Avalanche Forecast

Issued: Jan 18th, 2013 8:21AM

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

pgoddard, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Saturday: Moderate W winds. Alpine temperature near -2. No snow.Sunday: Light to moderate W winds. Alpine temperature near -2. No snow.Monday: Light SW winds. Alpine temperature near -2. No snow.

Avalanche Summary

A couple of large glide slab releases have been observed. Otherwise, no new avalanches have been reported.

Snowpack Summary

Strong NW through SW winds have left wind slabs in many areas, even at treeline. These are likely to be gaining strength as time goes on and the amount of snow available for transport diminishes. Around 40-60 cm settled storm snow sits above 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 these weaknesses is patchy, but where they exist, it may still be possible to trigger a large avalanche with the weight of a person or snowmobile. Test results on these interfaces vary from no result to moderate, sudden results. A strong mid-pack overlies a weak facet/crust layer near the base of the snowpack, which is generally considered inactive.

Problems

Wind Slabs

Wind slabs may be found behind terrain breaks such as ridges and ribs. It may be possible for a wind slab to step down to a deeper instability.

Be aware of the potential for wide propagations due to the presence of hard windslabs.>Use ridges or ribs to avoid pockets of wind loaded snow.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Persistent Slabs

Triggering persistent slabs is becoming less likely, but a cautious approach to steep south-facing slopes and sheltered terrain below treeline is still advised.

Dig down to find and test weak layers before committing to a line.>Be aware of thin areas that may propagate to deeper instabilites.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Valid until: Jan 19th, 2013 2:00PM