Avalanche Forecast

Issued: Dec 5th, 2013 8:48AM

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.

jfloyer, Avalanche Canada

South Rockies.

Observations are limited right now. If you've been out, please tell us what you see by dropping us an email at forecaster@avalanche.ca

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Extremely cold, dry weather will persist through the weekend, with lows down to -35C. Some cloud on Friday and Sunday; Saturday currently looks clear. Winds initially light but picking up on Saturday afternoon to become strong NW at ridgetop on Sunday.

Avalanche Summary

No reports of avalanche activity.

Snowpack Summary

The limited information we have from this regions suggests treeline snowpack depths vary from around 60 cm to 120 cm depending on location. Anywhere from 40 to 70 cm new snow fell with the most recent storm. Initially temperatures were relatively warm, then they cooled dramatically. As a result, the new storm snow is generally "right-side-up", meaning lower density snow sits above denser snow below. Strong northerly winds following the storm created wind slabs on exposed southern slopes. One recent reports has suggested it is becoming more difficult to trigger these wind slabs. While this is consistent with what we commonly see when the wind subsides and temperatures dive into the -20's, the lack of observations would make me approach steep, wind loaded terrain with a lot of caution right now. At or near the base of the snowpack, I suspect you will find sugary facets. The chance of triggering this layer is quite small under the current conditions, but if it was to happen, it would most likely be on a steep, convex slope with a thin snowpack.

Problems

Wind Slabs

Northeast winds have developed wind slabs at higher elevations. These wind slabs may have reverse loaded terrain features that were stripped by Westerly winds during the storm.

Be careful with wind loaded pockets. Be aware of wide variation in snowpack depth>Be cautious as you transition into wind affected terrain.>

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

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 3

Persistent Slabs

Sugary facets at or near the base of the snowpack likely represent the most worrisome persistent layer. The most likely place to trigger them is on steep, convex slopes with a thin snowpack.

Avoid shallow snowpack areas on steep, convex terrain where triggering is more likely.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely - Possible

Expected Size

1 - 4

Valid until: Dec 6th, 2013 2:00PM