Don't let the lack of natural avalanche activity fool you today. Sunny skies may lure you to the big lines - but the Feb. 12 PWL is unpredictable, and tests indicate that it is very reactive in many locations. Watch for solar warming and cornices.
Weather Forecast
A ridge of high pressure will remain over the region bringing clear skies and dry conditions. Winds will remain light from the SW, with mild temperatures. Another frontal system will move in on Thursday, bringing cloud and light flurries. The main impulse of the next system will arrive on Friday, for the weekend.
Snowpack Summary
Hard and Soft slabs overly a weak layer of surface hoar, now buried 50-60cm.� This surface hoar is best preserved and reactive between 17-1900m, and is most reactive on solar aspects where it rests on a buried sun crust.� RB scores of 2 (whole block), and wide avalanche propagations confirm that this layer is becoming more reactive as it matures.
Avalanche Summary
Natural avalanche activity is tapering off in the park, however skiers are still able to pop out slabs in the backcountry. It seems that the weak layer we are tracking now requires a specific trigger, such as a cornice fall, a skier, or even a tree bomb.
Confidence
Due to the number 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.