Avalanche Forecast

Issued: Feb 17th, 2015 3:00PM

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

Alberta Parks matt.mueller, Alberta Parks

Conditions have improved within the snowpack. Local variability is an issue worth some exploration. During your travels, take some time to assess the layers and look for local instabilities. Good skiing today on sheltered north aspects.

Summary

Confidence

Good

Weather Forecast

We are expecting the large temperature differential to continue for the next few days. Freezing levels will rise to 1600m tomorrow with some intermittent sun expected. Winds will remain westerly and average 35km/hr at 2500m. Valley bottom winds will remain light. 2500m temps will be around -5 as a high. No snow is expected.

Avalanche Summary

Some small, loose dry avalanches from yesterday were noted today. No slab avalanches were seen.

Snowpack Summary

In the past 48hrs we've had spotty convective flurries that have left 3-12cm's of new snow. This new snow is very low density and easily blown around by the wind. We have yet to see any significant storm slab development. Below the new snow we have a rare February crust that formed during the last warm spell. This thin breakable crust is widespread up to 2050m, and on solar aspects it stretches up to the 2200m mark. So far it is insignificant as its only down 10cm's on average. Profiles today at treeline showed a much more settled and stronger snowpack that what we've seen lately. It seems the northern region of the forecast area has a stronger snowpack in general. The snow depth at the profile was 153cm, elevation was 2100m, and on a north aspect. Tests gave inconclusive results. One test had a moderate result and another 50m away had a hard result. In both cases the failure type was not very concerning. Of note was the moist layer on the ground. The depth hoar layer was 10cm thick and fairly well bonded for depth hoar. In the alpine, the winds were gusting to about 30km/hr. Expect the alpine snowpack to consist of laminated windslabs and a weak depth hoar bottom.

Problems

Wind Slabs

An icon showing Wind Slabs
The various buried windslabs have bonded together in the last while. Steep, convex terrain at upper treeline and alpine elevations are a likely spot to find trouble with this layer.
Choose well supported terrain without convexities.>Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

2 - 4

Deep Persistent Slabs

An icon showing Deep Persistent Slabs
As the upper layers gain strength through the cooling process, we can expect this layer to settle down and become less active. Having said that, remember that thin spots can be problematic. Large triggers are still a concern.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

3 - 6

Valid until: Feb 18th, 2015 2:00PM