Human triggered avalanches remain possible, especially in wind loaded areas and at lower elevations where buried surface hoar layers exist.
Weather Forecast
THURSDAY NIGHT - Cloudy with scattered flurries, 5-10 cm / southwest winds 10-20 km/h / alpine low temperature near -13FRIDAY - Mainly cloudy with isolated flurries, 5 cm / east winds 10-20 km/h / alpine high temperature near -13SATURDAY - Mainly sunny / east winds 10-15 km/h / alpine high temperature near -21SUNDAY - Sunny / northeast winds, 10-20 km/h / alpine high temperature near -15
Avalanche Summary
A few natural wind slab avalanches size 1.5-2 on northwest aspects were reported on Wednesday.On Monday, size 1 natural and human triggered wind slab avalanches were reported on all aspects at treeline and in the alpine. On Saturday, numerous natural and explosives triggered storm slab avalanches to size 2-2.5 were reported on north and east aspects in the alpine and treeline. These avalanches were 50-100 cm deep.
Snowpack Summary
10-20 cm of new snow sits on previous wind slabs at upper elevations. In sheltered areas and below treeline, the new snow sits on facets (sugary snow) surface hoar (feathery crystals) and a crust on south facing slopes.There are potentially three weak layers of surface hoar in the top 100 cm of the snowpack. One is down 30-50 cm, another is down 40-80 cm and the last one is down 80-110 cm. These layers are most prominent between 1600-1900 m.The lower portion of the snowpack is considered generally strong.
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.