Fresh windslabs are building over recently buried surface hoar, facets, and sun crust. Expect the new snow to be sensitive to human triggering in exposed lee terrain.
Knee tweaking and bone-snapping hazards may be buried just below the surface of the early season snowpack, travel with caution.
Weak, widespread facets, along with surface hoar in sheltered areas, were recently buried by ~15cm of new snow. Reactivity will increase with continued wind transport.
Expect windslabs to become reactive in exposed terrain with the strong SW winds forecast for Thursday.
There were a few small slab avalanches in the steep terrain east of Rogers Pass overnight into Wednesday - MacDonald Gully #9 size 2.0, Tupper Minor size 1.5, and Tractor Shed East size 1.5.
SW winds will redistribute up to 20cm of recent snowfall, forming fresh windslabs. These overlie surface hoar (5-30mm), facets, and crust on solar aspects. The buried surface hoar is largest at and below treeline.
The early season snowpack is thin and variable, with an average depth of 60cm below treeline, 80cm at treeline, and up to 120cm in the alpine in loaded areas. These values are below threshold for burying hazards, covering creeks, and bridging crevasses.
Gradually increasing temps and winds into Thursday, with alpine highs reaching -2*C, and Moderate to Strong SW ridgetop winds.
More snow begins early Friday (up to 15cm through the day) and continues through the weekend. Storm snow totals (Tuesday-Sunday) may reach 50cm by the end of the weekend.
More details can be found in the Mountain Weather Forecast.
