The possibility of a large persistent slab avalanche means continuing to avoid large, steep, open slopes.
These avalanches may be hard to trigger, but the consequences would be serious.
A layer of weak, sugary snow surrounding a firm crust is buried 100 to 200 cm deep. It seems to have been more likely to avalanche during warm, sunny weather, so it may be less reactive during this cooler, cloudy period.
A few large (up to size 3) natural persistent slab avalanches occurred as recently as April 10. One size 3 may have been remotely triggered. These large avalanches have occurred on northwest through east-facing slopes in the alpine.
Roughly 10 cm of new snow has buried a strong, supportive crust that is expected on the surface on all aspects at treeline and on all but north-facing terrain in the alpine.
Below treeline, a full overnight refreeze may not occur, resulting in a thin, weak, breakable crust. Wind-affected surfaces are likely in north-facing alpine terrain.
A layer of weak, sugary snow over a thick crust is buried 100 to 200 cm and continues to produce large, surprising avalanches.
Monday Night
Mostly cloudy. 2 to 4 cm of snow. 30-50 km/h southwest ridgetop wind. Treeline temperature -4 °C. Freezing level falling to 700 m.
Tuesday
Mostly cloudy. 4 to 5 cm of snow. 15-30 km/h southwest ridgetop wind. Treeline temperature -3 °C. Freezing level rising to 1250 m.
Wednesday
Mix of sun and clouds. 2 to 3 cm of snow. 20 km/h north ridgetop wind. Treeline temperature -5 °C.
Thursday
Mix of sun and clouds. 20 km/h west ridgetop wind. Treeline temperature -2 °C.
More details can be found in the Mountain Weather Forecast.
