Avalanche Forecast

No Rating - Uncertainty is due to the fact that deep persistent slabs are particularly difficult to forecast.

WEDNESDAY NIGHT: Light flurries with up to 5 cm of new snow, 40-60 km/h wind from the southwest, alpine temperatures drop to -10 C.

THURSDAY: Scattered flurries throughout the day with 5-10 cm of new snow, 50-80 km/h wind from the west, alpine high temperatures around -4 C.

FRIDAY: Isolated flurries with up to 5 cm of new snow, 30 km/h wind from the west, alpine high temperatures around -6 C.

SATURDAY: Mix of sun and cloud, 30 km/h wind from the west, alpine high temperatures around -8 C.

Recent avalanche activity is limited to a few wind slab avalanches (size 1-2) triggered with explosives. Avalanche activity has seemed to quiet down since the weekend, when several large persistent slab avalanches (size 2-3) were reported at treeline and alpine elevations. Most of them were also triggered with explosives, but one was remotely triggered as a person walked on low angle terrain above the slope. These avalanches have run on buried crusts and weak layers ranging from 40-100 cm deep. This type of activity is indicative of a weak snowpack structure capable of producing large avalanches.

New snow and wind will likely form fresh wind slabs at upper elevations. In sheltered areas 20-30 cm of snow from last weekend is gradually settling. Weak snow can be found 40-100 cm deep around crust layers that formed in November and October. These persistent weak layers have recently produced large avalanches. We are uncertain about the spatial distribution of these layers, but suspect they are widespread at upper elevations where early season snow existed. Snowpack depths range between 50-100 cm at higher elevations and taper rapidly below treeline.