Avalanche Forecast

Issued: Dec 21st, 2016 4:50PM

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

mbender, Avalanche Canada

South Columbia.

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 week sliding layer in sheltered areas.

Summary

Confidence

Moderate - Forecast snowfall amounts are uncertain

Weather Forecast

Thursday: Isolated flurries, accumulation trace / Moderate south wind / Alpine temperature -8Friday: Flurries, accumulation 5cm/ Light east wind / Alpine temperature -7Saturday: Cloudy with isolated flurries/ Light north wind / Alpine temperature -9Â

Avalanche Summary

On Monday, numerous natural slab avalanches were reported up to size 2.5 from a variety of aspects and elevations. On Tuesday a few explosives triggered and natural avalanches were reported from northerly aspects in the alpine. Natural avalanche activity may taper Thursday, however; skier triggered avalanches are still possible.

Snowpack Summary

Up to 60 cm of storm snow sits above a variety of old snow surfaces including wind affected snow, faceted (sugary) crystals, surface hoar crystals and a thin sun crust on steep solar aspects. There is a bit of uncertainty regarding how the new snow is bonding to these old snow surfaces. Two potential weak layers deeper in the snowpack may become reactive under the new load from the recent storm snow. The first being a spotty surface hoar layer down 40-80 cm and then the mid-November crust that sits 100-200 cm down. Recent test results on these layers have varied from moderate and sudden to hard and resistant, and in some cases no result.

Problems

Wind Slabs

Heavy storm snow amounts and strong southwest winds have built fresh and reactive storm slabs that sit over a variety of weak sliding layers. Rider triggering is likely.

Whumpfing, shooting cracks and recent avalanches are all strong inicators of unstable snowpack.Be cautious as you transition into wind affected terrain.Use ridges or ribs to avoid pockets of wind loaded snow.

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Dec 22nd, 2016 2:00PM