Avalanche Forecast

Issued: Feb 18th, 2017 3:00PM

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

mike.koppang, Alberta Parks

Kananaskis.

The snowpack is beginning to strengthen with the cooler temperatures but at treeline and above the weak facetted base is making us very conservative.

Summary

Confidence

Moderate - Freezing levels are uncertain on Sunday

Weather Forecast

Temperatures on Sunday will average around -8C in Alpine terrain.Â Winds will be light to moderate out of the SW and only a trace amount of new snow is expected.Â Freezing levels are forecast to be around 1600m

Avalanche Summary

No new natural avalanche activity was observed over the past 24hrs.

Snowpack Summary

5-15cm of recent snow is now overlying a widespread temperature crust at lower elevations (up to 2000m) and up to 2400m on more solar aspects. As you climb into the alpine this new snow has been blown into thin (20-30cm) thick storm slabs. Field tests on Friday and Saturday were showing these new wind slabs to be unreactive to ski cutting but we werent willing to expose ourselves to larger slopes due to the weak faceteted basal layers down 100-120cm. Warm temps are helping to settle out the snowpack and strengthen it but this process takes time. We still have very little confidence in the stability of any large terrain feature and are continuing to limit our exposure to overhead terrain. Good skiing was being found in sheltered areas at TL and below.

Problems

Wind Slabs

New wind slabs 20-30cm thick are building in alpine areas.

Avoid steep convexities or areas with a thin or variable snowpack.Avoid lee and cross-loaded terrain near ridge crests.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Alpine and treeline areas have a sun crust on steep solar aspects up to 2400m. The deeper layers were insulated from the warmth and remain the same as they were before. Inspect this interface for signs of weakness.

Watch for areas of hard wind slab in steep alpine features.Be aware of the potential for wide propagations due to the presence of hard windslabs.Use caution in lee areas. Recent wind loading have created wind slabs.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 3

Deep Persistent Slabs

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

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

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Feb 19th, 2017 2:00PM