Observation: Turnagain

Field Observations
December 30, 2014

Route
Tincan to 2800′

Weather
Temps: high 20- low 30’s
Rain line: 1100ft
Winds: 20’s w/ Gusts in 40’s mph
Skis: obscurred
Precip: light to moderate w/ blowing snow

Obvious Signs Of Instability
Recent Avalanches-NO
Shooting Cracks-NO – small isolated cracks under skis, no shooting cracks
Collapsing – NO

Surface Obs
1000′ – 5” new heavy wet snow
1500 – 2000′ – 8-10″ new pasty snow with areas of wind scoured snow
2000 – 3000′ – large areas of wind scoured snow with isolated pockets of wind deposited snow (1-2′)

Snow Below the Surface:
Pit @ 2100′ – Aspect: W, slope 10*, HS: 158cm, 32cm of wind deposited snow from Xmas and Dec.29-30
sitting on 2mm buried surface hoar. Below this layer is a 32cm(12″) slab from Dec.14-17. This slab is
mostly rounds with a mid pack melt/freeze layer about 8cm thick. We also noticed vertical peculation
melt/freeze throughout the slab. Below this slab sits the larger surface hoar (5-8mm) sitting on a raincrust.
Results: ECTP27 failed at 56cm (22″) from the surface on 2mm surface hoar/old snow interface. (See
picture of pit.)

The sustained high winds appear to be scouring lots of terrain features like nobs, ridges, small slopes. We
noticed some isolated pockets of wind loading low on features of the Tincan trees. These pockets were
loaded low on features and averaged 1-2′ deep. Due to the gentle terrain features of Tincan Trees and the
variable wind direction most aspects had signs of scouring and wind loading. Many terrain features were
completely blown clean to denser old snow layers where you can see erosion around old ski tracks and old
skin tracks. See picture below. Visibility was limited and we couldn’t see much into the Alpine. It is
unknown how much top loading has occurred on larger, steeper slopes in the Alpline.