Avalanche Forecast

Issued: Dec 4th, 2012 4:00PM

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

tim haggarty, Parks Canada

Waterton Lakes.

There is skiing above 1900m! But, all the ice climbs have fallen off too! Access to higher elevations requires the use of summer trails still, and watch for early season hazards (rocks, stumps) that are hidden just below the surface.

Summary

Weather Forecast

Continued mild temperatures are expected with some potential for modest accumulations of snow above 1700m. Drying expected Wed and Thurs. Likely to experience continued moderate W and SW winds throughout the period.

Snowpack Summary

Little to no snow below 1500m. At 1800m there is approx 60 cm which does not allow travel off of summer trails. A rain crust buried Nov 30 persists to 1950m. At 2000m we have found over 150cm in sheltered areas with crusts found only at the bottom.

Avalanche Summary

Avalanche activity has centered around extreme terrain in the immediate lee areas fromÂ recent winds. Visibility has been poor in the last 48-hours with fog and precipitation.

Confidence

Intensity of incoming weather systems is uncertain

Problems

Wind Slabs

Slabs developing in open lee areas with W and SW winds. Below 1950m these will be sitting on a crust. Above 1950m there is a chance that surface hoar exists in protected areas. There is a large amount of snow now available for transport.

Be alert to conditions that change with elevation.Caution in lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Deep Persistent Slabs

Buried crust layers exist at all elevations. At 2000m these are limited to basal layers which are starting to show signs of growing weak crystals. Thin areas will be of concern where cool temperatures can penetrate and triggering is more likely.

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

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 3

Valid until: Dec 5th, 2012 4:00PM