Avalanche Forecast

Issued: Jan 27th, 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.

Alberta Parks matt.mueller, Alberta Parks

Snowpack depth seems to be a key piece to the avalanche puzzle. Watch for shallow areas as you approach upper treeline and alpine areas.

Summary

Confidence

Moderate - Wind effect is extremely variable

Weather Forecast

Temps will fall overnight to the -15 to -20. No snow is forecast, but as I say that I look out the window and see it snowing...flurries might give a few centimeters of new snow. The winds will continue to be from the NW, but they will slow down to the moderate range.

Avalanche Summary

We had reports of an avalanche on Snowpeak yesterday, but details are few right now. All we know for sure was it was in a shallow, alpine snowpack. There was also a fresh but distant avalanche noted today in the high alpine towards Mt Assiniboine. Likely a cornice trigger maybe a 2.5, east aspect.

Snowpack Summary

Quite a few changes last night. Firstly, the wind once again picked up and created new slabs in the alpine. Judging from how things look, these slabs are isolated in nature and mostly in immediate lee areas. Treeline was spared the full brunt of the wind so there is a bit of new snow overlying the older windslabs. Having said that, there may be slabs in wind exposed areas. Secondly, there is a hint of sun crust on solar aspects. In Alpine and treeline areas the mid pack is generally well settled with a minor shear (failure) noted on the Jan 17 layer. I say minor because the snow above isn't a slab yet and the layer is shallow. The deeper weak layers are just...deep & weak. From what we can gather, in deeper snowpack areas the bridging effect of the midpack keeps the house of cards from collapsing. In shallow areas, all bets are off. That layer is delicate and if it fails, expect a large avalanche!

Problems

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
Respecting shallow areas can't be overstated right now. If this layer fails, it will almost certainly be from a shallow areas. 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

2 - 3

Wind Slabs

An icon showing Wind Slabs
There are new slabs from the wind as well as buried slabs. In both cases, expect to find the in immediate lee areas.
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.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 2.5

Valid until: Jan 28th, 2019 2:00PM