Assess the bond of the new snow to the old surface, reactive slabs may overlie a buried weak layer.
You can always choose sheltered, mellow terrain.
Northwest winds have built reactive slabs on lee terrain features. Watch steep, convex rolls and open slopes, and areas near ridgetop. Use caution at treeline and in other features where surface hoar may be preserved below the slabs.
Numerous size 1-1.5 slab avalanches were reported on Saturday. Many of these avalanches were triggered remotely, failing on the buried weak crystals detailed in the Snowpack Summary. Some riders felt a whumpf when approaching the slope. Thanks for the MIN reports.
A size 2 natural wind slab was also observed near Terrace.
Looking ahead, expect slabs to remain reactive to human-triggering. Use caution at treeline and in other features where surface hoar may be preserved.
In most areas, 15 to 30 cm of new snow has buried a layer of weak, feathery crystals. Expect to find reactive wind slabs on north- through east-facing slopes, where southwest winds have redistributed this new snow.
This overlies firm wind-affected surfaces or 10 to 30 cm of settled dry snow in sheltered areas. Below this is a thick and hard melt-freeze crust extending up to approximately 1700 m. This crust is just buried by the 15 to 30 cm of new snow at lower elevations.
Sunday Night
Partly cloudy. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -8 °C.
Monday
Cloudy. 30 to 40 km/h northwest ridgetop wind. Treeline temperature -4 °C.
Tuesday
Few clouds. 30 to 40 km/h northeast ridgetop wind. Treeline temperature -4 °C.
Wednesday
A few clouds. 40 to 50km/h northeast ridgetop wind. Treeline temperature -4 °C.
More details can be found in the Mountain Weather Forecast.
