Avalanche Forecast

Issued: Dec 16th, 2016 3:50PM

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

Avalanche Canada swerner, Avalanche Canada

Winds will be cranking through the weekend! New wind slabs may be easily triggered by a skier or snowmobiler.

Summary

Confidence

Moderate - Timing, track, or intensity of incoming weather system is uncertain

Weather Forecast

The dominating Arctic high slides south allowing a series of Pacific frontal systems to cross the Interior through the forecast period. Strong ridgetop winds will crank up Saturday accompanied by new snow and slightly warmer temperatures Sunday and onward.Saturday: Alpine temperatures -17, ridgetop winds from the West 30-60 km/hr later in the day.Sunday: Cloudy, alpine temperatures -11, ridgetop winds SW 20-40 km/h, snow 5-15 cm.Monday: Cloudy, alpine temperatures -10, ridgetop winds SW 40-70 km/h, snow 15-25 cm.

Avalanche Summary

Recent avalanche activity includes cornice failures up to size 1.5, not triggering slabs from slopes below and size 1 skier controlled slab and loose dry avalanches from isolated terrain features. Natural avalanche activity has been isolated to wind slabs up to size 1.5 and sluffing from steep or extreme terrain. With increased winds over the weekend, the avalanche danger will rise with new wind slab problems being the primary concern.

Snowpack Summary

Due to cold and clear conditions a variety of surface snow exists from faceted (sugary) crystals to surface hoar crystals up to 8 mm in size. Variable wind effect has created wind slabs in isolated areas at upper elevations. Watch for a recently buried layer of surface hoar down 30-40cm that may develop a poor bonding layer. The depth of the mid-November crust is also variable across the region. Reports have the crust down between 100-200 cm and snowpack tests have produced a variety of results from moderate and sudden to hard and resistant, and in some cases no result. If you dig down to the crust, watch for facets developing above and/or below. This may provide a weak layer above a smooth sliding surface in the future.

Problems

Wind Slabs

An icon showing Wind Slabs
Forecast winds are increasing in strength over the weekend and may build new wind slabs at treeline and in the alpine. Watch for conditions that change with aspect and elevation.
Be careful with wind loaded pockets, especially near ridge crests and roll-overs.Be cautious of sluffing in steep terrain and avoid terrain traps below.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Valid until: Dec 17th, 2016 2:00PM

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