Avalanche Forecast

Issued: Jan 29th, 2019 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Despite the MODERATE hazard rating, this is a bit of a tricky time due to the highly variable snowpack. Most likely trigger spots will be in thin snowpack areas, which could produce very large avalanches.

Summary

Confidence

High -

Weather Forecast

Wednesday will begin with a frosty -22 Celsius, warming to about -8 Celsius by afternoon. Skies will be mostly sunny and winds will be light from the West. Some weather models are predicting that light flurries will move in Wednesday afternoon and continue Thursday and Friday with accumulations near 15cm.

Avalanche Summary

No new avalanches observed or reported today.

Snowpack Summary

5 to 10cm of low density recent storm snow overlies a very dense mid-pack of between 50 and 70cm at Treeline. Under this mid-pack is between 50 and 70cm of very weak facets, including depth hoar. The strong mid-pack is bridging over the weak layer in much of the region, but forecasters and being very cautious in shallow snowpack areas due to the higher likelihood of finding a weak spot (buried rock, thin spot, buried tree/shrub) that could act as a trigger. While triggering this deep persistent slab has a relatively low probability, the consequences will be high. Any avalanche that steps down to the basal layers will be large and destructive.

Problems

Deep Persistent Slabs

Respecting shallow areas can't be overstated right now. If this layer fails, it will almost certainly be from a shallow area and the resulting avalanche will likely be very large. Bouldery areas and sparse trees are examples of trouble spots.

Be aware of the potential for full depth avalanches due to weak layers at the base of the snowpack.Carefully evaluate and use caution around thin snowpack areas.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1.5 - 3

Wind Slabs

Isolated pockets of thin wind slabs can be found in the Alpine. Watch for these in the typical lee and cross-loaded features, but be aware of the possibility of "reverse wind-loaded" features due to the persistent NW winds.

Be aware of thin areas that may propogate to deeper instabilites.Caution in lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Valid until: Jan 30th, 2019 2:00PM