Avalanche Forecast

Issued: Jan 6th, 2013 9:35AM

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

Avalanche Canada jfloyer, Avalanche Canada

Summary

Confidence

Fair - Intensity of incoming weather is uncertain

Weather Forecast

Monday: 10-15 cm new snow is expected with southeasterly ridgetop winds gusting to 50 km/h. Treeline temperatures around -3C. Tuesday: Dry during the day with snow starting up late in the day. Moderate westerly ridgetop winds. Treeline temperatures around -6C. Wednesday: 10-20 cm new snow with strong southwesterly winds. Models do not currently agree on the amount of snow with this system.

Avalanche Summary

At this point, only sluffing in the recent storm snow has been observed. I suspect storm and wind slabs will start to develop with continued new snow and wind through the storm.

Snowpack Summary

The new snow is bonding poorly to existing snow surfaces that include surface hoar (up to 20 mm in size), facets, hard wind slabs or a sun crust. The upper storm slab has so far been reported as thin (10-20 cm) and soft. However, with more snow it will rapidly increase in thickness and danger. Recent SE winds have formed new wind slabs at alpine and treeline elevations. No significant shears have been observed recently below the recent storm snow in the mid snowpack layers. Near the base of the snowpack, a crust/facet layer exists, which is now unlikely to be triggered, except perhaps by heavy triggers in steep, shallow, rocky terrain where more facetting has taken place.

Problems

Storm Slabs

An icon showing Storm Slabs
New snow may not bond well to the old snow surface. Winds are also likely to transport snow onto downwind slopes, leaving wind slabs behind.
Note recent avalanche activity.>Avoid open slopes with any steepness over 35 degrees.>Avoid freshly wind loaded features.>Whumpfing, shooting cracks and recent avalanches are all strong indicators of an unstable snowpack.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 5

Valid until: Jan 7th, 2013 2:00PM