Avalanche Forecast

Partly cloudy to mostly sunny weather with cool temperatures and light winds are expected Wednesday. This should allow for recent wind slabs to continue to slowly settle and stabilize.

Wind slab will most likely be found on north to southeast aspects near and above tree line, except locally on southwest-northwest aspects near the Cascade Passes.  Any wind slab avalanches should be confined to shallow near surface layers. Test for inverted strong over weak storm snow and give cornices a wide margin.

As the deep recent snow continues to gradually settle, loose dry slides should be less likely, however watch for sun breaks affecting steep S facing slopes as this may rapidly consolidate surface snow and allow for propagation of shallow slab releases or some natural loose wet slides which may trigger slab releases, such as seen in the Mt Baker area Monday.

There have been snow immersion fatalities in tree wells already this season at Snoqualmie and in Canada. Recent unconsolidated storm snow is still very deep in places with possible large tree wells lurking, so stick near your partner in the trees and maintain visual contact.  

For the week ending on Dec. 24th, a snowy and cool storm cycle brought 5-9 feet of snowfall along the west slopes. Only light additional accumulations over the last five days have allowed the snowpack to slowly settle, with generally still very good skiing and riding!

With that said, there have been numerous triggered wind slabs ranging from the Mt Baker to Snoqualmie Pass areas, Sunday through Tuesday. With each passing day the extent of wind slab and ease of trigger is diminishing.

With all the great new snow, there have been a great deal of observations and most are telling a similar story. The storm slabs have all but settled and are no longer a problem of note. The recent wind slabs are becoming less extensive, more difficult to trigger, and now mainly confined to specific terrain features or just below ridges near or above treeline. The storm snow is gradually settling but remains mostly right side up and continues to offer some excellent touring conditions!

Tuesday the 29th, NWAC observer Ian Nicholson traveled in the Alpental Valley in the Commonwealth Basin area to Red Mountain and found similar conditions to those stated recently. The wind slabs, formed Sunday during snowfall and a period of moderate east winds in that area, were confined to near ridges and ranged from about 10-30 cm and where triggered, remained small (D1). Otherwise a settling, right side up snowpack was observed with the December 9 crust between 150-170cm below the surface with no significant weaknesses noted in tests.

Monday the 28th, NWAC observer Lee Lazzara in the Mt Baker area, traveled above Bagley Lakes towards Mt Hermann and during a late morning sun break observed a loose wet natural release from the S slopes of Mt Hermann that triggered a slab release that ran a fair distance. There was evidence of another ski triggered wind slab from Monday as well, on a steep SSW facing slope. These wind slab deposits were evident in a variety of aspects from recent wind redistribution. While there are plenty of great snow conditions, it is still prudent to remain cautious of large unsupported features and avoid large slopes with big consequences.

Jeff Ward traveled in the Stevens Pass area Monday to near tree line. In that area, only small, isolated wind transport was noted, mainly to some exposed W facing slopes below ridges where the shallow wind stiffened snow overlaid weaker snow. In this area, no avalanches were noted and the snowpack was gaining strength and remained with a good profile of gradually increasing density, providing excellent ski quality, however no observations were made above tree line.   

Alpental pro-patrol did observe local east winds at Snoqualmie Pass Sunday and report wind loading built thin wind slabs over weaker snow near treeline Sunday.