Avalanche Forecast

A couple more weak short waves and weak bands of precipitation should move out of a large weak trough and over the Northwest on Tuesday. This will cause more periods of mostly light snow in the Olympics and Cascades on Tuesday. A slight warming trend should be seen on Tuesday.

This weather will continue to allow 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. 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.

New snowfall may start to bury or further bury possible surface hoar and near surface faceted snow from around New Years. This new snow may continue to be somewhat upside down with denser snow near the surface which contributes to instability. These layers could be reactive where new accumulations become more than a few inches. This should be most likely in the central east and southeast parts. 

Fair weather was seen the last couple days of December through the weekend. This weather caused lots of consolidation and stabilizing of the snow from December. It also caused new widespread surface hoar and near surface faceted snow along the east slopes.

Tom Curtis was west of Blewett Pass around Iron Mountain New Years Day 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 North Cascades Mountain Guides on January 1st and 2nd at Washington Pass generally report good stable conditions and a lack of results in snow pit tests. Minor wind effects have been noted near ridges.

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.

A change Sunday night and Monday has been some snow and a warming trend. Snowfall has ranged from about 1-8 inches along the east slopes mainly in the central to south parts.

This new snow will be upside down with denser snow near the surface and may have accumulated on surface hoar and near surface faceted snow from around New Years.