Avalanche Forecast

Issued: Dec 2nd, 2013 7:50AM

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

Avalanche Canada Peter, Avalanche Canada

Data is very limited from the region. Please send your field observations to forecaster@avalanche.ca.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Tonight and Tuesday: Clear and cold. Expect mountaintop temperatures to dip to -20 or -25 overnight. Ridgetop winds are moderate to strong from the Northwest-Northeast. Outlook: Continued cold and clear weather should be the story all week. Alpine temperatures should hover between -20 and -30, and winds should remain moderate from the North-Northeast.

Avalanche Summary

No recent avalanches have been reported but incoming field data is still very limited. Watch for new touchy wind slabs to form on South and West aspects in response to cold outflow winds.

Snowpack Summary

Variable snowpack depths are being reported across the region but typically 30-60 cm of storm snow has fallen on approximately 1m of old, well-settled snow. The new storm slab will increase in reactivity and destructive potential as it deepens or in areas where it has been redistributed and compressed by wind. The storm slabs overlay a variety of old snow surfaces including (1) winds slabs and wind scoured areas in the alpine and exposed areas at treeline, (2) sun crusts on steep south facing slopes, and (3) surface hoar in sheltered areas around treeline elevation and below.There are still two layers of concern within the mid/lower snowpack: the early November surface hoar is down roughly half way (70-90cm) and the October rain crust is near the ground. While these layers have recently become dormant, the weight of the new storm snow may cause these layers to reactivate in isolated areas causing large, destructive avalanches. The October crust can be found in the alpine on north aspects (likely east and west as well). The early November surface hoar appears to be spotty and drainage specific.

Problems

Storm Slabs

An icon showing Storm Slabs
New storm snow may not bond well to the underlying surface, which may include surface hoar or a sun crust. Strong northerly winds may form touchy new wind slabs in exposed South to West facing terrain.
Be cautious as you transition into wind affected terrain.>Avoid travelling in areas that have been reverse loaded by winds.>Avoid open slopes and convex rolls at and below treeline where buried surface hoar may be preserved.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

2 - 5

Persistent Slabs

An icon showing Persistent Slabs
The October rain crust and the early November surface hoar are lurking deeper in the snowpack. Smaller storm avalanches could step down to one of these layers creating a large full-depth avalanche.
Be aware of the potential for full depth avalanches due to deeply buried weak layers.>Avoid convexities or areas with a thin or variable snowpack.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 5

Valid until: Dec 3rd, 2013 2:00PM