Avalanche Forecast

Moderate - Timing, track, or intensity of incoming weather system is uncertain

MONDAY: Mostly cloudy with intermittent snowfall, accumulation 2-5 cm, moderate to strong southwesterly winds, alpine temperature near -12 C, freezing level near 800 m.TUESDAY: Mostly cloudy with intermittent snowfall, accumulation 1-3 cm, moderate southerly winds, alpine temperature near -10 C, freezing level near 600 m.WEDNESDAY: Mostly cloudy with intermittent snowfall, accumulation 1-3 cm, moderate southerly winds, alpine temperature -7 C, freezing level near 500 m.

Many avalanches were reported on Saturday (with conditions indicated as Spicy).  Small to large (size 1 to 3) storm slabs and wind slabs were noted on Saturday, being triggered naturally, by skiers, snowmobiles, and explosives.  The avalanches released generally on lee slopes (northerly to easterly) at all elevation bands, ranging from 30 to 90 cm deep.  Many of the avalanches released on the persistent weak layers described in the Snowpack Summary.  Similar avalanches were observed on Thursday and Friday.

The current snowpack is complex, we now have three active weak layers that we are monitoring. 20-50 cm of storm snow sits on a newly formed crust and/or surface hoar layer (mid-January). Prior to the storm the crust was reportedly widespread; high elevation north is likely one of the few crust-free zones. The mid-January surface hoar is up to 10 mm and reported at all elevation bands. The new snow fell with strong southwesterly winds, producing wind slabs in lee features. Deeper in the snowpack, the early-January persistent weak layer is 30 to 70 cm below the surface. It is composed of surface hoar on sheltered slopes and sun crust on steep solar aspects and found at all elevation bands. Snowpack tests show sudden fracture characters with moderate loads and high propagation potential, as well as whumpfs and cracking. Another weak layer buried mid-December consisting of a facet/surface hoar/crust combination is buried 40 to 100 cm deep. It is most problematic at and below tree line.A rain crust buried in November is 100 to 150 cm deep and is likely dormant for the time being.