Avalanche Forecast

High -

Wednesday night: Clear with cloudy periods. Light northeast winds increasing to moderate in the alpine.Thursday: A mix of sun and low elevation cloud. Moderate northeast winds decreasing to light. Alpine high temperatures around -8Friday: Cloudy with increasing flurries bringing 2-5 cm of new snow by end of day, continuing overnight. Light east or southeast winds increasing to moderate. Alpine high temperatures around -4.Saturday: Cloudy with continuing flurries bringing 5-10 cm of new snow and new snow totals to 15-20 cm. Flurries continuing overnight. Strong to extreme south winds. Alpine high temperatures around -4.

Storm slab avalanches up to size 3 continued to be reported into Sunday after the warm and wet storm that hit the region at the end of the week. Storm and wind slabs are likely gaining strength, but will take longer to stabilize on slopes facing the sun and where wind effect is more pronounced. An avalanche incident was reported in the Shames backcountry area last Thursday. The incident involved two skier triggered avalanches occurring in succession with two people involved and partially buried. The details can be found on the Mountain Information Network. (here) A very large (size 3.5) natural avalanche occurred in the north of the region on Sunday that is believed to have initiated on a buried layer of surface hoar then stepped down to the weak layer from early December. A few other large avalanches from the storm are suspected to have 'stepped down' to the late Novermber crust/facet combination at the base of the snowpack.

A warm and wet storm brought up to 100 mm precipitation between Wednesday and Sunday last week, with rain falling as high as 1500 m. Forecast outflow winds, although mainly expected at lower elevations, may be blowing the new snow into new wind slab deposits at higher elevations. The snow is crusty at lower elevations, with little snow available to be transported by the wind.In some sheltered areas that were unaffected by rain, the new snow is sitting on a weak layer of surface hoar (feathery crystals). For most of the region, a weak layer of facets (sugary snow) buried in early December exists down 180-250 cm. The likelihood of triggering this layer is decreasing, but it could be triggered by humans in shallow snowpack areas, particularly in the north of the region. The potential may also exist for storm slab avalanches to step down to this layer, resulting in large avalanches. A combined crust/facet layer may also be found at the base of the snowpack in alpine areas. It is suspected to have been involved in several large 'step down' avalanches during the storm.