Wind slabs might be reactive to human triggers, especially on steep, unsupported slopes and roll-overs. Assess the snowpack when you transition into wind affected terrain.
Fresh wind slabs might form in isolated terrain features and where soft snow is available for transport. Older wind slabs formed by west and northwest wind might still be reactive to human triggers, especially where they overlie feathery surface hoar.
Wednesday night: Increasing clouds, trace of new snow, moderate northwest wind, alpine low -9 °C, freezing level at valley bottom.
Thursday: Cloudy, up to 5 cm snow, moderate westerly wind, alpine high -6 °C, freezing level at valley bottom.
Friday: Cloudy, 5-10 cm snow, strong southwest wind, alpine high -1 °C, freezing level around 1200 m.
Saturday: Mostly cloudy with some sun, 5-10 cm snow, moderate to strong southwest wind, alpine high -3 °C, freezing level around 900 m.
A few small wind slabs in isolated terrain were triggered by skiers on Tuesday.
A skier triggered a small wind slab on a northeast facing slope in the alpine on Monday. Numerous small natural wind slab avalanches were observed as well as a large (size 2) wind slab avalanche 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 (size 2) was observed on a steep alpine slope and likely released on a crust that was buried mid-February. Many small wind slab avalanches released naturally in the alpine and at treeline. Riders triggered a small 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.
The snow surface is heavily wind affected in wind exposed areas. On solar aspects, the snow surface has a crust. Dry snow can be found on north and east aspects above 1400 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.
