The forecast calls for lots of sun with only a few clouds! The wind will pick up in the afternoon and form fresh wind slabs where soft snow is available for transport.
The wind will switch to west and become strong in the afternoon. Fresh wind slabs will form where soft snow is available for transport.
Older wind slabs from previous extreme west and northwest wind might still linger and be reactive to human triggers, especially where they overlie feathery surface hoar.
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.
Tuesday night: Clear with cloudy periods, trace of new snow, light northeast wind, alpine low -15 °C, freezing level at valley bottom.
Wednesday: Mostly sunny with some clouds, light east wind switching to strong west wind in the afternoon, alpine high -8 °C, freezing level at valley bottom.
Thursday: Cloudy, 5-10 cm snow, strong west and southwest wind, alpine high -6 °C, freezing level at valley bottom.
Friday: Mainly cloudy, 5-10 cm snow, strong to extreme southwest wind, alpine high -1 °C, freezing level around 1200 m.
A skier triggered a small size 1 wind slab on a northeast facing slope in the alpine. Numerous small natural wind slab avalanches were observed as well as one large wind slab avalanche of size 2 in steep north facing alpine terrain. A deep persistent slab of size 3 was observed to the east, outside the forecasting region.
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 is heavily wind affected in wind exposed areas. On solar aspects, the snow surface has a crust below around 1000 m. 10-20 cm of snow overlie a layer of feathery surface hoar that was buried at the beginning of March. This layer can be found in isolated, wind sheltered areas. It was reactive to skier traffic in the north of the region on Monday.
The mid-February crust is now buried 40-60 cm deep. 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.
