Avalanche Forecast

Issued: Dec 18th, 2012 8:00AM

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

jon schleiss, Parks Canada

Glacier.

Moderate to strong winds overnight have created soft windslabs near ridgelines in alpine and treeline elevations.

Summary

Weather Forecast

Cool and clear today with a short snow storm on Wednesday with up to 15cm of new snow, followed by dry cold air from the North on Thursday.

Snowpack Summary

At treeline and above, soft windslabs have formed due to 50k winds at ridgelines. Elsewhere, 40cm of loose storm snow overlies a well settled snowpack. The Nov28 surface hoar down 80cm and is found in some locations.� The early Nov crust is widespread and down 1.5m. Tests on these layers indicate they would be hard to trigger.

Avalanche Summary

Yesterday avalanches were observed up to size 3, and were dry slabs running to 1/2 fan. Expect more dry avalanche activity due to the moderate to strong southerly winds overnight.

Confidence

Problems

Wind Slabs

Strong winds overnight and lots of storm snow have created touchy windslabs above 2300m that are easily triggerable on convex, unsupported features. Look for soft slabs at treeline and above, near ridgelines.

Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 3

Persistent Slabs

While the thick crust at the base of the snowpack has yet to be reactive, if it does produce an avalanche it will be very large. Cornice falls or other avalanches stepping down to this layer, or triggering from thin areas are possible.

Sluffs may trigger deeper instabilities.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 19th, 2012 8:00AM