Warm temperatures continue to form cohesive slabs over a widespread weak layer.
The likelihood and potential size of slab avalanches largely depend on the depth of this layer.
Warm temperatures continue to form cohesive slabs over the late-January weak layer. Burial depth varies widely (roughly 10 to 40 cm); where it is deeper, the likelihood of triggering larger, more destructive avalanches increases.
Clear skies and above-freezing temperatures throughout the day will weaken the upper snowpack and potentially lead to wet loose avalanche activity.
A natural avalanche cycle occurred last weekend with numerous slab avalanches up to size 2. All of these appeared to fail on the late-January surface hoar/crust/facet layer outlined in the snowpack summary.
While avalanche activity has largely decreased since last weekend, several small (size 1 to 1.5) human-triggered avalanches have occurred throughout the week on a variety of aspects at treeline and above.
Either a thin surface crust or moist snow is expected Friday morning, depending on the strength of the overnight freeze.
Continued above-freezing temperatures and sunny skies will likely create moist snow surfaces on all aspects and at all elevations by Friday afternoon.
Approximately 10 to 30 cm of snow continues to settle into cohesive slabs over the late-January weak layer. This layer consists of a melt-freeze crust of variable thickness, with a possibility of surface hoar on top and faceted snow above and/or below the crust.
The mid and lower snowpack is generally well settled, with no significant concerns.
Thursday Night
Clear skies. 30 km/h west ridgetop wind. Treeline temperature 4 °C. Freezing level 3500 m.
Friday
Sunny. 40 km/h west ridgetop wind. Treeline temperature 3 °C. Freezing level 3200 m.
Saturday
Mostly sunny. 1 to 3 mm of precipitation as snow or rain at treeline. 50 km/h west ridgetop wind. Treeline temperature 0 °C. Freezing level 1900 m.
Sunday
Mostly cloudy. 10 to 30 mm of precipitation as snow or rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1800 m.
More details can be found in the Mountain Weather Forecast.
