Cold snow exists on high northerly slopes but this is also where persistent weak layers are most likely to be triggered.
Use low-angle terrain and avoid overhead hazard to avoid this problem.
Surface hoar and facets in the upper snowpack have recently produced large avalanches. These layers are mostly likely to be reactive at upper elevations where no surface crust has formed.
As temperatures rise, the surface snow may become moist and unstable on solar slopes, producing small loose wet avalanches.
Where a thick, supportive surface crust is found, we expect that triggering avalanches on buried weak layers is unlikely.
A natural avalanche cycle continued through Thursday, with very large slab avalanches (to size 4) failing on buried persistent weak layers. Skiers were able to remotely trigger these large slides (see photo).
A melt-freeze crust has formed on most surfaces. Dry snow persists on northerly aspects at upper elevations.
Three persistent weak layers remain notable in the snowpack and have been responsible for recent large avalanches. Surface hoar that formed in mid-March can be found 50 to 100 cm below the snow surface. Below this, another layer of surface hoar that formed in early March can be found at a depth of 100 to 150 cm. Additionally, a layer of facets, surface hoar, and/or a crust from mid-February is buried 100 to 200 cm deep.
Sunday Night
Clear. 30 km/h southeast ridgetop wind. Treeline temperature -10 °C.
Monday
Sunny. 10 to 20 km/h south ridgetop wind. Treeline temperature 0 °C. Freezing level 1500 m.
Tuesday
Cloudy with up to 5 cm of snow. 20 to 40 km/h northwest ridgetop wind. Treeline temperature -2 °C. Freezing level drops to 1000 m.
Wednesday
Mostly sunny. 30 to 50 km/h northwest ridgetop wind. Treeline temperature -4 °C.
More details can be found in the Mountain Weather Forecast.
