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Avalanche: Turnagain

Location: tincan common bowl

Date:
Observer:
Route & General Observations

-usual uptrack to the ridge above tincan common bowl
-light rain at parking lot, precipitation increased to intermittent-moderate above treeline and turned to coarse snow. skies were variable, mostly cloudy and flat lighting with patchy bursts of improved lighting.
-wind was fairly calm until treeline where winds picked up to approximately similar speed as sunburst weather station: active snow transport on ridgelines, cornices and slabs forming. Skintrack was mostly filled in, but still intermittently visible after less than 30 min above treeline.
-snow was mostly wet-moist until ~treeline.
-we skied the skintrack from bowl to trees, then trees out.

Avalanche Details
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Trigger SkierAvalanche Type Soft Slab
Aspect West SouthwestElevation 3100ft
Slope Angle 30degCrown Depth 24in
Width 100ftVertical Run 150ft
Avalanche Details

While ski-cutting small roll-overs, a medium-density slab ranging from 1-2' deep, was easily triggered at far skiers left of the lower tincan common bowl near ridge-line/skin track. Propagation was ~100ft of active debris, but cracks could be seen extending almost twice that distance to lower angle terrain. Avalanche was likely wind-transported new-ish snow, medium density slab, but chunks as large as 2'x4' and easily breakable under a skiers weight. Slab appeared to be very sensitive but low energy. We noticed slab settling/collapsing in close proximity which could also be felt on the descent adjacent to slide(slope angle ~20 degrees).

Below the bowl and through the trees, we could not trigger any other notable slabs or slides. Small loose snow sluff/slab would release (less than 6" deep and less than 30' across, barely releasing, running only a few feet. Once 2-300ft below treeline this effect was no longer appreciable.

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?No
Collapsing (Whumphing)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

obvious wind transport and previous days of high winds, some new snowfall. slab-failure/settling/collapsing POST-avalanche on adjacent slope just below skin track.

no instability seen/felt/heard on skinning up. pole probes made wind-transport slabs very high-suspicion.

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

from lot to ~300ft below treeline there was small moist rain layer on the surface with low-density wet snow beneath.