Avalanche Forecast

Issued: Jan 12th, 2013 9:29AM

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

South Rockies.

Summary

Confidence

Fair

Weather Forecast

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

Avalanche Summary

Avalanche activity was limited to loose sluffs in steep terrain Friday.

Snowpack Summary

Around 50 cm of storm snow fell in favored locations earlier this week. This snow rests on a myriad of old surfaces (January 4th interface) that include sun crust on steep south and west facing terrain, surface hoar in sheltered locations at treeline and below and facets everywhere else. The bond at this interface is gaining strength. Our field team spent Friday in the Harvey Pass area hunting for this interface. They were unable to produce any failures on the interface in their test pits Wind slabs created during and just after last weeks storm have grown old and tired. The midpack is well settled and strong with one or two (location specific) crusts deep in the snowpack. These crust/facets combos are largely dormant, with the only concern being triggering from a shallow snowpack area or with a heavy trigger.

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 steep rocky and/or convex terrain.

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 the 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