Avalanche Forecast

Issued: Jan 8th, 2013 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Weather forecasts are calling for 40cm of new snow and extreme winds over the next 36hrs. This new snow loading will overload the Jan 6 weak layer and likely produce a significant natural avalanche cycle. Conservative terrain choices are recommended.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain

Weather Forecast

Up to 40cm of new snow is expected Tuesday night and Wednesday. winds will switch to the SW and remain in the extreme range (hitting 100km/h). Temperatures near -8 for a high on Wednesday.

Avalanche Summary

Few naturally triggered loose dry slides up to size 1.5 occurred at treeline and above on steep terrain on all aspects. One naturally triggered slab failed on a steep slope of Mt Nestor at 2700m on a S asp.

Snowpack Summary

5cm of new snow with up to 25cm of recent storm snow. Persistent strong westerly winds are cresting storm slabs in lee terrain. These slabs are producing cracking and small slab releases with ski cutting at treeline elevations. The Jan 6 layer of surface hoar and facets is reactive to stability tests in the easy range where storm slab conditions exist above the weak layer.

Problems

Storm Slabs

25cm of recent storm snow with strong to extreme W and NW winds have created touchy storm slabs. Ski cutting produces cracking and small slab releases at treeline and this condition will get worse with the incoming storm.

Avoid all avalanche terrain during periods of heavy loading from new snow and wind.>Avoid freshly wind loaded features.>Avoid lee and cross-loaded terrain near ridge crests.>

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

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 5

Loose Dry

Steep terrain on all aspects are producing loose dry avalanches up to size 1.5. Occasionally these slides are also triggering small slabs. This is of particular concern in terrain traps. Ice climbers and skiers should be aware of overhead terrain.

Avoid areas with overhead hazard.>Pay attention to overhead hazards like cornices.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Very Likely

Expected Size

1 - 3

Deep Persistent Slabs

Recent test results show the Nov rain crust to be generally unreactive, but this could change with the addition of new snow load over the next several days. Carefully evaluate shallow snowpack areas.

Carefully evaluate and use caution around thin snowpack areas.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 6

Valid until: Jan 9th, 2013 2:00PM