Touchy slabs are being triggered by skiers. Don't let the blue skies influence your decision to attack the big lines.
Weather Forecast
The high pressure ridge will hold strong over the Columbias for the next few days. Alpine highs will slowly sink to -20*C or lower by the weekend, with light northerly ridge-top winds, and no snow in the near future.
Snowpack Summary
30-40 cm of storm snow is over the November 28 surface hoar/crust interface. The November 12 surface hoar layer is down 60-110cm.
Avalanche Summary
A large size 3 was observed off a N aspect on Cheops, as well as several size 2 avalanches from SSE aspects in 8812 Bowl. Several size 2 to 2.5 avalanches throughout the highway corridor yesterday, including a size 2.5 from Moccasin Flats that showed good propagation. All appeared to be 30-40cm deep, likely on the Nov 28 surface hoar/crust.
Confidence
Due to the number and quality of field observations
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.