Avalanche Forecast

Issued: Dec 8th, 2015 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Storm slabs are sensitive to human-triggering. Watch localized conditions - if overnight storm snow amounts are more than forecasted, danger levels could reach HIGH.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Wednesday will bring moderate snowfalls with accumulations near 20cm. Alpine temperatures should reach -2 celsius with freezing levels near 1900m. Wind speeds will decrease overnight, but then return to the strong/extreme range on Wednesday afternoon.

Avalanche Summary

Nothing new was observed but visibility was very limited.

Snowpack Summary

Up to 15cm of new snow has fallen in the past 24hrs together with strong/extreme SW winds. This brings total snow overlying the Dec 4th layer to 20 to 40cm, and much more in lee features at ridge-top. The Dec 4th layer has developed into a critical weak layer. It consists of surface hoar crystals (some as large as 40mm) in sheltered areas below 2100m, sun crust on solar aspects, and facets in most other areas. This layer was reactive in field tests in the "easy" range today and forecasters observed cracking around their skis, all of which indicate a high likelihood of human triggering. Due to persistently strong SW winds over the past 48hrs, storm slab development has occurred in Alpine and Treeline areas on lee and cross-loaded features. The current and forecasted weather will lead to continued slab formation.

Problems

Storm Slabs

Storm slab formation is on-going in the Alpine and at Treeline in lee and cross-loaded features. Field tests today indicate that the Dec 4th interface is very sensitive to human triggering.

Avoid avalanche terrain during periods of heavy loading from new snow and wind.>Be careful with wind loaded pockets while approaching and climbing ice routes.>Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.>

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

Elevations: Alpine, Treeline.

Likelihood

Likely - Very Likely

Expected Size

2 - 4

Loose Dry

Recent wind and snowfalls are causing sluffing in steep terrain at all elevations.

Avoid travelling on ledges and cliffs where sluffing may have severe consequences.>Be cautious of sluffing in steep terrain.>Avoid areas with overhead hazard.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Valid until: Dec 9th, 2015 2:00PM