Several recent human-triggered persistent slab avalanches show that buried weak layers remain sensitive. Careful snowpack evaluation and conservative decision-making are essential.
South winds have redistributed recent snow into alpine and treeline lee terrain features. Wind slabs may be more reactive where they overlie a buried weak layer of surface hoar.
Two buried weak layers of facets and/or surface hoar that were buried mid-February and early March continue to be reactive to human triggering.
On Friday, several human-triggered persistent slab avalanches were reported up to size 2. Avalanches occurred between 1700 and 1300 m on a variety of aspects. All these avalanches failed on a weak layer found down 20 to 50 cm, a layer of large surface hoar overlying a crust that developed in early March.
Southerly winds have redistributed 20 to 50 cm of recent snow into deep pockets on lee slopes. Storm snow buried a widespread layer of large surface hoar crystals, which may sit on a crust on solar aspects and at low elevations.
A layer of facets, surface hoar and/or a crust from mid-February are buried 50 to 100 cm deep. This layer produced large natural and human-triggered avalanches throughout the previous week.
The remainder of the snowpack is well consolidated with no concerns at this time.
Saturday Night
Cloudy with light flurries, 1 to 6 cm of snow. 30 to 50 km/h south ridgetop wind. Treeline temperature -7 °C.
Sunday
Cloudy with light flurries, 1 to 3 cm of snow. 20 to 30 km/h southwest ridgetop wind. Treeline temperature -5 °C.
Monday
Cloudy with light flurries, 1 to 2 cm of snow. 25 to 35 km/h west ridgetop wind. Treeline temperature -7 °C.
Tuesday
Cloudy with light flurries, 2 to 4 cm of snow. 50 to 70 km/h southwest ridgetop wind. Treeline temperature -5 °C.
More details can be found in the Mountain Weather Forecast.
