Avalanche Forecast

High -

A strengthening ridge is pushing warmer and warmer air into BC's Interior and the amplitude of the wave is quite dramatic. The result is something that we're becoming all too familiar with this season, inversion. Cold air in the valleys and warm temperatures in the alpine are expected through at least Tuesday. An unruly low-pressure system approaching the coast Wednesday should shake up the snow globe once againSUNDAY: Broken cloud cover in the morning, clearing throughout the day, freezing level at valley bottom with above freezing temperatures between 1600 m and 3000 m, light variable wind, no snow expected. MONDAY: Scattered cloud, freezing level at valley bottom with above freezing temperatures between 1700 m and 3000 m, light south wind, no snow expected. TUESDAY: Increasing cloud cover, diminishing inversion, warmer temperatures should make it to valley bottom, moderate to strong south wind, no snow expected.

Widespread avalanche activity occurred Friday with numerous reports of slab avalanches failing naturally and reacting to human triggering. All aspects have been involved as avalanches to size 2 continue to run on the January 5th interface. On Thursday avalanche activity involved both storm slabs on the January 5th surface hoar and persistent slabs failing on the December 15th interface. Sizes ranged 1 to 3, with slabs 40 to 80 cm in depth on all aspects/elevations. Deeper releases on the December 15 layer have been focused around treeline and below. Some of the themes that are emerging from recent activity include accidental and remote triggering, 'step down' release types, releases on surprisingly low angle, supported terrain, and wide fracture propagations.

Recent storms have brought 50 to 70 cm of new snow to the region. This storm snow sits on surface hoar on sheltered slopes as well as sun crust on steep solar aspects. Numerous storm slab avalanches resulted as the new snow formed a slab before bonding to the surface. Moderate to strong southwest winds have accelerated this slab formation at higher elevations.As the new snow continues to consolidate, it progressively forms a dangerous slab above several persistent weak layers that exist in the snowpack. The first of these is the January 5th surface hoar down 50 to 70 cm below the surface. Recent snowpack tests and avalanche activity show high reactivity at this layer. Another surface hoar layer from late December is showing increased involvement in 'step down' releases in the region. This layer is found at similar depths, but just below the January 5 interface.Below these layers, the December 15 surface hoar is now buried 70 to 110 cm deep. This layer has been the failure plane in many recent destructive slab avalanches, with many of these 'stepping down' to this layer from shallower releases. Its reactivity has been most apparent at treeline and below.