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Backcountry Avalanche Advisory

As of Tuesday, Dec. 18


Alpine:  Considerable trending HIGH on Wednesday

Treeline : Considerable

Below Treeline: Moderate

Travel Advisory: We received about 37 cm of new snow in the storm that arrived for Dec 16. The snow was accompanied by strong winds from the east and southeast, resulting in loading low in many of the start zones. The Dec. 4 th rain crust is buried an average of about 60 cm deep, but it is still very much in evidence on some ridgelines and windward slopes. The forecast storm for Dec. 19 th should add to the coverage. In rocky terrain where the snowpack is shallow, the snow is rotten and sugary — be careful if you are traveling under rock bands, as the snow may not support your weight.

Avalanche Activity: Ski cutting and explosive testing carried out Dec. 17 produced numerous avalanches to size 2.0 that were running for the most part in the storm snow. Two anomalies stepped down to the Dec. 4 rain crust. The slab was easily triggered and ski cutting appeared to be the most effective control method. Earlier in the week there were reports of some isolated deeper slab releases that were pulling down to the early November crust.

Snowpack: The Dec. 4th rain crust is getting buried, but can still be found on the surface in some wind-affected terrain. Depending on aspect and elevation there is a variety of layers sitting above the crust, including lower density storm and facetted crystals. As previously mentioned, rocky terrain has a facetted snowpack and may produce deeper slab avalanches when a sufficient load arrives.

Weather:  Flurries today and tonight will give way to a vigorous system that will arrive onshore on Wednesday morning bringing heavy snowfall and high winds. Flurries will linger behind the front on Thursday, with sunny breaks forecast for Friday. The extended outlook is calling for another system on Saturday. Freezing levels are expected to be at or near the valley bottom throughout this period.

Conditions may vary and can change rapidly. Check for the most current conditions before heading out into the backcountry. Daily updates for the areas adjacent to Whistler-Blackcomb are available at 604-938-7676, or surf to where there is also a link to the CAA public avalanche bulletin, or call 1-800-667-1105.

– Whistler Mtn. Snow Safety