Avalanche Forecast

Issued: Jan 16th, 2013 8:11AM

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

sylvia forest, Parks Canada

Glacier.

Conditions are changing - strong winds and warm air aloft are creating new avalanche problems. Cornices and winds slabs could trigger deeper weak layers.

Summary

Weather Forecast

A ridge of high pressure will continue to maintain dry conditions. The inversion is expected to continue today, providing warm clearing skies at higher elevations, and cloud and cooler temperatures in the valleys. Winds will stay moderate to strong.

Snowpack Summary

Warm temperatures in the alpine (inversion) combined with moderate to strong SW winds are continuing to create hard and soft slabs, especially in the alpine. These slabs overlie the January 4 interface, down 40-60cm. Steep solar aspects are most reactive due to facets on a crust. Significant loading should also be expected on NE aspects.

Avalanche Summary

Most reported avalanches have occurred on S and W aspects in the alpine, and are associated with the January 4 sun crust. Pockets of wind slab have also been observed to fail in specific terrain, mostly on cross loaded features. Cornices are beginning to fail, causing avalanches to size 2.

Confidence

Problems

Persistent Slabs

The January 4 crust-facet interface (down 60 cm) remains a concern. It is most problematic on steep S and W aspects. The slab above this is becoming more cohesive, and skier triggering remains likely.

Carefully evaluate big terrain features by digging and testing on adjacent, safe slopes.Good day to make conservative terrain choices.

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Wind Slabs

Strong SW winds combined with very mild temperatures in the alpine (0 degrees over night at 2000m) are contributing to wind slab development. Lee and cross-winded features (NE aspects) will be most loaded, however all aspects are suspect.

Be aware of the potential for wide propagations due to the presence of hard windslabs.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Jan 17th, 2013 8:00AM