Avalanche Forecast

Issued: Dec 1st, 2012 3:00PM

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

jeremy.mackenzie, Alberta Parks

Kananaskis.

Up to 25cm of recent storm snow has fallen, with a further 15+cm still to come. Strong SW winds and warm temps are promoting storm slab development, particularly in the Alpine. Cautious route selection is advised.

Summary

Confidence

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

Weather Forecast

Cool Alpine temperatures with winds increasing to 100km/h from the W. Between 15 and 20cm of new snow is expected for the next 24hrs.

Avalanche Summary

Observations were very limited due to poor visibility, but two small to medium size slides were heard (but not seen) coming from a steep E aspect at 2700m.

Snowpack Summary

Up to 10cm of new snow overnight with storm snow totals up to 25cm over the past 48hrs. Storm slab formation is ongoing in the Alpine and selected locations at Treeline due to strong SW winds. Shears exist with the storm snow, failing in the easy range on compression tests. The Nov rain crust, now buried an average of 100cm at Treeline continues to produce hard shear results.

Problems

Storm Slabs

Storm slab formation is ongoing. Up to 25cm of recent snow has fallen and winds are strong from the SW. Stability tests today indicate that the storm slabs are getting easier to trigger, particularly in the Alpine.

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

Likely

Expected Size

1 - 5

Wind Slabs

Pockets of buried wind slab are present in lee and cross loaded features in the alpine and isolated areas at tree line. These weakness are harder to locate with the new snow.

Avoid steep, open slopes.>Avoid thin, rocky or sparsely-treed slopes.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Persistent Slabs

The Nov rain crust persists about 30cm off the ground throughout the forecast area and is reactive to stability tests in the hard range. Avalanches in the upper snowpack may step down to this weakness.

Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Be aware of thin areas that may propagate to deeper instabilites.>

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 5

Valid until: Dec 2nd, 2012 2:00PM