Triggering storm slab avalanches will become more likely as snow accumulates throughout the day.
Several persistent weak layers are buried in the snowpack and may still possible for humans to trigger on isolated slopes.
New snow, wind, and mild temperatures will form reactive storm slabs, especially at higher elevations and wind affected terrain.
WEDNESDAY NIGHT: Cloudy and light flurries, moderate wind from the southwest, alpine temperatures drop to -5 C.
THURSDAY: Flurries increasing intensity throughout the day with 10-20 cm of new snow, moderate wind from the southwest, freezing level up to 1500 m with alpine high temperatures around -2 C.
FRIDAY: Scattered flurries with 5-10 cm of snow, light to moderate wind from the southwest, freezing level around 1500 m with alpine high temperatures around -2 C.
SATURDAY: Cloudy with light flurries, light wind from the southwest, freezing level around 1500 m with alpine high temperatures around -2 C.
The incoming storm will form fresh slabs at higher elevations. Between Monday and Wednesday there have been a few reports of small (size 1) skier triggered avalanches in steep terrain and larger (size 2) explosive triggered storm slab avalanches on all aspects at treeline elevations. No persistent slab avalanches have been observed in the past week, suggesting they are becoming less likely to trigger.
Another 10-20 cm of new snow on Thursday will bring a total of 15-30 cm of snow above a thin crust layer that formed on Monday. Strong wind from a variety of directions has created variable surface conditions in open terrain.
There are two layers of surface hoar found around 70 to 130 cm below the snow surface that have been an issue in steep, sheltered, and shallow rocky areas. The base of the snowpack in many parts of the region consists of weak faceted crystals and crusts. Recent observations suggest these persistent weak layers are becoming less reactive.
