Avalanche Forecast

Issued: Dec 11th, 2016 3:33PM

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

Avalanche Canada rbuhler, Avalanche Canada

Lingering wind slabs are expected to be the main concern at the moment.  Continually assess conditions as you travel and use extra caution as you transition into wind affected terrain.

Summary

Confidence

Moderate -

Weather Forecast

Dry conditions with a mix of sun and cloud is expected for Monday but lingering flurries are possible in the morning. Treeline temperatures are expected to be around -12C and alpine winds are forecast to be light from the north. On Tuesday and Wednesday, sunny and dry conditions are expected. Treeline temperature are expected to remain around -12C and alpine winds are generally expected to remain light from the north.

Avalanche Summary

On Saturday, ski cutting was producing very soft slabs, mostly likely in leeward terrain features. A few natural size 1 loose avalanches were also observed. On Friday, one natural size 1 wind slab was reported. Ski cutting was also producing size 1 wind slabs in isolated terrain features that were loaded by recent strong northeast winds. A MIN post from Friday shows a 30cm thick wind slab which was triggered by a skier at treeline. On Monday, lingering wind slabs may still be reactive to human triggering. Wind slabs are possible on all aspects in wind exposed terrain due to shifting wind direction over the last few days.

Snowpack Summary

Around 20cm of new low density snow has buried the heavily wind affected surfaces from the strong outflow winds last week. The old surface is highly variable and may include hard wind pressed or scoured areas, old wind slabs, weak faceted snow, or small surface hoar. Expect the new snow to be bonding poorly with this interface. The cold temperatures appear to be preserving the old wind slabs from the end of last week and they still may be reactive to human triggering in isolated areas. In high elevation terrain, moderate southwest winds over the weekend may have redistributed some of the new storm snow and soft slabs may exist in immediate leeward features. The widespread mid-November crust 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.

Problems

Wind Slabs

An icon showing Wind Slabs
Winds slabs may be lingering on all aspects due to recent winds from a variety of directions. These wind slabs may be sitting over a weak layer which could increase their reactivity.
Use ridges or ribs to avoid pockets of wind loaded snow.Be cautious as you transition into wind affected terrain.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Dec 12th, 2016 2:00PM

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