Avalanche Forecast

Issued: Dec 21st, 2012 4:00PM

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

A.L. Horton, Parks Canada

Jasper.

Natural loose snow avalanches were observed on very steep terrain in thin snow pack areas. Ice climbers should evaluate routes and approaches that may have similar conditions above them.

Summary

Weather Forecast

Cold cloudy conditions with light flurries and light to moderate NW winds can be expected as arctic air moves into the forecast area.

Snowpack Summary

Up to 10 cm of new snow in the Icefields area has buried recently formed wind slab on NE aspects, tree line and above. The mid snowpack remains supportive however it is quickly loosing strength in shallow snowpacks.

Avalanche Summary

Natural loose snow avalanches have been reported on steep slopes below tree line where the snowpack is thin.Â Loose snow avalanches to size 2 were the result of avalanche control work on the Parkway on December 21st.Â The control work was on thin steep below tree line slopes.

Confidence

Wind effect is extremely variable on Saturday

Problems

Wind Slabs

10 cm of new snow has buried the wind slabs that formed earlier this week from moderate to strong SW winds in the Icefields area.

The recent snow may now be hiding windslabs that were easily visible before the snow fell.Caution in lee and cross-loaded terrain near ridge crests.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Deep Persistent Slabs

The strong mid-pack above this weakness is slowly loosing its strength. This issue is more prevalent in shallow snow pack areas.

Carefully evaluate and use caution around thin snowpack areas.Be aware of thin areas that may propogate to deeper instabilites.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 3

Valid until: Dec 22nd, 2012 4:00PM