A winter storm entered the area Thursday night that is predicted to bring 8-16" of snow and shifting winds into the area through Saturday morning. New snowfall will build thin storm slabs today, slabs will gradually become thicker and more likely to cause avalanches by Saturday. Winds will shift and become stronger as the storm progresses, this will load terrain near ridgelines and in steep gullies on all aspects. Pay attention to signs of slab development at your location, particularly on east aspects where the wind may be loading steep terrain today.
Storm snow has begun to fall in the mountains and will continue through Saturday morning. The new snow will be resting on a variety of crusts and wind scoured surfaces that my bond poorly with the new snow. Snow totals as of this morning were showing 3-4", with another 4-8" falling throughout the day and gusty winds out of the west.
Two issues exist here. There is a layer of buried surface hoar at Treeline and above on northeast aspects that is unlikely to be triggered at this time. The second issue is the crust layers in the upper snowpack that are layered with weak, sugary snow. These surfaces were not a concern yesterday, but as we load them and build a fresh slab above them they will become a "tomorrow" kind of problem.
On Thursday Nate and I toured into the Keeler Creek area. We found stable conditions on all aspects, the most important observation of note is the wide array of surface conditions out there. On any given aspect there is some combination of crust layers that are sandwiched with facets. This set-up will give us a poor surface for the storm slab to bond with and may be a problem for awhile. I see this as our next "persistant slab" setting up, time will tell how persistent it may be.
The big story right now is the incoming weather. Yesterday's stable conditions will deteriorate and avalanches will become more likely and larger in size as the storm progresses. Overnight the west/southwesterly winds will switch to northwest and then more easterly by Saturday. This will cause wind loading on most aspects by Saturday and create slabs in terrain that is not sheltered by timber. Pay attention to the surface conditions today, slabby snow and shooting cracks will be signs that you need to stick with mellow terrain. You may be able to get away with steeper slopes early in the day, by afternoon you will want to dial it back a notch.
