Avalanche Forecast

Issued: Jan 17th, 2013 9:36AM

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

ghelgeson, Avalanche Canada

South Rockies.

Summary

Confidence

Good

Weather Forecast

Friday: Extreme W ridgetop winds at ridgetop. No precip. Potential above freezing temperatures in the alpine.Saturday: Strong NW winds at ridgetop. No precip. Potential above freezing temperatures in the alpine.Sunday: Moderate NW winds at ridgetop. No precip. Potential above freezing temperatures in the alpine.

Avalanche Summary

No new significant avalanche observations have been reported from the region.

Snowpack Summary

Intense recent winds have redistributed snow and created large cornices. The snow surface is now a mix of sastrugi, hard slab and soft slab in open areas. Below this around 60cm of settled 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. Reports indicate that this bond has strengthened over time and is now fairly tight. The overlying slab has also settled significantly. The bond at this interface seems to have strengthened somewhat with time. The overlying slab has also settled significantly.

Problems

Wind Slabs

Strong to extreme winds out of the W/NW have left hard slabs, soft slabs, sastrugi and potentially unstable cornices in their wake. Watch for wind slabs behind midslope features like ridges and ribs. Be alert for wind slabs in unusual locations.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 4

Persistent Slabs

While unlikely, slopes that didn't slide in the last avalanche cycle may still be of concern this weekend. Triggering is most likely in areas that go from thick to thin in steep unsupported terrain.

Conditions are greatly improved, but be mindful that deep instabilities are still present.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Unlikely - Possible

Expected Size

1 - 5

Valid until: Jan 18th, 2013 2:00PM