Avalanche Forecast

Issued: Dec 23rd, 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.

A large scale natural avalanche cycle is starting to taper off. However, the snowpack is primed for human triggering. Choose conservative terrain.

Summary

Confidence

High.

Weather Forecast

Monday will be a mix of sun and cloud with very light flurries in the morning. Temperatures in the Alpine should rise to -8°c with generally light winds. Not too much snow is expected for Christmas.

Avalanche Summary

No new avalanches observed today, but there is evidence of a large recent avalanche cycle up to size 3 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

Strong westerly winds have formed widespread wind slabs in the Alpine and at Treeline, with many slabs up to 120cm thick. The Dec 10th interface of surface hoar and/or facets is the most active layer at the moment, and has been the failure plane for numerous recent avalanches. Look for this layer down 50 to 100+cm in the snowpack. The basal layers remain weak, and although this is concerning there hasn't been as much avalanche activity stepping down to the base of the snowpack in recent days.

Problems

Persistent Slabs

Continued strong winds are creating more dense slabs, especially in the Alpine and open areas at Treeline. Human triggering is very likely.

Avoid areas with overhead hazard.Use conservative route selection, choose moderate angled and supported terrain with low consequence.Avoid freshly wind loaded features.

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.

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

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1.5 - 3

Valid until: Dec 24th, 2018 2:00PM