Archived

Avalanche Forecast

Dec 6th, 2013–Dec 7th, 2013

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

1: Low

The avalanche danger rating at treeline will be low

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Alpine

2: Moderate

The avalanche danger rating in the alpine will be moderate

Treeline

2: Moderate

The avalanche danger rating at treeline will be moderate

Below Treeline

1: Low

The avalanche danger rating below treeline will be low

Regions: South Rockies.

Confidence

Poor - Due to the number of field observations

Weather Forecast

Cold, clear weather looks set to continue through the weeekend.Saturday: Dry, temperatures around -25C, light NW winds.Sunday: Dry, temperatures around -25C, strong NW winds.Monday. A few flurries, maybe 1-2 cm new snow. Temperatures around -18C. Strong NW winds.

Avalanche Summary

No reports of avalanche activity.

Snowpack Summary

The limited information we have from this regions suggests treeline snowpack depths vary from 30 cm to 120 cm. Anywhere from 20 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. Large surface hoar crystals were buried by the recent storm snow near Elkford and likely other parts too. Strong northerly winds following the storm created wind slabs on exposed southern slopes. Recent reports suggest 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, which will surely be growing with the extremely cold temperatures. 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.

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

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 at this time. 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