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Avalanche Forecast

Dec 16th, 2016–Dec 17th, 2016
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
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
1: Low
The avalanche danger rating below treeline will be low
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: North Columbia.

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

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: Cloudy, alpine temperatures -16, ridgetop winds from the West 30-60 km/hr, snow 5 cm. Sunday: Cloudy, alpine temperatures -12, ridgetop winds SW 50-60 km/h, snow 5-10 cm.Monday: Cloudy, alpine temperatures -8, ridgetop winds SW 40-80 km/h, snow 15-20 cm.

Avalanche Summary

Recent avalanche observations include a natural cornice fall up to size 1.5, not triggering a slab on the slope below and loose dry sluffing up to size 1.5 from steeper terrain features. On Wednesday, a recent glide crack released up to size 3 from steep south facing terrain around 2500 m. Strong winds over the weekend will likely build new wind slab problems that may be easily triggered by light loads like a skier or snowmobiler.

Snowpack Summary

Recent wind has formed isolated wind slabs on a variety of aspects in the alpine. The surface snow has been faceting due to the cold temperatures, and some surface hoar has been developing in sheltered locations. The mid-pack has been reported to be well settled above a crust that was buried in mid-November. This crust is be buried 90-160cm deep, depending on elevation and previous exposure to winds. Snowpack tests on the crust have shown variable results from sudden to no result. If you dig down to the crust, watch for facets (sugary crystals) developing above and below. This may provide a hard surface with a weak sliding layer in the future.

Avalanche Problems

Wind Slabs

Forecast strong winds may build new wind slabs. 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