Recent snow needs time to settle and stabilize. And a buried weak layer continues to produce large, destructive avalanches.
A thin crust along with surface hoar and/or facets buried in early December persists roughly 100 to 200 cm deep. It appears to be of greatest concern in areas with shallow snowpacks and on wind-loaded north or east-facing slopes.
Be on the lookout for settling storm slabs and fresh wind slabs, which may be particularly reactive where they sit atop a weak layer of surface hoar crystals.
Large avalanches failing on the early December weak layers continue to be reported, although the frequency of these reports has decreased since late last week. Most recently, a natural and an explosive-triggered size 3 avalanche were observed on Tuesday, both around treeline elevations.
In addition, repeated large avalanches (size 2 and greater), including remote triggers, have been observed over the past week, underscoring the ongoing instability of this layer.
Up to 50 cm of new snow has accumulated since the weekend, with lower amounts in inland areas. Significant southwest winds have redistributed this new snow into deeper deposits in leeward terrain. A layer of weak surface hoar crystals may persist beneath the new snow, particularly on wind-sheltered slopes.
Deeper in the snowpack, approximately 100 to 200 cm below the surface, layers of crusts, faceted crystals, and/or surface hoar buried in early December remain a concern. These layers have been responsible for several large avalanches over the past week.
The lower snowpack is generally well-settled with no current concerns.
Thursday night
Cloudy with isolated flurries, trace to 10 cm of snow. 20 to 40 km/h west ridgetop wind. Treeline temperature -9 °C.
Friday
Partly cloudy. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -6 °C.
Saturday
Mostly sunny. 20 to 30 km/h northwest ridgetop wind. Treeline temperature -6 °C.
Saturday
Sunny. 20 to 30 km/h northwest ridgetop wind. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
