It's going to be a sunny day! Wind slabs were formed by extreme west and northwest wind on Sunday and might still be reactive to human triggers.
Extreme west and northwest wind on Sunday formed wind slabs in the alpine and at exposed treeline. Wind slabs might be found farther down slope than expected due to the strength of the wind.
Cornices are large and can become weak with sun exposure. Caution around slopes that have cornice hazard above. Keep in mind that firm cornices can pull back into flat terrain at ridgetop if they fail.
Monday night: Clear with cloudy periods, light northeast wind, alpine low -10 °C, freezing level at valley bottom.
Tuesday: Mainly sunny, moderate northeast wind, alpine high -9 °C, freezing level at valley bottom.
Wednesday: Mix of sun and cloud, light variable wind, alpine high -8 °C, freezing level at valley bottom.
Thursday: Cloudy, up to 5 cm snow, strong west wind, alpine high -6 °C, freezing level at valley bottom.
On Sunday, a large natural slab avalanche of size 2 was observed on a steep alpine slope and likely released on a crust that was buried mid-February. Several small (size 1) wind slab avalanches released naturally in the alpine and at treeline. Riders triggered a small (size 1.5) wind slab on a convex roll in the alpine. The avalanche was about 30 cm deep. Warm temperatures triggered numerous small loose wet avalanches in the alpine and at treeline.
A large (size 2) slab avalanche was likely triggered by a failed cornice on Saturday. Small loose wet avalanches were reported on Friday.
The snow surface has a crust below around 900 m on solar aspects. 40-60 cm of well settled and bonded snow sits on top of the mid-February crust. Though this layer has not produced avalanche activity, professionals in the area are still treating it with suspicion. Cornices are looming in alpine areas.
The lower snowpack is well bridged by the mid-February crust, and triggering avalanches below this layer is unlikely at this time.
