Avalanche Forecast

Issued: Apr 5th, 2013 9:14AM

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

Avalanche Canada Peter, Avalanche Canada

Summary

Confidence

Good

Weather Forecast

Synopsis: A weak frontal system is forecast to move through on Friday night and into Saturday. Conditions should begin to dry out and clear on Sunday and Monday as a ridge of high pressure forms.Saturday: Cloudy with light snow – 5-10 cm. The freezing level is around 1000 m. Winds are moderate from the south-southeast. Sunday: Sunny breaks. The freezing level rises to 1400m during the day and winds are light from the north. Monday: A mix of sun and cloud. The freezing level is steady around 1400-1500 m.

Avalanche Summary

There were no reports of new avalanches on Thursday. A few new wet loose or slab avalanches were reported at lower elevations on Wednesday. Many of these were releasing on the ground and most were from steep solar aspects. Glide cracks and cornices continue to fail with some regularity.

Snowpack Summary

5-10 cm of new snow sits on a variety of old snow surfaces including a melt-freeze crust, moist snow, sugary facets, and wind affected snow. Pockets of wind slab could develop in exposed lee terrain over the next several days. Between 50-75cm below the surface is layer of surface hoar buried on March 9th which is variably reactive. In some areas it is stubborn and requires a significant trigger. In other areas the layer is still well preserved showing sudden planar or sudden collapse test results, and remains a primary concern among some professional operators.The mid snowpack is generally well settled and strong. Having said that, basal facets may resurface as a concern with spring warming, particularly in the north of the region. Cornices are large and untrustworthy.

Problems

Wind Slabs

An icon showing Wind Slabs
New winds slabs may form in exposed lee terrain and cross-loaded features. Triggering may be possible in steep terrain.
Be cautious as you transition into wind affected terrain.>Highmark or enter your line well below ridge crests to avoid wind loaded pillows.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Persistent Slabs

An icon showing Persistent Slabs
Recent reports of remote triggering suggest the March 9th surface hoar layer is still touchy in some areas. Where it is still reactive, avalanches can be large and potentially destructive.
Be aware of the potential for large, deep avalanches due to the presence of buried surface hoar.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Cornices

An icon showing Cornices
Large developed cornices loom over slopes. A cornice fall has the potential to initiate large avalanches.
Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 6

Valid until: Apr 6th, 2013 2:00PM