Wet loose avalanches may start small but can trigger deeper slabs.
Manage exposure to overhead hazards where consequences are greatest.
Dry snow at upper elevations was redistributed by past moderate to strong winds. New wind slabs have likely developed over a previous surfaces of old wind slab, hard wind pressed snow and/or a crust.
A buried layer of facets in the snowpack is expected to be more reactive in wind-affected thin rocky terrain features. Triggering of this layer is less likely where a supportive crust is present.
Once the sun comes out, expect wet and loose dry avalanche activity to occur rapidly on steep south aspect terrain.
On Wednesday, a large (size 3) persistent slab avalanche was reported west of the forecast region. The avalanche ran on an east aspect in the alpine. This observations indicates that the persistent slab problem continues to a concern in this forecast region.
Numerous size 2 to 2.5 wind slab avalanches occurred over the past weekend.
10 to 15 cm of new snow has fallen over the past week.
This new snow overlies wind affected snow, with wind slabs in lee terrain features. Wind slabs remain reactive and are slow to bond to previously heavily wind pressed surfaces. A surface crust can be found up to 1500 m.
Below this, a layer of facets from early February and a thick crust from late January are at a similar depth between 70 and 110 cm deep. This layer remains possible to trigger with large loads and is likely found more easily on north facing slopes.
Thursday Night
Clear skies. 20 km/h west ridgetop wind. Treeline temperature -9 °C.
Friday
Mix of sun and clouds. 1 to 2 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -9 °C.
Saturday
Mix of sun and clouds. 2 to 5 cm of snow. 30 km/h west ridgetop wind. Treeline temperature -9 °C.
Sunday
Mix of sun and clouds. 3 to 5 cm of snow. 30 km/h southwest ridgetop wind. Treeline temperature -9 °C.
More details can be found in the Mountain Weather Forecast.
