Avalanche Forecast

The recent clear weather has given way to increasing clouds and a return to a few light showers late Sunday that should continue into Monday. The areas near the crest, east of the passes and approaches to the passes will remain cool. Light snowfall may bury recently formed surface hoar or near surface faceted snow. This may become a future problem layer.

This weather will continue to allow the older wind slab to slowly settle and stabilize. Wind slab will most likely be found on north to southeast aspects near and above tree line. Any wind slab avalanches should be confined to surface layers and cool temperatures east of the crest will slow the stabilizing of these layers. East winds were much lighter east of the crest since Thursday and will likely not have built new wind slab on westerly aspects. Watch and test for inverted strong over weak storm snow.

Watch for the buried surface hoar layer found recently west of Blewett Pass by two independent recent observations buried between 45-60 cm. 

A cool and snowy storm cycle brought 2-4 feet of snowfall to the east slopes the week ending December 24th. Light additional accumulations over the past week have allowed the snowpack to slowly settle and good skiing and riding conditions have been reported in non-wind affected terrain, though these areas are becoming more scarce with passing days.

Recently, separate observations from NWAC observer Tom Curtis in the Blewett Pass backcountry, the Icicle Canyon area, as well as North Cascades Mountain Guides report generally a right-side up snowpack in non-wind affected terrain. Widespread surface hoar has been forming over the past several days and is being reported throughout the range along the east slopes. This layer,  or weak near surface faceted snow that has also been reported, may be buried late Sunday or Monday by expected light snowfall.

Isolated pockets of wind slab are still thought to exist in the above treeline zone. Loose dry avalanches are still possible on steeper slopes, whether potentially triggered by skiers or on solar slopes by sunshine.

Tom Curtis was west of Blewett Pass around Iron Mountain Friday and found the December 13 buried surface hoar layer 60 cm down that showed sudden collapses in several column tests, including PST with a firm slab overhead. In this area, the layer was prevalent on NE-E aspects around 5300 ft near treeline. This layer was also noted in a recent observation posted to NWAC.  There were no recent skier or natural triggered avalanches on this layer, but it may be a layer of concern to track or look for moving forward in this specific area. 

PST End down, 60cm on 20151213 buried surface hoar layer. West of Blewett Pass, January 1, 2016. ENE aspect NTL @ 5330ft. Photo: T. Curtis 

The southeast zone has a shallower snowpack versus areas further north, but after a snowy few weeks, has more than enough snow to warrant an avalanche risk. No snowpack observations have been received from this zone.