Avalanche Forecast

Issued: Mar 17th, 2017 3:24PM

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

matt.mueller, Alberta Parks

Kananaskis.

Avoid backcountry travel for the time being. Recent avalanches have gone further than expected. In some case, mature trees have been taken down. A great time for the groomed XC ski trails or resorts!

Summary

Confidence

High -

Weather Forecast

Tonight will see another storm arrive from the SW. This will be with us for a day and bring significant amounts of snow. The main pulse is expected tomorrow and will leave just over 30cm. With the snow, we'll also see strong to extreme winds. At 2500m we're expecting SW winds 55-65km/hr. The temperatures will also creep up to -1° at 2500m.

Avalanche Summary

Nothing new was seen today, however clear skies offered a view of the extent of the last cycle. Alpine & treeline elevations had numerous avalanches on all aspects. All of them involved the deep layers. In terms of size, 2.5 to 3.5 avalanches were common. Crowns were up to 1.5m deep with very wide propagations.

Snowpack Summary

No new snow has fallen in the region today. The winds however have been moderate to strong in the alpine and have helped to build the windslabs. The re-distribution has caused localized loading in lee areas. An already stressed snowpack is struggling to support the new load. The cooler temps and cloud cover today helped to minimize the sun's effect and keep the surface snow cool. The principle concern at all elevations and aspects is still the deep, basal weak layers. The windslabs are a problem in themselves, but the bigger issue is the slabs' ability to trigger the deeper layers. Cornices are another large trigger that will almost certainly initiate a deep avalanche.

Problems

Storm Slabs

Warm temps, wind and new snow are the perfect mix for storm slab development. Given the winds, expect these to reach well below ridgelines. Lower elevations will likely have "settlement" slabs as the warm snow quickly settles

Avoid freshly wind loaded features.If triggered the wind slabs may step down to deeper layers resulting in large avalanches.

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

Elevations: All elevations.

Likelihood

Very Likely

Expected Size

1 - 3

Wind Slabs

These still exist from previous storms and are buried under 20-40cm of newer snow. They will be especially hard to identify with the new snow.

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

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

Any avalanche initiated in the upper snowpack could step down to the weak basal layers resulting in a very large avalanche. New snow and wind will add a significant and rapid load to this layer. This is a scary layer with huge destructive power!

Avoid exposure to overhead avalanche terrain, large avalanches may reach the end of run out zones.Pay attention to overhead hazards like cornices which could easily trigger the deep persistent slab.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 4

Valid until: Mar 18th, 2017 2:00PM