Avalanche Forecast

Moderate - Due to the number of field observations

Dry with gradually warming alpine temperatures during the week. Cold in the valley bottoms. TUESDAY: Mix of sun and cloud. Ridge wind light west. Alpine temperature -8. Freezing level surface.WEDNESDAY: Cloudy with sunny breaks. Ridge wind light west. Alpine temperature -5. Freezing level surface.THURSDAY: Mix of sun and cloud. Ridge wind light southwest. Alpine temperature -3. Freezing level surface.

On Monday, a machine triggered Size 1.5 persistent slab avalanche was reported running on the mid December surface hoar layer, down 35 cm at that location (1700m). Even mountain goats looked like they were triggering avalanches! See the details here in the MIN post. On Sunday a Size 2 persistent slab (stepping down to late November crust/facets) was intentionally triggered on an east aspect near 2000m in the south of the region.On Saturday several natural and human triggered storm slab avalanches to Size 2 were reported on a wide variety of aspects and elevations. Furthermore, several persistent slab avalanches to Size 1.5 were reported (with some remote-triggered by skiers). Earlier last week, a larger persistent slab (Size 2) was triggered low on a slope that propagated up and across the slope on a 50 cm deep crust. This highlights the potential for persistent slab avalanches to have wide propagations.

Up to 45 cm of snow fell on Thursday into Saturday morning, with generally light winds. The main question in the snowpack surrounds the mid-December layer sitting beneath the recent snow. This layer includes crusts on solar aspects and feathery surface hoar in sheltered terrain at and below treeline, and has consistently shown its reactivity, even on small features below treeline. The lower snowpack is composed of mostly soft sugary snow and a few early season crusts that have not produced significant test results recently.