Observation: Turnagain

Location: Girdwood valley

Date:
Observer:
Route & General Observations

Weather
Temps in the high 20’s/ low 30’s
Winds calm
no active precip.

Obvious Signs Of Instability
Recent Avalanches- Small surface sluffing (point release activity) in steep alpine terrain.
Shooting Cracks-NO
Collapsing – NO

Surface Obs:
1000′ – 1500’: 4 – 6” new snow on ground capped by very thin drizzle crust laid down this morning
(12/22).
1500 – 3200′: 6 – 10″ new snow on a moist melt/ freeze crust. HS ranged from 16” at the lower elevation
to 50” in a wind-loaded location at 3,100’.
Surface snow was low enough density that it really wasn’t forming a slab this early after the storm (wind-
loaded spots being the exception). Right side up snowpack.

Snow Below the Surface:
New snow appeared to be bonding quite well to the old melt freeze interface. I was specifically looking for
buried surface hoar today that has been ever present in both the Turnagain and Summit zones over the last
week. In my limited samples, I did not find this weak layer today and had no propagation in any of my
snowpits. This is good news but I won’t go so far as to say this buried surface hoar doesn’t exist in the
Girdwood valley…. Knowing how troublesome this layer can be, it’ll be worth taking the time to evaluate
individual slopes carefully before committing.

I did find small (2-3mm) facets below a crust in one snowpit though this layer was also unreactive in terms
of propagation.

Pit#1 (NE aspect, @2,500’) 30 deg slope
HS=28” (70cm)
ECTN23 @ new/ old snow interface (MF crust) 8”down.

Pit#2 (NE aspect, @ 3,000’) 29 deg slope
HS=20” (50cm) Purposely shallow area
ECTN15@ 2-3mm facets below a mid-pack melt freeze crust 8” down.

Pit#3 (N aspect, @3,100’) 34 deg slope
HS=50” (125cm) Wind loaded area below ridge
ECTN23 @ new/ old snow interface 20” down.

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