Avalanche Forecast

Issued: Jan 21st, 2013 8:07AM

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.

pgoddard, Avalanche Canada

Northwest Inland.

Summary

Confidence

Fair - Timing, track, or intensity of incoming weather is uncertain for the entire period

Weather Forecast

Two frontal systems are due to affect the area, but the timing of these is uncertain.Tuesday: Moderate S wind.Â Alpine temperature near -1. Light snow.Wednesday: Light to moderate SW wind.Â Alpine temperature near -6.Moderate snow.Thursday: Increasing S winds. Alpine temperature near -5. Moderate snow, probably starting late in the day.

Avalanche Summary

On Friday, hard wind slabs failed naturally in the north of the region on northeast and east aspects. In isolated occurrences, these triggered full-depth avalanches that ran on basal facets. No avalanches have been reported since then.

Snowpack Summary

The current medley of snow surfaces includes hard and soft wind slabs, scoured slopes, blue ice and thin melt-freeze crusts. Surface hoar layers buried in the upper snowpack are patchy in their distribution. Recent snowpack tests gave moderate to hard, resistant results on one of these layers near Smithers. An otherwise strong mid-pack overlies a weak base layer of facets/depth hoar and the remnants of a crust. The snowpack depth is around 100 cm at treeline.

Problems

Wind Slabs

Hard and soft wind slabs may be found on many slopes, even at treeline. Although they are gaining strength, it may be possible to trigger a wind slab with the weight of a person or snowmobile.

Be aware of the potential for wide propagations due to the presence of hard windslabs.>Travel on ridgetops to avoid wind slabs on slopes below.>Give cornices a wide berth when travelling on or below ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Deep Persistent Slabs

A deeply buried facet/crust weakness exists near the base of the snowpack. This layer could be triggered by large loads such as a cornice collapse or from a thin-spot trigger point.

Avoid convexities or areas with a thin or variable snowpack.>Choose the deepest and strongest snowpack areas on your run.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 6

Valid until: Jan 22nd, 2013 2:00PM