Conditions are changing - strong winds and warm air aloft are creating new avalanche problems. Cornices and winds slabs could trigger deeper weak layers.
Weather Forecast
A ridge of high pressure will continue to maintain dry conditions. The inversion is expected to continue today, providing warm clearing skies at higher elevations, and cloud and cooler temperatures in the valleys. Winds will stay moderate to strong.
Snowpack Summary
Warm temperatures in the alpine (inversion) combined with moderate to strong SW winds are continuing to create hard and soft slabs, especially in the alpine. These slabs overlie the January 4 interface, down 40-60cm. Steep solar aspects are most reactive due to facets on a crust. Significant loading should also be expected on NE aspects.
Avalanche Summary
Most reported avalanches have occurred on S and W aspects in the alpine, and are associated with the January 4 sun crust. Pockets of wind slab have also been observed to fail in specific terrain, mostly on cross loaded features. Cornices are beginning to fail, causing avalanches to size 2.
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.