Avalanche Forecast

Fair

Thursday: Arctic air surges south giving colder and drier weather. Expect a mix of sun and cloud with increasing cloud later in the day. Alpine temperatures should be around -15 to -20. Winds are light to moderate from the northwest-west. Friday: Light snow should begin Thursday night with around 5 cm expected through Friday. The freezing level is at valley bottom and winds are moderate from the west-southwest. Saturday: Lingering flurries in the morning, then clearing. The freezing level is at valley bottom and winds are light from the northwest.

There were no new reports of natural avalanches on Tuesday. On Monday several natural slab and skier controlled avalanches up to size 2 were reported. 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 and both cracking and whumpfing have been observed.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.