Observation: Turnagain

Location:
At the bench along Taylor Creek between Sunburst and Magnum. Rolling terrain in
valley just at treeline.

Weather:
Thin mid-elevation fog band which reduced visibility above treeline. Visibility
was good from highway to top of treeline. Temperature was ~20 F. A light
northerly breeze blowing down valley, otherwise mostly calm winds below treeline.

Signs of Instability:
Recent avalanches – No
Cracking – No

Collapsing – Yes! Had large snowpack collapse while 1 skier was standing and 1
additional skier took skis off and put boot through snowpack on a small 21
degree, W-facing knoll at ~1900′. (There was a pit dug on this same slope in the
past couple of days)
Felt like a 20 x 20 m slab that collapsed as 1 piece (entire area of the knoll
slope) and dropped ~10cm on the basal facets. The 2 skiers on the slab felt the
large jolt. The 3 other skiers nearby also heard it.

Snow Surface Observations:
1000-1200′ – Crusty surface that was supportable to skis but not boot penetration
1200-1700′ – Very thin (2mm) crust with 2″ of low density snow on top
1700-2000′ – 3-4″ of low density snow over denser, supportable snow

Dug pit at ~1800′, NW facing knoll, (~150m from where we got collapsed snow).
ECTP-18; Sudden Planar on ~10cm of basal facets. Slab collapsed as one large
block of snow that did not break apart even when it hit the ground..