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Avalanche: Turnagain

Location: Tincan Trees

Date:
Observer:
Route & General Observations

Tour up to treeline to assess the new snow character and how it is bonding with the old snow surface. Bonding was poor and several human triggered avalanches occurred on the small terrain features of the Tincan Trees.

Avalanche Details
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Trigger SkierAvalanche Type Soft Slab
Aspect UnknownElevation 2400ft
Slope AngleunknownCrown Depth 18in
WidthunknownVertical Rununknown
Avalanche Details

Several human triggered soft slab and wind slab avalanches on the Tincan rolls near and below treeline today. Appeared all avalanches were failing on buried surface hoar. Most were small due to the small terrain features. Most were around 12" thick, one wind slab was up to 3' thick at the crown. Also, one larger slab was noted under Jerome's Dome and was 1-2' thick, 150-200' wide and running 150-200 long. See photos.

There was NO visibility for any observations or travel above treeline.

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)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

All signs of instability present today - collapsing, cracking and recent avalanches.

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

Moderate snowfall (1/2 inch per hour) and gusty erratic winds (moderate to strong) at treeline. Very poor visibility. Storm day.

Snow surface

Low density powder, in the 5% range out of the wind. 10" at the parking lot and 12" at treeline ~2,400'.
Near treeline winds were forming soft wind slabs.

*Drove to Sunburst after tour, only 4" new snow and Johnson Pass, 3" new in parking lots. North end of Turnagain Pass clearly favored by this storm.

Snowpack

New snow was collapsing and sheering easily on the surface hoar it fell on in many locations. However, good bonding was also seen in some areas (likely due to skier traffic yesterday during the beginning of storm.

See pit photo for structure. Essentially, new snow fell over buried surface hoar which sits over 1-3" of near surface facets which sits on a harder layer of ice/wind packed snow/wind crust. The most reactive layer at this point looks to be the buried surface hoar. The culprit for the many human triggered avalanches today.

Photos & Video
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