Avalanche Forecast

Issued: Dec 24th, 2012 8:16AM

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 - Due to limited field observations

Weather Forecast

Tuesday: Strong SE winds. Alpine temp -11. No precipitation.Wednesday: Light SE winds. Alpine temp -9. No precipitation.Thursday: Light SW winds. Alpine temp -8. Light snow.

Avalanche Summary

A size 2 glide slab released on an east aspect during the weekend. No other recent avalanches have been reported.

Snowpack Summary

Wind slabs and cornices have developed on a fairly widespread basis and may be found in locations lee to NE, E and SE winds. Spotty surface hoar was buried in the upper snowpack in sheltered treeline areas, although little is known about its reactivity. Professionals are still mindful of a facet/crust layer near the base of the snowpack. Although triggering it has become unlikely, it may be possible with a very heavy load (e.g. cornice fall) or from a thin-spot trigger point. Continuing cold temperatures will do little to increase the strength of the snowpack.

Problems

Wind Slabs

Watch for wind slabs behind ridges and terrain breaks. These could be triggered by the weight of a person or snowmobile.

Be cautious as you transition into wind affected terrain.>Travel on ridgetops to avoid wind slabs on slopes below.>Stay well to the windward side of corniced ridges.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Deep Persistent Slabs

A deeply buried facet/crust weakness exists on a widespread basis. This layer could be triggered by large loads such as a cornice collapse or from a thin-spot trigger point.

Be aware of thin areas that may propagate to deeper instabilites.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 25th, 2012 2:00PM