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Observation: Turnagain

Location: Tincan to 3200'

Date:
Observer:
Route & General Observations

Standard uptrack to above Common Bowl, 3200′ on SW ridge. We could see evidence from Thursday’s storm of recent avalanches on North aspect of Tincan and Sunburst. There were a few groups out today that headed to the top of Common Bowl and none reported any whumpfs today.

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)?No
Cracking (Shooting cracks)?No
Observer Comments

Above freezing temps along the road, 36F at the vehicle at 3pm.
Recent avalanches from Thursday's storm including:
Tincan - Steep Northern terrain including Todd's bowl.
Sunburst - Steep Northern Terrain including Elevator Shaft and on a Northeast aspect.
Cornbiscuit - Steep Northern Chute, relatively small
Seattle Ridge - Below 2000' some wet loose activity, otherwise we have not seen any natural slabs release on the SE facing slopes like Repeat Offender.

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

Broken skies with patches of blue
Temps - above freezing at road (1000') SB Wx station- averaged 28F
Winds - Light from the East (5-10mph)
No precip

Snow surface

Superficial melt/freeze crust to 2500'. An inch of loose snow was found onto of this breakable surface crust above 2000'.
Above 2500' variable wind affected snow- supportable and unsupportable wind harden layers mixed with patches of softer snow.

Snowpack

Below 1500' layers of moist and wet snow were found below the superficial surface crust. Above 1500' dry snow was found under the superficial surface crust, and a 1" crust was found anywhere from 6-12" below the surface and disappears around 1900'.

Total height of snow in the alpine ranged from 30cm to 170cm. We probed a lot at this elevation band and could feel the crust near the ground almost everywhere we probed. We intentionally dug a pit in a thinner area, ~ 2 feet deep near the skin track just below the Ridge. Our pit was at 3100', SW aspect, 20 degree slope. Tests: CTC, CT11, ECTP18, ECTP13 failing 65cm below surface on loose large grain facets below Oct. melt/freeze crust. These facets were either sitting directly on the ground or on a thin deteriorating melt/freeze crust on the ground. We also had failure without propagation above the Oct. melt/freeze crust on a layer of 4F hard facets; ECTN14. Its important to note that we didn't completely isolate the melt/freeze crust in this test. See video and photo diagram for more details. The slab density was pencil hard gradually becoming 1Finger hard. Small 3mm buried surface hoar was also found 25 cm below the surface, but did not fail in any of our tests.

Photos & Video
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