Avalanche Forecast

Issued: Dec 12th, 2014 8:34AM

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

jlammers, Avalanche Canada

South Rockies.

Forecast snowfall amounts for Friday night and Saturday are highly uncertain. If more than 15cm of snow falls, consider the Avalanche Danger ratings to be too low.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Forecast snowfall amounts for Friday night and Saturday are in the light to locally moderate range. That said, the collision of the moist southwest flow and the developing cool northwest pattern may deliver enhanced precipitation. Winds on Saturday will be moderate from the southwest switching to northwesterly by mid-day. Freezing levels will descend to valley bottom throughout the day.On Sunday and Monday a dry ridge of high pressure will develop bringing mainly clear skies, light northwest winds and freezing levels at or near valley bottom.

Avalanche Summary

No avalanches have been reported. If you have any observations you'd like to share, please check out the new Mountain Information Network. For details, check out: http://www.avalanche.ca/blogs/VIYBuScAAJdbdqPz/m-i-n-intro

Snowpack Summary

Light rain from the past week has saturated the upper snowpack at higher elevations, and the entire snowpack below treeline. With forecast cooling, these surfaces will likely exist as new crust.There is at least one, maybe more, problematic layers in the mid and lower snowpack. About 90cm of settled snow overlies a weak layer of facets and crusts which formed during November's dry spell. Not much is known about the reactivity of this layer, nor the slab above it, but I'd assume it exists in most alpine terrain.

Problems

Wind Slabs

Wind and new snow on Friday night may form new wind slabs in lee terrain. Windslabs may be extra touchy due to the presence of underlying crusts.

Avoid freshly wind loaded features.>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Persistent Slabs

Recent observations have been extremely limited. However, I'd assume weak crystals near the base of the snowpack are still reactive in some areas. Avalanches at this interface are more likely at higher elevations and could be destructive in nature.

Avoid slopes with variable snowpack depths. Avalanches may be triggered from thin spots around boulders or small trees.>Avoid large alpine slopes that have a deeply buried crust with facets. >

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

2 - 4

Valid until: Dec 13th, 2014 2:00PM