Avalanche Forecast

Issued: Dec 24th, 2014 8:00AM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs and Deep Persistent Slabs.

percy woods, Parks Canada

Glacier.

Summary

Weather Forecast

The forecast calls for a cooling trend, an end to the precipitation and a drop in wind speed to light over the next 24hrs. The extended forecast calls for light precipitation on Boxing day.

Snowpack Summary

A surface slab continues to build on top of the well preserved and widespread Dec 17th surface hoar layer (10-20mm) down 40 to 65cm depending on wind loading. This SH layer sits on top of a rain crust up to 2100m on well settled snow above 2100m. The Dec 9th surface hoar layer is down 80cm in the area. The Nov 9th crust is 30cm up from the ground.

Avalanche Summary

Skier triggered, skier remote and natural avalanches continued through Dec 23. Remote triggering of the surface slab from distances greater than 50m were reported Dec 22. Most of the activity was occurring between 1700-2400m. Moderate to strong southerly winds will be continuing to transport storm snow and overload the Dec 17 surface hoar layer.

Confidence

Problems

Storm Slabs

A 50cm slab sits over the December 17th surface hoar layer that reacted to human triggering yesterday. Sensitivity varies depending on drainage and elevation but the layer was observed to be almost everywhere. This layer is a real threat to riders.

Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

2 - 3

Deep Persistent Slabs

The new snow load continues to slowly build and this could reawaken the Nov 9 layer at the bottom of the snowpack. Shallow avalanches running on the surface hoar can also trigger this layer. This will be even more of a concern in the coming days.

Avoid shallow snowpack areas where triggering is more likely.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

3 - 4

Valid until: Dec 25th, 2014 8:00AM