Avalanche Forecast

Moderate - Intensity of incoming weather systems is uncertain

SUNDAY: Cloudy with light flurries, accumulation 5 to 15 cm, light southwesterly winds building to strong over the day, alpine temperature near -8 C, freezing level near valley bottom.MONDAY: Cloudy with light flurries, accumulation 5-10 cm, light southwesterly winds, alpine temperature near -6 C, freezing level near 1000 m.TUESDAY: Cloudy with light flurries, accumulation 10-15 cm, light to moderate southerly winds, alpine temperature dropping to -12 C over the day, freezing level near valley bottom.

Numerous small loose avalanches have been reported in the region over the past few days.  Slab avalanches are becoming more likely with new snowfall, as the upper snowpack settles.

10-20 cm of new snow fell on surface hoar in sheltered slopes and a sun crust on steep solar aspects and may not bond well to them.  The snow also may have fallen with moderate southwesterly winds in the alpine, which could have produced small wind slabs in lee features.The new snow could create a dangerous slab above buried weak layers.  Numerous persistent weak layers exist deeper in the snowpack.  Dry snow overlies two layers composed of weak and feathery surface hoar, with the deeper layer (December 15) buried 30 to 60 cm.  This layer is shallower in the north of the region and deeper in the south of the region.  The weak layer is found most often at treeline and below treeline.  If the dry snow above the weak layers becomes more cohesive and forms a slab, the setup has the potential to create easily-triggerable destructive slab avalanches.Deeper in the snowpack at depths of about 70 to 100 cm, a rain crust from November is producing variable snowpack test results, from sudden fracture characters to no result.  This layer is considered dormant for now, but could be triggered where the snowpack is thin.Please share your observations through the Mountain Information Network.