Human-triggered persistent slabs remain a concern at treeline and above where no crust exists. Opt for low-consequence terrain away from overhead hazard to increase your safety margin.
As temperatures rise, large cornice falls are becoming a concern. They can potentially trigger persistent slab avalanches on the slopes below.
Several weak layers persist in the snowpack. These layers have produced recent large avalanches and have been triggered remotely from some distance away.
On Sunday, warmer temperatures and sunshine triggered a few natural cornice falls, pulling slabs on the slopes below up to size 2.5. Wet loose were also reported up to size 1.5 from steep sunny slopes. Evidence of large, persistent slab avalanches from last week continues to be reported. Many failed on the buried persistent weak layers.
Where a thick, supportive surface crust is found, we expect that triggering avalanches on buried weak layers is unlikely.
Variable wind affect and wind slab covers open terrain at upper elevations. A crust is found up to 1400 m and higher on solar slopes. New surface hoar up to 10 mm has formed on treeline and alpine features sheltered from the sun and wind.
Three layers of concern currently exist in the upper-mid snowpack. Surface hoar and a crust that formed in mid-March can be found 30 to 70 cm below the snow surface. Below this, another layer of surface hoar that formed in early March can be found at a depth of 60 to 100 cm. Additionally, a layer of facets, surface hoar, and/or a crust from mid-February is buried 120 to 200 cm deep.
The remainder of the snowpack is well consolidated, and there are no current concerns.
Tuesday Night
Clear. 20 to 30 km/h north ridgetop wind. Treeline temperature -4 °C. Freezing level at valley bottom.
Wednesday
Mostly sunny. 20 to 30 km/h northwest ridgetop wind. Treeline temperature -3 °C. Freezing level 1200 m.
Thursday
Mostly sunny. 10 to 20 km/h west ridgetop wind. Treeline temperature -1 °C. Freezing level 1400 m.
Friday
Mix of sun and clouds. 20 to 30 km/h southwest ridgetop wind. Treeline temperature 0 °C. Freezing level 1600 m.
More details can be found in the Mountain Weather Forecast.
