Arctic air will bring cold temperatures to the forecast region this weekend. Be prepared with extra warm gear, as even a minor setback could become very serious in these temperatures.
A combination of new snow and Moderate winds have formed new wind slabs in the alpine. If wind values increase this weekend we can expect this problem to be more sensitive and widespread.
The lower snowpack is comprised of weak facets and depth hoar with the upper snowpack forming a 40 to 90 cm thick slab above. NW winds, snow and a big temperature drop this week may make this layer more sensitive to triggering for the next few days...
Both ski hills reported new soft slab development in the alpine that was reactive to ski cutting. No results were bigger than size 1. One natural avalanche size 1.5 was reported from the Lake Louise backcountry, this occurred during a short period of Strong wind values Friday morning.
10 to 15cm of new snow Friday with little new wind effect overlays wind slabs in the alpine. Below this, the upper snowpack contains weak layers 20-40 cm deep (Jan. 4th) and 30-60 cm deep (Dec. 17th) that are generally unreactive. The Nov 16 deep persistent layer is down 40-90 cm and continues to produce sudden test results. In areas west of the divide, these layers are generally deeper and more spread apart in the snowpack.
A ridge of high pressure will build Friday, bringing clear skies and colder temperatures for the weekend. As the cooling trend begins, we will see a 20-degree shift, with temperatures near -25°C by Saturday morning. Ridge winds will be in the moderate range Saturday and increase to strong by Sunday.
