Avalanche Forecast

Issued: Jan 18th, 2018 3:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

New snow and strong winds are initiating an avalanche cycle in the alpine. The current snowpack is complex so choose conservative terrain as the snowpack settles.

Summary

Confidence

Moderate - Intensity of incoming weather systems is uncertain on Friday

Weather Forecast

A few more cm's of snow is likely to fall overnight with continued moderate to strong winds out of the SW. On Friday we are expecting snowfalls to diminsh and winds to calm down. Freezing levels are foreast to drop back to 1500m with daytime highs around -11C.

Avalanche Summary

Winds and new snow was triggering a few slabs out of lee and cross-loaded features up to sz 2. We suspect there was more slabs out but conditions were obscured throughout the day and visibility was limited.

Snowpack Summary

10-20cm of new snow fell over the past 24hrs with moderate westerly winds at treeline and suspected higher winds in the alpine. This new snow is also now burying the previous windslabs that developed last week as well as a new layer of surface hoar that was being found up to treeline. Two additional layers in the upper snowpack are still producing concerns. The Jan 6th down 40cm (moderate results) and the Dec 15th down 60-80cm (producing hard results). Despite a lack of recent activity on these interfaces they are still in our mind and we are treating she;tered treeline areas cautiously. Watch for new windslabs and storm slabs building along N and E aspects at treeline and above.

Problems

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 freshly wind loaded features.Avoid steep lee and cross-loaded slopes

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

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

Likely

Expected Size

1 - 2

Persistent Slabs

The new 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 unsupported slopes.Dig down to find and test weak layers before committing to a line.Avoid open slopes and convex rolls at treeline where buried surface hoar may be preserved.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2.5

Valid until: Jan 19th, 2018 2:00PM