Arctic air and wind chill will persist over the next couple of days. Expect fresh wind slab development with incoming strong North winds.
A combination of new snow and moderate winds have formed new wind slabs in the alpine. Forecast strong alpine wind values will likely increase this problem over the short term.
The lower snowpack is comprised of weak facets and depth hoar with the upper snowpack forming a 40 to 90cm thick slab above. Not much has changed with this layer.
Forecasters at the Ogden benches Saturday saw evidence of wind slab activity out of the steep face on Mt. Ogden, with a size 2 stepping down to a deeper weak layer. Those were probably 48 hours old. Another team at observation peak saw a size 2, deeper release which was likely over 48 hours old. Lake Louise ski hill got many size 1-1.5 wind slab avalanches with explosive control.
5-10cm of new snow over the past couple of days is being blown into wind slabs at treeline and 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 variable test results. In areas west of the divide, these layers are generally deeper and more spread apart in the snowpack.
On Sunday, expect North winds 50-60km/h diminishing to 30km/h and -20C to -25C. Continued cold temperatures on Monday then slowly warming through the week.
