Wed, Dec 30, 2020 - 1:00 PM
Three Sisters Area
Ski or Snowboard
I toured up to the summit of Tumalo. On the way up the west side the wind picked up from light (1-16 mph) to moderate (17-25 mph). The wind shifted from S to SW. There was approximately 5 cm (2") of new snow at around 11:00am.
Blowing snow was observed as the trees thinned out. On the summit (7775 ft), blowing snow was observed moving into the bowl and over to the north side of Tumalo. I skied into the far skier's left side of the bowl. I observed cracking in recently formed wind slab (see picture). Several very small wind slabs released; crowns were up to 8 cm. These were very small, but a sign that wind loading is occurring and wind slabs are building. New wind slabs will be something to watch for on lee slopes near and above treeline.
I exited the bowl and skied onto the north side of the mountain and dug into the snow to check out the layering in the upper and mid pack (full profile below). I found several crust/weaker snow sandwiches below the 12/22 rain crust, down about 30 cm. It is unlikely avalanches will initiate on these layers, but they will be something the COAC observers will keep an eye on. Aside from the crust/rounding facet combos, the snowpack is showing good structure.
Ski quality was excellent in the trees.