Avalanche Forecast

Issued: Apr 4th, 2013 9:41AM

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.

pmarshall, Avalanche Canada

Northwest Coastal.

Summary

Confidence

Fair

Weather Forecast

Synopsis: A series of frontal systems will move through the province over the next few days bringing cloud and light snow to the Northwest. Friday: Light snow – 5-10 cm. The freezing level is around 800-1000 m and winds are moderate from the south-southeast. Saturday: Light snow continues. The freezing level remains around 1000 m. Winds are moderate from the south. Sunday: A mix of sun and cloud with a chance of flurries. Temperatures are pretty steady with daytime freezing levels around 1000-1200 m.

Avalanche Summary

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

Light new snow will bury a variety or 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

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.>Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

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

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 5th, 2013 2:00PM