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 60 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 widespread avalanche cycle occurred last weekend on the late-January surface hoar layer, producing avalanches up to size 2.
While avalanche activity has gradually decreased since the weekend, several smaller natural and human-triggered slab avalanches (size 1–1.5) have occurred across the region, also failing on the late-January layer.
In general, recent avalanche activity has been most common near treeline, on a variety of aspects.
Either a thin surface crust or moist snow is expected Friday morning, depending on the strength of the overnight freeze.
Continued warm temperatures and sunny skies will likely lead to moist snow on all aspects and at all elevations by the end of the day.
Approximately 30 to 40 cm of recent snow continues to settle into a cohesive slab over a widespread late-January weak layer of surface hoar on a melt-freeze crust, with up to 15 cm of weak, faceted snow immediately below the crust.
The mid and lower snowpack remain well settled, with no significant concerns at this time.
Thursday Night
Clear skies. 20 km/h southwest ridgetop wind. Treeline temperature 5 °C. Freezing level 3400 m.
Friday
Sunny. 30 km/h southwest ridgetop wind. Treeline temperature 3 °C. Freezing level 3000 m.
Saturday
Mix of sun and clouds. 5 to 15 mm of precipitation as snow or rain at treeline. 40 km/h southwest ridgetop wind. Treeline temperature -1 °C. Freezing level 1800 m.
Sunday
Mostly cloudy. 10 to 20 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -2 °C. Freezing level 1600 m.
More details can be found in the Mountain Weather Forecast.
