Avalanche Forecast

Issued: Jan 19th, 2018 3:00PM

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 Persistent Slabs.

Alberta Parks mike.koppang, Alberta Parks

Strong winds have punished the snowpack in most open areas.  Watch for pockets of preserved surface hoar at treeline and below! 

Summary

Confidence

High -

Weather Forecast

A trace of new snow may fall overnight with temperatures on Saturday around -11C in the Alpine.  Winds will continue to be moderate out of the SW.

Avalanche Summary

A few new size two avalanches were observed in the past 24hrs.  These avalanches were seen in steeper treeline areas failing down 30-40cm.  Explosives results produced a few smaller avalanches and one larger treeline avalanche that crossed the smith dorrien highway.

Snowpack Summary

20cm of recent snow over the past 48hrs with strong winds.  Alpine terrain has definetly been ravenged by the winds with some windward slopes stripped bare and hard slabs on more N and E aspects.  At treeline there are two surface hoar layers down 30cm (Jan 6th) and down 50cm (Dec 15th) that have slowly becoming more reactive over the past few days.  Steeper features and unsupported roles should be treated with caution, especially in un-skied terrain.    No recent activity on the November crusts but we have not let these weaknesses fall from our thoughts.  Weak facets can be found surrounding these layers which indicates that these is potential for a slide to step down to one of these layers.

Problems

Wind Slabs

An icon showing Wind Slabs
Strong winds and warm temps have combined to build widespread windslabs in the alpine & open treeline areas. These slabs are overlying a melt freeze crust on solar aspects and surface hoar at treeline and below.
Avoid steep lee and cross-loaded slopesAvoid freshly wind loaded features.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Persistent Slabs

An icon showing Persistent Slabs
Up to treeline being found especially in sheltered areas.
Avoid convex rolls at and below treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

An icon showing Persistent Slabs
The recent load may begin to make the December 15th interface more reactive. This layer has turned into a 5-10cm thick facet layer and isolated surface hoar at treeline elevations.
Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.Dig down to find and test weak layers before committing to a line.Avoid unsupported slopes.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Jan 20th, 2018 2:00PM

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