Backcountry avalanche advisory 

As of Wednesday, Jan. 28

Alpine: Moderate Thursday, High Friday

Treeline: Moderate Thursday, High Friday

Below Treeline: Moderate Thursday, Considerable Friday

Travel Advisory: Our primary concern is the continuing possibility of large destructive avalanches being triggered at weak spots, or by large loads like falling cornices. Unsettled conditions through the middle of the week are expected to give way to a brief but intense weather system forecast to arrive on Friday. A rapid load of new snow is expected to arrive on Friday. In some very shallow areas, the December weakness that has been inactive so far may come to life. Below treeline the large surface hoar is now being buried.

Avalanche Activity: The natural avalanche activity that occurred earlier this month has tapered off as the upper snowpack has begun to strengthen. Ski and explosives testing on Tuesday within the ski area resulted in only isolated size one pockets of windslab.

Snowpack: The shallow early December snowpack was exposed to prolonged cold temperatures which caused it to become weak and faceted. Areas of depth hoar formed in shallow rocky terrain. In many alpine areas the underlying Dec. 6 raincrust adds a nice hard sliding surface. The crust/facet combination is now buried up to 200 cm below a stiff more coastal snowpack. Stability tests within the basal weakness have been variable and inconsistent. The upper pack has been gaining strength while some surface weaknesses have begun to form. Strong winds and light snowfall have added a windslab of 10-20 cm on the surface. This layer is shearing in tests and may be triggerable by the weight of a rider. As mentioned above there is large surface hoar below treeline that is now being buried, this layer may surprise people after some more snow.

Weather: Unsettled conditions on Wednesday and Thursday will change to strong winds and moderate snowfall on Friday.

- Blackcomb Snow Safety


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