There is uncertainty with snowfall amounts Monday night through Tuesday. Avalanche danger is expected to rise as snow accumulates through the day on Tuesday.
Snow accumulating overnight Monday and through the day Tuesday combined with moderate southwest wind will promote storm slab formation. Expect slabs to become more reactive through the day. The new snow has also obscured widespread windslabs (including open areas below treeline) that formed over the weekend.
Monday Night: Snow, accumulation 10-20 cm. Light to moderate west winds. Alpine temperatures around -5 C. Freezing level 700 m
Tuesday: Snow, accumulation 20-30 cm with another 15-25 cm through Tuesday night. Moderate southwest winds. Alpine temperatures around -3 C. Freezing level 1300 m.
Wednesday: Scattered flurries, accumulation 5-10 cm. Moderate southwest winds. Alpine temperatures around -3 C, freezing level 1200 m.
Thursday: Mainly cloudy. Light northwest winds. Alpine temperatures around -10 C. Freezing level valley bottom.
Expect to see an increase in storm slab activity as the wind picks up and new snow accumulates on Tuesday.
This MIN from Harvey on Saturday includes a photo of a size 1 wind slab avalanche in the lee of a ridge feature below treeline, and describes signs of instability like shooting cracks.
20-30 cm of new snow has now obscured widespread wind affected snow that extended well below tree line. Recent Cornice growth in the alpine has been notable.
Several crusts layers have formed in the mid to upper snowpack as a result of recent warming and rain events. As these crusts become buried deeper, they have the potential to turn into a persistent slab problem. We'll be keeping an eye on them going forward.
The lower snowpack consists of weak faceted snow and decomposing crusts but has not been an active avalanche problem recently.
