Avalanche: Turnagain

Location: Lynx Creek drainage

Date:
Observer:
Route & General Observations

Rode into the Lynx Creek zone for a look at the avalanche activity from the past week as well as the snow structure. High point 3,500′.

Avalanche Details
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Trigger NaturalAvalanche Type Dry Loose Snow
Aspect SouthElevation 4000ft
Slope AngleunknownCrown Depthunknown
WidthunknownVertical Rununknown
Avalanche Details

Sun initiated loose sluffs on southerly aspects. We saw one in action, but most of them looked have occurred yesterday.

Also, noted several natural slab avalanches that were old from near the end of the large storm a week ago. See photos. All were in the D2 to D2.5 range. Captains Chair and other large paths only partially slid. We expected to see debris over the access trail, but did not. Large debris piles were seen under the steepest terrain, yet not as large as this area could produce.

In short, there is MUCH that has not slid in this drainage and most of those areas sit on the west side (east facing).

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

Sun effect was moistening the snow surface and causing shallow loose sluffs.

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

Sunny, valley fog along Turnagain Pass.
Temps in the 20'sF
Winds calm in drainage.

Snow surface

Roughly 5-6" of new snow from last Tuesday night.

Surface hoar seen from valley bottom to our high point at 3,500'. 5mm and sitting on very loose powder snow.

Snowpack

Poor structure. A 3 foot slab over facets at 2,100' and 5 foot slab at 3,000'. Slabs were generally on the soft side, fist hard to 1 finger and pencil just over the weak layer. Facets were around 4 finger to 1 finger hard. The NYE crust was found at 2,100' and was around 1cm thick and degrading.

No instability was seen within the slab itself.

We dug three pits but only tested in two of them with a PST.
3,000', W, 250cm snow depth (8 feet)
PST 120/130 Arrest

2,100', W, 190cm snow depth (6 feet)
PST 40/105 End

Photos & Video
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