Stormy conditions continue this weekend. Both natural and human-triggered avalanches are very likely, with the potential for very large avalanches to reach the valley bottom. Travel in avalanche terrain is not recommended, including travel in runout zones.
A touchy weak layer is buried near the bottom of the snowpack. This layer has been responsible for many large, destructive avalanches in the region. The consequence of triggering this layer would be severe. The likelihood of triggering this layer will be elevated during the stormy conditions on Saturday.
Intense stormy conditions continue, with another 40 to 60 cm of snow possible Friday night into Saturday and strong southwest wind. Touchy storm slabs will be reactive to both human and natural triggers on Saturday. Travel in avalanche terrain is not recommended.
FRIDAY NIGHT: Cloudy with snowfall, accumulation 30 to 50 cm, moderate southwest wind, alpine temperature -5 C, freezing level 1500 m dropping to 500 m by the morning.
SATURDAY: Cloudy with snowfall, accumulation 10 to 20 cm, moderate to strong southwest wind, alpine temperature -10 C, freezing level 700 m.
SUNDAY: Cloudy with snowfall, accumulation 20 to 40 cm, moderate southwest wind, alpine temperature -7 C, freezing level 800 m.
MONDAY: Cloudy with snowfall, accumulation 10 to 20 cm, moderate southwest wind, alpine temperature -7 C, freezing level 800 m.
On Friday, persistent slab avalanches released to ground in below treeline elevations, on the weak and sugary faceted grains described in the snowpack summary.
On Thursday, many large storm and persistent slab avalanches were triggered by explosives and naturally. Cornices were also reactive to explosives.
These types of avalanches are expected to occur this weekend as the storm continues.
Intense snowfall continues in the region, forming dangerous avalanche conditions. Storm slab avalanches around 30 to 60 cm thick are widespread and they may overly a touchy weak layer of surface hoar. Thicker slabs will be found near ridges at higher elevations, as the snow is falling with strong southwest wind.
Near the bottom of the snowpack around 150 to 200 cm deep, sugary faceted grains and a hard melt-freeze crust exist from mid-November, which is an indicative snowpack setup for large and destructive avalanches. The likelihood of natural and human-triggered avalanches on this layer remains elevated with the rapid loading occurring during this stormy period.
