Avalanche Forecast

Issued: Dec 19th, 2016 4:40PM

The alpine rating is high, the treeline rating is high, and the below treeline rating is considerable. Known problems include Storm Slabs and Loose Dry.

Avalanche Canada swerner, Avalanche Canada

More snow, strong winds and warmer temperatures are driving the danger ratings. Its a good time to stick to simple non-avalanche terrain.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain on Tuesday

Weather Forecast

The Interior is under a strong zonal flow that is responsible for pushing out the cold air and bringing in the snow! We can expect to see an additional two - three systems move across the region through the forecast period.Tuesday: Snow 10-20 cm with freezing levels rising to 900 m. Alpine temperatures -10 and ridgetop winds West 35-45 km/hr.Wednesday: Snow 5-10 cm with freezing levels dropping to valley bottom. Alpine temperatures -11 and ridgetop winds SW 50 km/hr.Thursday: Snow 5 cm with alpine temperatures -14. Ridgetop winds South 15-35 km/h.

Avalanche Summary

Several natural storm slabs up to size 2 were reported on Monday, however; I suspect a widespread natural avalanche cycle occurred as some areas received up to 50 cm!! Given the weather forecast we can expect to see avalanche activity continue Tuesday.

Snowpack Summary

20-50 cm of new storm snow sits above a plethora of old snow surfaces including stiff wind affected snow, faceted (sugary) crystals and surface hoar crystals that formed in locations sheltered from the wind. The new storm snow will likely have a poor bond to these. The mid-November crust is buried down 70-150 cm and produces variable results in snowpack tests. Moderate results may be more likely in shallower snowpack areas, and deeper snowpack areas may be more likely to show no results on this layer. Tracking and monitoring this potentially weak interface is crucial especially as we move forward into this stormy period where the snowpack will see more load.

Problems

Storm Slabs

An icon showing Storm Slabs
New storm slabs will be building through the day. Watch for conditions that change with aspect and elevation, especially on wind loaded slopes and terrain features.
Avoid avalanche terrain during periods of heavy loading from new snow and wind.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 3

Loose Dry

An icon showing Loose Dry
Loose dry avalanches from steeper slopes and terrain features may entrain enough mass to bury you.
Avoid traveling on ledges and cliffs where small avalanches may have severe consequences.Watch for terrain traps where small amounts of snow will acumulate into deep deposits.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely - Very Likely

Expected Size

1 - 2

Valid until: Dec 20th, 2016 2:00PM

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