Watch for signs like shooting cracks showing you the new snow has consolidated into a reactive slab. Loose snow will present an additional risk in steeper terrain.
Weather Forecast
Sunday night: Flurries bringing approximately 10 cm of new snow. Winds light from the east.Monday: Cloudy with scattered flurries delivering 5-15 cm of new snow. Winds light from the southwest. Alpine temperatures of -15.Tuesday: A mix of sun and cloud with isolated flurries and a trace of new snow. Winds light from the southwest. Alpine temperatures of -13Wednesday: Cloudy with sunny periods. Winds light from the light gusting to moderate from the southeast. Alpine temperatures of -9.
Avalanche Summary
Reports from Saturday include numerous Size 1-2 storm slabs being triggered both naturally and with ski cutting, as well as with explosives control. These soft slab avalanches have been noted as very reactive to skier traffic, fast-running, and capable of entraining large amounts of loose snow.As for Monday's outlook, fresh storm slabs are continuing to build and should be expected to be sensitive to light triggers, especially where they overlie weak layers present at our previous surface and where exposure to wind has promoted slab formation. Loose snow avalanches are also beginning to evolve into something more than a 'good skiing problem' and should not be underestimated in terrain where they have the potential to entrain significant mass.
Snowpack Summary
20-30 cm of new snow over Friday and Saturday has now buried a range of different conditions that existed at our previous surface. In addition to wind slabs that exist on a variety of aspects in exposed terrain, the new snow also overlies a sun crust recently reported on steep solar aspects as well as surface hoar recently found growing on sheltered open slopes. Surface faceting has also been reported as a result of last week's cold temperatures. The bond of the new snow to these underlying surfaces will likely be weak and touchy conditions can be expected as the new snow continues to accumulate into storm slabs above them. A persistent weakness buried mid January is now down 40-70 cm and consists of buried surface hoar in sheltered areas, sun crust on south aspects, and/or widespread faceted old snow. It has generally stabilized but may be sensitive to triggering in isolated areas where buried surface hoar is preserved. The mid and lower snowpack are generally well settled and stable.
Problems
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.