Variable distribution of wind slab in the alpine and buried surface hoar layers at tree line and below demand your attention. Choose low consequence terrain, human triggered avalanches are possible.
Weather Forecast
Cold and cloudy with little chance of seeing the sun makes me want to stay inside today... but I won't. Alpine high of -16 with isolated flurries (~2cm for the day) and light ridge top winds from the South West. Friday will be similar to today, cold temps and clear skies for the weekend.
Snowpack Summary
A thin sun crust has formed on steep solar aspects in alpine. Cold temps promoting near surface faceting and softening wind slabs that exist in alpine and exposed areas at tree line. The storm snow has settled has to ~50cm. The Jan 31 and Jan 17 interfaces (surface hoar and sun crust) are down ~50cm and ~70cm at tree line.
Avalanche Summary
A skier triggered size 2.0 yesterday from steep, exposed terrain on Glacier Crest as well as a natural cornice triggered size 2.0 in 'Rail Road Gunners'. There was a large natural cycle over the weekend with many slides running full path.
Confidence
Due to the quality of field observations
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.