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Avalanche Forecast

Dec 21st, 2016–Dec 22nd, 2016
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
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: Sea To Sky.

As this past week's storm snow continues to settle it will still be important to evaluate the bond between the old snow surface and the new snow. There is still potential for a weak sliding layer in isolated sheltered areas.

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Thursday: Flurries, accumulation 5-10cm / Moderate southwest wind / Alpine temperature -4Friday: Mainly cloudy with isolated flurries / Light northeast wind / Alpine temperature -7Saturday: Sunny with cloudy periods/ Light north wind / Alpine temperature -10

Avalanche Summary

Recent reports from Monday and Tuesday indicate numerous explosive and a few skier triggered storm slab and wind slab avalanches to size 2 in the alpine and treeline at the storm snow/old snow interface . There were also reports of a few remotely triggered avalanches from thin wind scoured ridge crests into adjacent steeper loaded slopes. I would suspect there to be continued potential for skier and rider triggering with some recent very strong winds at upper elevations and a possible weak bond at the storm/old snow interface with buried surface hoar in isolated sheltered areas.

Snowpack Summary

30-50cm of new snow overlies the previous variable snow surface from last week, which includes hard wind pressed or scoured areas, old wind slabs, weak faceted snow, or surface hoar. Moderate to strong southwest wind has redistributed this new snow to form windslabs in the lee of terrain features in the alpine and treeline. The widespread mid-November crust is typically down 1-2m in the snowpack. Recent snowpack and explosive tests have shown the crust to be unreactive, but it could remain a problem in shallow alpine start zones.

Avalanche Problems

Wind Slabs

Recent strong southwest winds have created touchy wind slabs in the lee of terrain features
Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

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

Elevations: Alpine, Treeline.

Likelihood: Possible - Likely

Expected Size: 1 - 3

Storm Slabs

Recent new snow sits on top of a variety of potential weak sliding layers.
Dig down to find and test weak layers before committing to a line.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood: Possible

Expected Size: 1 - 2