Avalanche Forecast

Issued: Mar 14th, 2016 8:47AM

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

matt.mueller, Alberta Parks

Kananaskis.

A healthy dump of snow and a medium avalanche cycle recently, its imperative to give the new snow time to settle out. This is prime time for skier triggered slab avalanches with potential also for stepping down to deeper layers. Cornices are immense.

Summary

Confidence

Moderate - Due to the number and quality of field observations

Weather Forecast

Cloudy with sunny periods and some convective flurry activity for Tuesday. Alpine temperatures at -8.0 and winds will be westerly light to moderate at upper treeline and moderate northwesterly winds in the alpine. Freezing levels will be valley bottom.

Avalanche Summary

A notable avalanche just outside the ski area boundary at Sunshine Village Ski area. A skier triggered a size 2.5 which was initiated on a crust which was buried February 11th and then proceeded to step down to basal facets causing the slide to dig to the ground and take the entire depth of the snowpack along with it. He took a ride for about a 100 meters and luckily pulled out of it. Yesterday there was report of a size 2.5 -3.0 off of Mt. Robertson that went ran to valley bottom and likely could have took out the normal path that ski tourers would take if exiting down the Robertson glacier and out the valley for the French/Haig/Robertson traverse.

Snowpack Summary

Up on the Spray today, light convective flurries continued with intermittent windows of good visibility. The recent storm (30-35 cm) snow has had some wind affect in specific treeline and alpine features that are exposed to the winds. So expect to see this in cross wind affected and in the immediate lee of the wind. Anticipate a bit of reverse loading as the upper flow is from the northwest so keep a sharp eye out for recent wind slabs on south through easterly aspects in the alpine. Within the mid depths of the snowpack are crusts buried from early March and February that we have seen little activity on but remain fantastic bed surfaces for avalanches especially in the presence of wind slabs. In the alpine, I am probing constantly to make sure I'm not walking into shallow, rocky snowpack areas where the potential for triggering deeply buried facets from early January is still possible. The big thing to keep in mind over the next few day is there is great deal of storm snow available for the wind to have its way with it and build some nasty wind slabs that could spoil your day.

Problems

Wind Slabs

We have been spared the usual howling winds after a new dump of snow but nonetheless, windslabs up to 40-50 cm thick will be lurking with some of the wind effect we have had, especially in the alpine.

Avoid lee and cross-loaded terrain near ridge crests.>Avoid freshly wind loaded features.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 5

Deep Persistent Slabs

We may sound like a broken record but its critical you probe with your pole in the alpine making sure you can discern shallow and rocky snowpack areas where triggering the facets from January in a big alpine terrain feature is still very possible.

Be aware of thin areas that may propogate to deeper instabilites.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Cornices

With all of the new storm snow and winds in the alpine there is little doubt cornices have grown and are ripe to tear off and trigger slab avalanches beneath them. Keep an eye out for the overhead hazards this week.

Pay attention to overhead hazards like cornices.>Avoid steep slopes below cornices.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Valid until: Mar 15th, 2016 2:00PM