine and open areas at Treeline. The Dec 10th interface is either surface hoar or facets, and both are producing shears. Human triggering is very likely in wind loaded features.

Avoid freshly wind loaded features.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Remote triggering is a concern, watch out for adjacent slopes.

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

Elevations: All elevations.

Likelihood

Likely

Expected Size

1.5 - 3

Deep Persistent Slabs

Some of the recent larger avalanches may have stepped down to this layer.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Be cautious in shallow snowpack areas where triggering is more likely.Carefully evaluate terrain features by digging and testing on adjacent, safe slopes.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Dec 25th, 2018 2:00PM