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Avalanche: Hatcher Pass

Location: Marmot SW face

Date:
Observer:
Route & General Observations

Mid-elevations, all aspects, highly discontinuous and shallow snowpack (HS 25cm-40cm), heavily scoured and loaded in isolated to specific areas, localized whumphing and shooting cracks. Persistent slab sensitivity stubborn to touchy.

Upper elevations, all aspects, in specific locations where winds deposited more continuous, thicker and cohesive hard slabs the persistent slab avalanche problem was more significant, up to 85cm (3 feet deep), averaging 45cm (1.5 feet deep). Persistent slab sensitivity touchy. Human triggered avalanches likely, remotely triggered avalanches possible.

Old raised tracks on some steep upper elevation slopes, sastrugi, supportable and breakable crusts and old wind slabs. Slabs begining to facet out, areas without cohesive slab are pure facets.

The gem for skiers or boarders would be finding a zone that lacks the slab and skiing pure square powder. We did not find it.

 

 

Avalanche Details
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Trigger SkierAvalanche Type Hard Slab
Aspect South SouthwestElevation 3900ft
Slope Angle 40degCrown Depth3ft
Width 60ftVertical Run 900ft
Avalanche Details

avg crown height 1.5 feet;
touchy trigger from low angle (30 deg) ridgeline

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

Cracking an whumphing abundant. Localized up to 15 meters, depth 25 to 40 cm. Mod strength, Poor structure, high energy.
Recent avalanche same aspect and elevation, winds Jan 5?

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

Ta= -9.2C, Ts= -7C @ 3400', Calm, surface snow NSF 0.5

Snow surface

NSF, wind board 2-6" thick, wind exposed xtra fragile faceted crust

Snowpack

Old wind slab over weak mid-pack over extra weak depth hoar

Photos & Video
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