Observation: Turnagain

Location: Eddies

Date:
Observer:
Route & General Observations

Normal route up Eddies, mostly skiing near the trees to avoid the wind.

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?No
Observer Comments

The first time I reached the upper ridgeline I noticed some small wind pockets had released naturally along the highest parts of the ridge and a larger one had come off the higher summit. All were small, D1 pockets and none ran very far, except for the one off of the higher summit. That one was D2 (~1' deep and 50' wide crown) and ran most of the length of the steep face. I got on the upper ridge around noon and think those pockets all released in the morning as they looked fresh and each lap after that the crowns were more and more filled in and harder to see. All were on N, NW or W aspects.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.
Weather

Temperature was 26 at the trailhead when I started, high teens up on the ridge above treeline, and 27 when I got back to the trailhead. There was a trace amount of new snow. The big thing today was wind. Wind was blowing very consistently all day out of the S/SW. Down lower, there was a consistent light wind when I first exited treeline into the meadow area of lower Eddies, but up on the ridge it was moderate. I could see sastrugi actively forming on some areas of the Eddies ridge, and saw spindrift coming off the upper Tincan ridgeline. The overall wind levels seemed to very gradually increase throughout my tour and the wind levels were gusting to moderate in the lower meadow when I left.

Snow surface

The snow surface was fairly variable with soft snow in wind sheltered areas, and a mix of various wind crusts and sastrugi elsewhere. The lower Eddies meadow started with soft snow on my first lap, had a thin, easy to ski through wind crust on my second lap, and was just starting to form pockets of breakable wind crust by my third lap. There were pockets of hollow, breakable wind crusts of various thicknesses up higher on the ridge.

Snowpack

It was clear that the wind was actively loading snow. A couple of spots on the skin track were completely refilled between laps. The deepest spot was about 6" of snow loaded in about half an hour. It seemed like the wind was blowing at the right level to transport snow from one side of the ridge to the other, without blowing it away. Walking up the skin track in areas that were getting wind loaded I noticed small shooting cracks in a couple of spots, but only up to about 12" beyond my ski tips at most and that was isolated.