Heightened avalanche conditions exist in specific terrain features where weak layers in the upper snowpack are buried at prime depth for human-triggered slab avalanches.
Recent snow and wind have formed wind slabs in leeward terrain features at upper elevations. They may be especially reactive where they sit over a slippery crust.
A weak layer of surface hoar/crust/facets exists in the top 30 cm of the snowpack. It will be most sensitive to triggering in northerly upper elevation lees where the overlying snow is deepest and not capped by a more recent crust.
On Sunday, explosive control work in the alpine produced a few cornice results and several persistent slab avalanches size 1 to 1.5, failing on the January weak layer described in the snowpack summary.
In the past week, human-triggered persistent slab avalanches on this layer were reported size 1 to 1.5, most occurring at treeline and above.
10 to 15 cm of new snow settles over a complex upper snowpack.
A widespread breakable crust sits beneath the new snow, on all but alpine north aspects. Another widespread weak layer is buried 20 to 40 cm deep. It formed in late January and consists of surface hoar on a melt-freeze crust, with a thick layer of facets below. These layers are expected to become increasingly problematic as they get buried deeper.
The mid and lower snowpack remain well settled, with no significant concerns at this time.
Sunday Night
Partly cloudy. 10 km/h west ridgetop wind. Treeline temperature -4 °C.
Monday
Mostly cloudy. 30 km/h west ridgetop wind. Treeline temperature -6 °C.
Tuesday
Mostly cloudy. 1 to 4 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -7 °C.
Wednesday
Sunny. 30 km/h west ridgetop wind. Treeline temperature -6 °C.
More details can be found in the Mountain Weather Forecast.
