Avalanche: Hatcher Pass

Location: Lower Marmot

Date:
Observer:
Route & General Observations

Post storm tour (after the road re-opened Wednesday at noon) to observe recent avalanches and instabilities in the snowpack. Observed 5 to 6 significant COLLAPSES up to 2 feet deep and CRACKING up to 50′ wide during our tour on a SW aspect. We turned around half way up Marmot due to red flags and low visibility.

Recent storm slab, wind slab, persistent slab and dry loose avalanches from 3/30 on SE Marmot gully 2, NE Face of Government, and South Idaho Peak in addition to other small avalanches observed today.

Avalanche Details
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Trigger SkierAvalanche Type Soft Slab
Aspect East SoutheastElevation 3600ft
Slope AngleunknownCrown Depth 18in
Width 50ftVertical Run 300ft
Avalanche Details

Remotely triggered persistent slab on a ESE aspect from 150 feet away. The slab failed on buried facets on top of the sun crust. This party also reported a large collapse today on their tour.

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

Significant CRACKING up to 50' wide and COLLAPSING 2 feet deep on the buried facets sitting on the crust layer on our tour today between 3000-3600' on a SW aspect.
We observed 5 to 6 large collapses today.
Recent wind slab, storm slab, persistent slab, and dry loose avalanches that happened mid to end of storm 3/29. Another party reported remotely triggering a persistent slab on a ESE aspect at approx 3600' from 150 feet away. More details in "Avalanche Details"

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

6-10" of new snow on 3/29 with moderate to strong gusts SSW for 12 hours.
Temps:
12 deg. F at 1200 @ 4500'
22 deg. F at 1200 @ 3550'

Snow surface

New snow and PP including stellars, graupel, and ice pellets. 6-10" of new snow is cohesive and acts like a slab in specific locations. We observed 1 to 2 new thin breakable crusts within the new storm snow today with up to 10 cm of graupel on either side of the crust. This brings the crust count up to 7 in the current snowpack in specific locations.

Snowpack

see pit

Photos & Video
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