Avalanche Forecast

Issued: Jan 10th, 2013 9:52AM

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

pgoddard, Avalanche Canada

South Columbia.

Check out the Forecaster's Blog for thoughts about the coming weekend.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Friday: Light NW wind. Alpine temperature near -15. No snow.Saturday: Light W wind. Alpine temperature near -12. No snow.Sunday: Light NW wind. Alpine temperature near -14. No snow.

Avalanche Summary

A natural cycle of size 1-3 storm slabs occurred over the last three days. Skiers also several avalanches up to size 2, failing on buried surface hoar or facets.

Snowpack Summary

50-90 cm of recent snow has developed into slabs above old snow surfaces including surface hoar (found especially at and below treeline in sheltered areas), a sun crust (on steep S to SW-facing slopes) and facets. The distribution of buried surface hoar is patchy, but in the neighbouring North Columbia region, it is extremely touchy in some areas, with widespread propagation and remote-triggering occurring. I donâ€™t yet have enough information to know how isolated this problem is, so youâ€™ll need to get your shovel out and test this layer in your local area.Strong winds have left wind slabs in the lee of terrain breaks such as ridges and ribs at alpine and treeline elevations. In areas sheltered from the wind, fast-moving sluff could throw you off your feet or carry you into a terrain trap. A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is now considered inactive.

Problems

Persistent Slabs

Storm snow is particularly reactive where it overlies buried surface hoar. This weakness may be triggered from a distance and avalanches could be surprisingly large.

Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>Remote triggering is a concern, watch out for adjacent slopes.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 6

Wind Slabs

Wind slabs have formed behind terrain breaks such as ridges and ribs. 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.>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 - 5

Valid until: Jan 11th, 2013 2:00PM