Observation: Turnagain

Location: Magnum - PMS Bowl

Date:

January 20, 2018 3:00pm

Observer:

Andy Moderow

Route & General Observations

Cornbiscuit lot up to Magnum – PMS Bowl.

Red Flags

Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.

Observer Comments

Minor sluffing on ~35 degree slopes in the bowl indicated larger sluff potential on steeper slopes!

Lots of mid storm slabs from last week, with debris under most of the north Cornbiscuit chutes, and an impressive view of the previously reported Sunburst slide! Partially filled in crowns were evident in the 2500-3500' elevation range, including across the valley on sunny side. Debris ran into PMS bowl as pictured below from a D2 slide on a SW aspect, with a crown extending ~400' just below the corniced ridge; in two places this slide appeared to have stepped down.

Weather & Snow Characteristics

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

Weather

Scattered clouds w valley fog most of the day between 1k-2k'
Temps in the teens, calm winds

Snow surface

No snow remains in the trees below the cornbiscuit alders, but clearings in the alders and above alder line featured a stout supportable crust to 2500', and a thin crust up to 3000'. A trace of near surface facets were over the crust at 1500', increasing steadily to 6" @ 2500'. Above 3000', ski penetration ranged from 4-8" in near surface facets

5-20mm surface hoar observed on all snow covered surfaces, with the largest surface hoar observed at highest elevations.

Snowpack

Quick pit at 3300', SW aspect, 20 degree slope, HS=195cm. HS ranged from 150cm to 240cm in the 200 yards leading up to the pit. The New Years Buried Surface Hoar was visible 95cm down.

CT 22,25 PC and ECTN 20 down 40cm in a midstorm density change. The Buried Surface Hoar didn't fail in compression tests, but it popped with energy with easy force in a shovel shear test. The slab above and the bed surface below the BSH was one finger hard - see photo below!

Photos & Video

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Debris from midstorm slide into PMS bowl

Closeup of crown just below the Magnum ridgeline, with two smaller crowns underneath it

Pit structure as referenced above

20mm surface hoar at 3300'

20mm moss at 1000'

Location

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