Avalanche Forecast

Issued: Jan 12th, 2013 9:35AM

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.

ghelgeson, Avalanche Canada

Kootenay Boundary.

Summary

Confidence

Fair - Due to variable snowpack conditions

Weather Forecast

Sunday: Ridgetop winds light NW. Freezing level at valley bottom. No significant snowfall. 1500m temp: -10Monday: Mod/Strong W/NW winds at ridgetop. Freezing level at valley bottom. No significant snowfall.Tuesday: Freezing level rising to 2000m around lunch time.

Avalanche Summary

Several reports of both natural and human triggered loose snow avalanches from steep terrain to size 1.5. Isolated skier controlled wind slabs to size 1 at ridge top.

Snowpack Summary

10 cm of light density snow fell Thursday adding to the 60 cm of settled storm snow that rests on the January 4th interface which consists of small facets, surface hoar (up to 12mm) in sheltered treeline and below treeline areas and sun crust on steep south and west facing slopes. The bonds at this interface are improving. The layer is still alive and well in test pits but has not been reactive to human triggering in the last day or so. Wind slabs created by the previously raucous SW winds have grown old & tired. The midpack is well bonded and strong. The November 28 surface hoar is still being found in isolated, sheltered below treeline locations buried 120cm. The deep crust/facet combo from early November still exists but seams to have gone dormant for the time being.

Problems

Persistent Slabs

The 50 - 100 cm of storm snow has settled out nicely and the likelihood of triggering has greatly decreased. I suspect it's still possible to trigger an avalanche failing on the Jan. 4th interface in terrain that is steep rocky and/or convex.

Be aware of the potential for large avalanches due to the presence of buried surface hoar.>Be cautious with open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 4

Wind Slabs

Wind slabs created during and just after the last storm have grown old and tired. Watch for isolated small wind slabs near ridgetop.

Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 4

Valid until: Jan 13th, 2013 2:00PM