Change is in the air, but alpine winds will be leading the charge in this week's series of storms.
Weather Forecast
Sunday night: Cloudy with scattered flurries bringing a trace to 3 cm of new snow. Light south winds, increasing to strong southwest in the alpine.Monday: Mainly cloudy with isolated flurries and a trace of new snow. Light to moderate southwest or west winds. Alpine high temperatures around -8.Tuesday: Cloudy with scattered flurries and 2-4 cm of new snow, increasing a bit overnight. Mainly light southwest winds, increasing to strong or even extreme in the alpine and increasing further overnight. Alpine high temperatures around -7Wednesday: A mix of sun and cloud with easing flurries and a trace of new snow. Strong northwest winds increasing to extreme in the alpine. Alpine high temperatures around -9.
Avalanche Summary
Several size 1.5 natural wind slab avalanches were reported from a steep south through southwest facing alpine feature on Friday.
Snowpack Summary
Recent moderate winds have created wind slabs in the alpine and isolated treeline areas.There are two layers of surface hoar (weak feathery crystals) being reported in the top 15-30cm. The surface hoar is most prominent at treeline, but it may be found in sheltered alpine areas. Both of these layers may be associated with a sun crust on south aspects in some areas.Another major feature in the snowpack is a combination of a crust and faceted (sugary) snow found at or near the base of the snowpack. This layer is most prominent in the alpine.The early season snowpack is highly variable in the Purcells. Total snowpack depths vary greatly throughout the region with anywhere between 70 and 150 cm in the alpine tapering rapidly at treeline and below. In shallow snowpack areas, the bottom half of the snowpack is reportedly weak and "hollow" feeling on shady aspects due to sugary, faceted snow.
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.