The wind is forecast to pick up Sunday and at upper elevations there is plenty of soft snow to blow around. Watch for fresh wind slabs forming in lee terrain features.
In areas where wind remains light and snow transport is not observed, danger may be a step lower in the alpine.
Moderate southeast to southwest wind forecast to pick up during the day will transport soft snow into fat pockets of reactive wind slab in leeward terrain features. The near surface crust offers a slick bed surface for avalanches.
A crust/facet layer sits near the base of the snowpack. It is surrounded by weak crystals and produces hard results in snowpack tests. In shallow, rocky areas in the alpine, it may remain at a depth triggerable by humans. Last week a natural cornice fall triggered a size 3 avalanche on this layer proving it's still a player. With the cooling temperatures and hardening snowpack, we don't think we will see avalanche activity on it at the moment, but it's definitely still on the radar.
Saturday night: Increasing cloud, moderate southwest ridgetop wind, freezing level valley bottom.
Sunday: Sun and cloud, isolated flurries, moderate to strong south ridgetop wind, alpine high -5C, freezing level valley bottom.
Monday: Scattered flurries, moderate southwest ridgetop wind, alpine high -8 C, freezing level 500 m.
Tuesday: 5-10 cm new snow, strong southwest ridgetop wind, alpine high -5 C, freezing level 800 m.
On Sunday, as the wind picks up, we can expect to see natural and human triggered wind slabs in lee features at upper elevations.
Since Wednesday, natural avalanche activity has been limited to loose dry sluffs of diminishing size.
A widespread natural cycle occurred during the storm Monday night through Tuesday, storm slabs size 2-3 and loose wet size 1-2.
On Tuesday December 1, a large size 3 natural avalanche was observed on a NE aspect at 2400 m in the Duffy area. It was reported as a cornice failure triggering the slope below and appeared to have slid on the early November crust near the base of the snowpack.
Have you been out and about in the mountains? If so please submit your observations to the Mountain Information Network (MIN). It doesn't have to be technical - photos are especially helpful! Thank you so much for all the great MINs submitted so far!
At upper elevations, winds are forecast to pick up during the day Sunday. The will likely redistribute into wind slabs the 10-30 cm of dry snow that sits over a crust.
