Recent wind loading of storm snow over the November 11th surface hoar layer requires skiers and riders to have a cautious approach to their route selection today.
Weather Forecast
Light S winds and another 20cm of snow expected today. Temperatures will remain close to zero during the day with a cooling trend overnight tonight. Monday brings a small break between systems with another pulse of precipitation coming Monday night through Tuesday with upwards of 40cm of snow.
Snowpack Summary
20cm snow overnight with light winds will be enough to obscure the wind slabs formed on alpine lee features during Friday's storm. Yesterday allowed a view of alpine fetch stripped down to bare rock by Friday's strong S-SW winds. Lee features will be harboring slabs well down slope from ridge lines. Nov 11 surface hoar resides under the slabs.
Avalanche Summary
Limited observations of a few avalanches along the highway corridor out of steep lee slope terrain.
Confidence
Due to the number 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.
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-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.