Avalanche Forecast

Issued: Feb 21st, 2017 3:29PM

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

matt.mueller, Alberta Parks

Kananaskis.

Recent avalanche activity has us doubting the snowpack in large terrain. Ski quality is good in sheltered areas at the moment.

Summary

Confidence

High -

Weather Forecast

Convective flurries will bring us a few cm's tomorrow. Amounts are expected to be around 5cm, but this could vary locally. The alpine high will be -12. Light winds are expected from the north.

Avalanche Summary

A sz1.5 was noted below steep cliffs in the alpine. It only involved the storm snow.

Snowpack Summary

At Burstall Pass the recent snow has settled to 20cm with total depths approaching 2m. In places this new snow is a very soft slab that has been reactive in the past 24 hours. Beneath the new snow, the mid pack is well settled and gets progressively harder as you move down in the snowpack. The deeper layers are a mix of weak facets and depth hoar. There were repeatable failures(CTH22, SC) in the facet layer, down 50-70cm. This failure was difficult to initiate, however we expect this layer is weaker and easier to trigger in thin areas.

Problems

Wind Slabs

Wind slabs exist on all aspects but tend to be thicker on easterly aspects. These may be up to 50cm thick in heavily loaded areas.

If triggered the wind slabs may step down to deeper layers resulting in large avalanches.Avoid lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Persistent Slabs

This hard slab is spotty in nature. Expect to see it start near treeline and carry on higher. If it does react, it will likely propagate for a long ways.

Minimize exposure to overhead avalanche terrain, large avalanches may reach run out zones.Be aware of the potential for wide propagations.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

Past avalanches have stepped down to this layer. Thin areas and transitional terrain remain a concern.

Avoid steep convexities or areas with a thin or variable snowpack.Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Feb 22nd, 2017 2:00PM