Confidence
Fair - Intensity of incoming weather is uncertain
Weather Forecast
A Southern flow with embedded troughs will continue to dominate the region through to Monday, bringing additional snowfall amounts. Arctic air has moved into the region creating weak alpine temperature inversions. Valley bottom temperatures steady at -20.Saturday night into Sunday: Snow amounts 10-15 cm overnight with an additional 5 cm tomorrow, ridgetop winds light from the South, alpine temperatures near -15 with a weak inversion during the day. Monday: Light snowfall amounts in the morning, ridgetop winds light from the SE, and alpine temperatures near -15.Christmas Day: Mainly dry with sunny periods, ridgetop winds light from the South, and alpine temperatures -12.
Avalanche Summary
On Friday, a size 2 avalanche was triggered by a skier on a northeast aspect at 1900 m. The fracture depth was 30 cm and the slide ran for 150 m.
Snowpack Summary
Variable amounts of new snow have given storm slab depths ranging from approximately 20 to 50 cm. Extensive wind transport has built stiff wind slabs overlying lower density storm snow and may be touchy to rider triggers. Large wind drifts can be found in many areas behind exposed terrain features. Two crusts have been identified in the snowpack: one close to the ground that formed in early November and one around 90 cm below the surface, which formed in early December. Snowpack tests indicate these crusts are well bonded to the snow above and below.
Problems
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.