High freezing levels and warm temperatures are maintaining elevated avalanche hazard.
Human triggered avalanches are likely until cooler weather locks in the snowpack.
Expect loose snow avalanches in steep terrain as freezing levels remain near ridgetop. As these avalanches gather mass, they could potentially step down to deeper layers within the snowpack.
20+cm of sticky wet snow and warm temperatures have created a heavy, wet slab that is reactive at all elevations on unsupported rolls and cross-loaded features. Recent avalanches have been occurring in this layer and skiing/riding is extremely difficult.
Artillery control on Monday night produced numerous loose and wet slab avalanches running full path up to sz 3.5 throughout the highway corridor. A widespread natural avalanche cycle on Sunday and Monday was also observed in the backcountry with numerous wet/loose avalanches to sz 3 observed at all elevations/aspects, gouging deeply in confined gullies. A remote trigger adjacent to the west end of Glacier NP resulted in a sz 3.5 running from the Alpine to valley bottom.
Snow melt and rain has soaked the upper snowpack making it weak and easy to trigger.
A sun crust (Jan 3), down 60-80cm, can be found at and below Tree-line on S-SW aspects. Recent avalanches have been stepping down to this layer and deeper within confined gullies.
The Dec 1 surface hoar layer, down ~120cm, is decomposing.
Warm air from the south west will maintain elevated freezing levels and high temperatures for the next several days. Gradual cooling will begin on Friday.
Wed: Mix of sun and cloud. High 2°C. Light gusting moderate SE winds. Freezing level (FZL) 2600m.
Thurs: Cloudy with isolated showers or flurries. High 0°C. Winds S light. FZL 2200m.
Fri: Cloudy with isolated flurries. High 1°C. FZL 2000m.
