Avalanche: Hatcher Pass

Location: Marmot

Route & General Observations

IMB>Rae Wallace

25F, calm, overcast skies @ 13:00 @ 3500′
22F light east winds, overcast > broken skies @ 14:30 @ 4500′

Avalanche Details
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Trigger SkierRemote Trigger Unknown
Avalanche Type Dry Loose SnowAspect South
Elevation 4400ftSlope Angle 37deg
Crown DepthunknownWidthunknown
Vertical Run 600ft  
Avalanche Details

Dry loose avalanches 12/1/2019, after 6" of new snow overnight (3000-4500'):
Some natural, small (D1), dry loose avalanches on steep slopes (35deg +), Rae Wallace, South face Skyscraper, likely in many other areas but visibility limited our observations.
Human triggered, small (up to D1.5), dry loose avalanches on steep slopes (35 deg +). Numerous on Microdots south face and Microdot's Swimming Tim's.

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

No avalanches other than small up to D1.5 dry loose.
Some new glide cracks forming and expanding. See picture of Marmot.
No cracking, No collapsing, No slab avalanches observed today.
Old Thanksgiving wind slab has bonded well and is now buried 6" deep @ 3-4.5k'.

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

6" new 3-4.5k'
25F, calm, overcast skies @ 13:00 @ 3500'
22F light east winds, overcast > broken skies @ 14:30 @ 4500'

Snow surface

6" new snow overnight, low density, not a significant load
Light winds were not moving snow at ridgeline at 14:30 @ 4500'
Mid elevation has some previously wind protected zones where ski penetration is up to 2 feet deep.
Above 4000', the old Thanksgiving wind slab appears to be widespread, supportable, and limits ski penetration to 6" in many locations.
Steep slopes with previous dry loose debris are begining to firm up.


No snowpits today.
Hasty tests confirmed Thanksgiving wind slab well bonded to older snow, good stability.

***Glide cracks continue to form and expand. Marmot mountain has new glide cracks we observed 2 days ago, these have expanded as of today. The Mid Rib on Marmot is not a good up-track right now as the glide hazard is high consequence and we would not be surprised if this glide released very soon.

Cornices have grown significantly in size, due to the Thanksgiving new snow and strong winds.

Photos & Video
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