Avalanche Forecast

Moderate - Intensity of incoming weather systems is uncertain

TUESDAY: Cloudy with light snowfall, accumulation 5-15 cm, light to moderate westerly winds, alpine temperature near -8 C, freezing level near 1200 m.WEDNESDAY: Partly cloudy with intermittent flurries, light to moderate westerly winds, alpine temperature near -14 C, freezing level below valley bottom.THURSDAY: Cloudy with snowfall, accumulation 5-10 cm, moderate southwesterly winds, alpine temperature near -10 C, freezing level below valley bottom.

A slab avalanche was noted in a lee feature in alpine terrain within the recent storm snow, about 15 cm deep.Numerous signs of instability have been noted in the snowpack over the past week, including whumpfing and cracking between 1700 and 2100 m, and two skier-triggered avalanches suspected to have released on the December 15 weak layer.  Expect the potential to trigger persistent slabs to increase as the snow continues to settle into a cohesive slab.Please share your recent observations through the Mountain Information Network.

10-20 cm of new snow is forming a storm slab and sitting on surface hoar in sheltered slopes and a sun crust on steep solar aspects.  The snow fell with moderate to strong southwesterly winds in the alpine, which produced wind slabs in lee features at treeline and alpine elevations.  Below treeline, this new snow is mainly a concern in openings (e.g. cut blocks, gullies, cut banks).A warming trend and new snow is likely creating a dangerous slab above buried weak layers.  Dry snow overlies layers of weak and feathery surface hoar, with the deeper layer (December 15) buried 40 to 80 cm.  This layer is found most often around and below treeline but has been reported as high as 2450 m and could exist higher.  As the overlying dry snow becomes more cohesive and forms a slab, this layer has the potential to create easily-triggerable destructive slab avalanches.  This has occurred in neighbouring forecasting regions with a similar snowpack.Deeper in the snowpack (70 to 110 cm), a November crust is producing variable snowpack test results, from sudden fracture characters to no result.  This layer is considered dormant but could be triggered where the snowpack is thin.