Steady snowfall and elevated winds are building wind slabs in exposed areas. Seek out sheltered lower elevations free of overhead hazard. There's a definite chance of wind slab releases triggering a deeper snowpack layer to create larger, more destructive avalanches.
New snow and ongoing southwest winds will likely be forming new wind slabs on north and east aspects through Tuesday. New slabs that form aren't expected to bond well to the underlying surfaces.
Avoid steep rocky slopes near ridge crests where these slabs might be capable of stepping down to deeper layers.
Buried weak layers have recently produced large, surprising avalanches. These layers will be easier to trigger where the snowpack is thin.
The most recent avalanche activity has been observed on north to northeast alpine terrain on preserved surface hoar buried 50-80 cm. Keep in mind the potential for remotely triggered avalanches and that large avalanches can run far into flatter terrain. Stiff slabs can also pull back into flatter terrain above them.
This MIN discusses new wind slab formation. We expect wind slabs to increase in size and reactivity.
A couple of large (size 2-3) persistent slab, human-triggered and natural avalanches were reported last week. These avalanches occurred near ridgetops in north-to-northeast alpine terrain. These avalanches have shown an impressive capability to propagate across large distances. Here is a link to the most recent human-triggered size 3 avalanche.
If you are out in the backcountry please consider filling out a Mountain Information Network report.
New snow continues to accumulate with southwest winds forming wind slabs on north and east aspects. New snow is resting on a variety of wind-affected surfaces and crusts with small surface hoar in places in the alpine. Below roughly 1700 m a widespread 5-10cm melt-freeze crust is present at or near the surface.
A concerning persistent weak layer of surface hoar and/or facets is 50-80 cm deep and exists on north facing alpine features.
Check out this MIN from our field team to learn more.
Monday night
Cloudy with flurries bringing 5-10 cm of new snow. Strong southwest winds.
Tuesday
Mostly cloudy with continuing flurries bringing about 5 cm of new snow. Moderate to strong south winds. Treeline high temperatures around -7.
Wednesday
A mix of sun and cloud with flurries bringing less than 5 cm of new snow. Light to moderate southwest winds. Treeline high temperatures around -8.
Thursday
Cloudy with isolated flurries and a trace of new snow. Light northeast winds. Treeline high temperatures around -10.
More details can be found in the Mountain Weather Forecast.
