Regions
Northwest Inland.
Recent observations are very limited from the region. If you're out in the mountains please consider sharing your observations on the Mountain Information Network.
Confidence
Low - Due to the number of field observations
Weather Forecast
Sunday: Mainly cloudy. The freezing level is at valley bottom and winds are moderate from the southeast. Monday: Cloudy with light snow – around 5 cm. The freezing level could rise to 600-800 m and winds increase to strong from the S-SW. Tuesday: Periods of snow. The freezing level rises to 1000-1200 m. Winds remain strong from the southwest.
Avalanche Summary
There are very few observations from the region. A couple natural size 2 slab avalanches were observed in wind-loaded terrain (N-NE aspects) at around 1800 m on Friday.
Snowpack Summary
Light snowfall with moderate southeast winds may be enough to form fresh, reactive wind slabs in lee features. In some places this could also activate buried surface hoar in the upper snowpack, generally found between 30 and 60 cm deep. Stay tuned to signs of instability like recent avalanches, whumpfing, and shooting cracks. The mid pack that was reported to be well settled may have now facetted in the shallower areas, and the deeper basal layers are almost certainly facetted and weak. We have not heard of any full depth releases on weak basal layers yet.
Problems
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.
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.