Avalanche Forecast

Issued: Jan 12th, 2013 8:55AM

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

pgoddard, Avalanche Canada

South Columbia.

Summary

Confidence

Fair - Freezing levels are uncertain for the entire period

Weather Forecast

Sunday: Light N wind. Alpine temperature near -12. No snow.Monday: Moderate NW wind. Alpine temperature near -5. Light snow.Tuesday: Moderate NW wind. Alpine temperature near -3. No snow.

Avalanche Summary

A natural and human-triggered cycle of size 1-3 storm slabs occurred last week. Many were failing on buried surface hoar or facets. Natural activity has decreased, but human-triggering remains a concern.

Snowpack Summary

50-90 cm of recent snow is settling over 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 where it exists, it may still be touchy. Many operators are cautiously optimistic that it is showing an improved bond. Recent 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

Recent storm slabs are slowly settling, but they may still be touchy in areas where surface hoar is buried. 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.>Be wary of slopes that did not previously avalanche - even on low angle terrain.>Dig down to find and test weak layers before committing to a line.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 5

Wind Slabs

Wind slabs may be found 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.>Use ridges or ribs to avoid pockets of wind loaded snow.>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 13th, 2013 2:00PM