Confidence
Poor - Track of incoming weather is uncertain on Wednesday
Weather Forecast
Tuesday: Continued light flurries with treeline temperatures in the minus teens and strong westerly alpine winds.There is high uncertainty with the weather for Wednesday and into Thursday. Some forecast models are calling for light to moderate snowfall with associated winds, while others are calling for dry and mostly clear. It all has to do with the track of a frontal system that's primarily heading south of the region. If heavy loading from snow or wind does occur, then expect avalanche danger to increase.
Avalanche Summary
Reports from yesterday include a few reluctant slope cut Size 1 soft slabs on steep, convex, unsupported features. They had limited propagation and did not run far. Slope cuts on steep north facing convexities also triggered isolated stubborn buried wind slabs down 60cm with avalanches up to Size 1. Low density storm snow is sluffing readily in steep terrain with a natural cycle overnight Saturday. In some cases they're entraining considerable mass and reaching up to Size 2.
Snowpack Summary
20-40 cm of low density new snow is being redistributed by westerly winds forming weak wind slabs and cornice tabs on lee aspects, but remains fluffy and cohesionless in most sheltered areas. This new snow now sits on a variety of surfaces (facets, surface hoar in sheltered areas, soft slabs, hard slabs, wind crust, and a melt-freeze crust below treeline), and currently seems to bonding poorest to underlying crusts. Although still well preserved in isolated areas and producing hard but sudden snowpack test results, avalanche professionals are gaining confidence in the mid-December persistent weakness, now down 110-190cm. The probability is very low (it would take large triggers in the perfect spot) but the consequences would be very high.
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.
Loose Dry
Loose Dry avalanches are the release of dry unconsolidated snow and typically occur within layers of soft snow near the surface of the snowpack. These avalanches start at a point and entrain snow as they move downhill, forming a fan-shaped avalanche. Other names for loose-dry avalanches include point-release avalanches or sluffs.