Avalanche: Hatcher Pass

Location: Marmot SW ridge to mid rib decent

Route & General Observations

Skinned up Marmot South ridge and traveled along the Marmot ridgeline to about 4,000 ft then descended the “mid-rib”. Observed widespread cracking and whumping in previously wind loaded pockets.  Slabs that exist are soft and discontinuous, but just cohesive enough to act as a slab over the weak, ugly, depth hoar/melt freeze crust sandwich. Some upper elevation areas near ridgelines previously received stronger winds and have stiffer, thicker (up to 20 inch) slabs that are more consequential. No new naturals observed. Most avys from last week are dusted over and not visible anymore.





Avalanche Details
If this is an avalanche observation, click yes below and fill in the form as best as you can. If people were involved, please provide details.
Trigger SnowboarderAvalanche Type Hard Slab
Aspect West SouthwestElevation 3800ft
Slope Angle 38degCrown Depth 10in
Width 25ftVertical Run 60ft
Avalanche Details

Marmot SW face HS-AR-R2-D1.5-O, 5-20 inches deep x 60ft wide x 400 feet long
Marmot SW face HS-ARy/r-R2-D1-O, 10 inches deep x 20 feet wide x 60 feet long
Marmot SW face HS-ARy-R2-D1-O, 10 inches deep x 20 feet wide x 60 feet long

Mostly smaller human triggered avalanches, some of which appear to have been triggered from a distance (remotely) and sympathetically from other avalanches. These avalanches likely occurred on Dec 21. Their sensitivity appears to have changed, becoming more stubborn to trigger 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)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

Recent (12/21) human triggered and remotely triggered avys on SW/W faces on Marmot 4000 feet. Significant cracking/whumping (10-30 feet wide) on route up.

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

Clear, cold 2 deg. F.

Snow surface

Surface hoar (1mm), near surface facets, and decomposing grains.


See pit attachment.

Photos & Video
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