Avalanche Forecast

Moderate - Forecast snowfall amounts are uncertain

Wednesday night: Scattered flurries bringing 2-4 cm of new snow. Strong to extreme southwest winds.Thursday: Cloudy with continuing flurries bringing 5-7 cm of new snow. Strong to extreme southwest winds. Freezing level to 1700 metres with alpine high temperatures around -2.Friday: A mix of sun and cloud. Moderate to strong southwest winds. Freezing level returning to near surface with alpine high temperatures of -6.Saturday: Mainly cloudy. Moderate west winds. Alpine high temperatures of -7.

Large persistent slab avalanches were observed north of Sparwood (see the report here), which likely occurred over the weekend. Otherwise, limited reports suggest wet loose avalanches have been running in steep solar terrain and small thin wind slabs (size 1-1.5) releasing in alpine terrain.

Light new snow amounts forecast for Wednesday night will begin to cover both a new layer of feathery surface hoar that has been developing in sheltered areas as well as sun crust on solar aspects. Recent warm temperatures formed this crust and also worked to settled the upper snowpack. Strong winds from the past few days have scoured windward slopes and formed new wind slabs in lee terrain at higher elevations. Wind direction has been variable but predominantly from the southwest.An unstable weak layer from mid-December (predominantly feathery surface hoar crystals and/or a sun crust) is found at treeline and below treeline elevations. Slabs can fail easily on this layer, either naturally or with the weight of a person or machine. Deeper in the snowpack, an early-season rain crust and sugary facets exist. An avalanche in motion could step down to these deeper layers, creating a large and destructive avalanche. Although the snowpack structure is variable across the region, these persistent slab problems are generally widespread. Snowpack depths are across the region are similarly variable, but typically shallower in the east.