South Columbia

Fair

Wednesday: Cloudy with lingering flurries in the morning, gradually clearing and cooling throughout the day. The freezing level drops to valley bottom and winds are light to moderate from the northwest. Thursday: Mainly sunny with increasing cloud later in the day. Temperatures drop as Arctic air surges south. Winds are light to moderate from the northwest-west. Friday: Cloudy with flurries or light snow. The freezing level is at valley bottom and winds are moderate from the west-southwest.

Several natural slab and skier controlled avalanches up to size 2 were reported on Monday. Most of these were fresh wind slabs or storm slabs from northerly terrain. Explosives control also produced a number of very large avalanches (up to size 4) in the far northern end of the region. A couple of these were reported to have failed on the October crust near the base of the snowpack.

Strong westerly winds near ridgetop have created dense wind slabs in exposed lee terrain while scouring windward slopes. Mild temperatures have also promoted settlement and slab development. A weak layer of surface hoar, facetted snow, and/or a crust is now down 30-60 cm (deeper in northern sections). This layer has recently been reactive to riders and natural triggers. The late-November interface, which consists of a sun crust on steep south facing slopes and surface hoar in sheltered areas, is buried 60-90cm below the surface and is generally considered to be "stubborn" to trigger. At the base of the snowpack the October crust is lurking in specific terrain, like north-facing alpine slopes with smooth ground cover.