A few cm of snow over the next few days will give the winds something to transport for the first time in a while. A conservative approach to terrain selection remains important with the existing weak snowpack structure.
Weather Forecast
NW flow to the upper atmosphere brings unsettled cool air to the region through Thursday.Tues: Cloudy with flurries (up to 5cm of snowfall). Alpine Low -16 C, High -12 C. Ridge wind light West (gusting strong)Wed: Cloudy with sunny periods and isolated flurries. Alp Low -15 C, High -12 C. Ridge wind light SW (gusting moderate)Thurs: Up to 10cm snow
Snowpack Summary
Old wind slabs and extensive wind effect found in open areas. The upper snowpack has settled to form a 50 to 80 cm slab that sits on three weak layers in the mid-pack which can be found throughout the forecast region, and produced many large avalanches during the Feb 8th cycle. The entire snowpack is faceting after two weeks of cold, dry weather.
Avalanche Summary
Helicopter patrol down highway 93 Sunday night noticed only a few recent windslabs in the alpine. There has been limited activity over that last two weeks following the extensive avalanche cycle on February 8-9 yet it is still prudent to treat slopes that did not avalanche during this cycle with a great deal of respect.
Confidence
Intensity of incoming weather systems is uncertain on Monday
Problems
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
Wind Slabs
Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.