Avalanche Forecast

High -

Tuesday: Cloudy with light flurries beginning in the afternoon and bringing 3-5 cm of new snow by Wednesday morning. Light to moderate southwest winds, strong in the alpine. Freezing level returning to valley bottom with alpine high temperatures of -2 and dropping as the temperature inversion breaks down. Wednesday: Mainly cloudy with lingering flurries and a trace of new snow. Light to moderate northwest winds. Alpine high temperatures of -9, closer to -4 in the south of the region.Thursday: A mix of sun and cloud with cloud increasing and bringing light flurries and a trace of new snow, continuing overnight. Light to moderate southwest winds, increasing overnight. Alpine high temperatures of -10, closer to -5 in the south of the region.

Reports from Sunday included observations of numerous small wind slabs releasing with skier traffic and ski cutting on steep treeline and alpine features in the north of the region. This was after a bout of intense wind loading from strong to extreme northerly winds. One natural size 2.5 wind slab release was also observed on a southeast aspect.On Saturday, skiers triggered a size 2 wind slab on a north east aspect near 2000m in the Duffey zone. See the MIN report for more details. Friday there were isolated reports of natural cornice triggered and wind slab activity up to size 2.5, as well as evidence of an older large, natural size 3.5, in high alpine terrain in the Duffey Lake area.On Thursday, the southern part of the region reported a natural slab avalanche size 3.5 from a NE-SE aspect near 1800 m and numerous wet slabs up to size 2.5. An avalanche control mission using explosives in the northern part of the region saw wind slab results up to size 1.5, only running in the surface snow and not stepping down deeper.

Snowfall totals from last week are highly variable. In the south, up to 40 cm of new snow fell and brought alpine totals up to 60 cm for the storm ending last week. In the north, new snow totals are about half that and rapidly decrease below 1800m. This new snow remains unconsolidated in wind-sheltered, shaded areas at upper elevations but strong northerly winds have scoured windward ridge crests and formed wind slabs in open areas at treeline and above.Below the snow surface, 80-150 cm down in the mid snowpack sits the mid-January crust. It generally shows signs of bonding to the overlying snow; however, I would remain suspect of this deeper layer while the snowpack adjusts to the new load. Thinner snowpack areas may have a higher likelihood of an avalanche failing on this layer. Large, looming cornices exist, they are fragile and demand respect. Cornice falls are very effective triggers for avalanches on the slopes below them.At lower elevations, travel is rugged and some are recommending ski crampons below treeline.