Observation: Hatcher Pass

Location: Marmot Mid Rib

Route & General Observations

Another flat light tour up Marmot Mid Rib to assess stability and structure within old/new storm snow and wind slabs over the last 7 days. We did not experience any whumping and had limited shallow cracking within the new surface storm slabs building throughout the day. Windward aspects are shallow from recent wind scouring while leeward aspects are harnessing a deeper snowpack with good snow quality.

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?No
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

We observed shallow cracks up to 3 inches deep that didn't propagate further than 5 feet on isolated features near ridges at 4000'.

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

2" new snow with 0.1" SWE accumulated today at 3550'

New snow from 12/17-18
IM/3550': 12 inches HN 1.8" SWE
Frostbite/2700': 10" HN 1.3" SWE

Wind slabs from 12/16-17 are more cohesive and acting like slabs at upper elevation and near ridgeline .
Light winds in the teens today with SE gusts 17-20mph at 4500'

Temps@ 12pm
Marmot /4500':16degF
IM/3550': 21deg F

Snow surface

Snow surfaces are variable depending on the aspect. Windward aspects, mostly SE to SW are shallower and scoured down to the crow berries and blueberries in some locations with 4-10 inches of snow. Leeward aspects, mostly W to NE are harnessing a significantly deeper snowpack with up to 4-5 ft of snow. Snow surfaces are cohesive and barely acting like a slab in isolated locations at upper elevation near ridgeline while below 3500' and wind protected locations are soft and creamy. 1-2" thick shallow stubborn soft slabs were forming at upper elevation ridgelines between 12-3 today.


Two pits were dug today.

#1 3550' HS 65cm SW aspect
ECTN35cm down on rounding facets

4100ft 34 degrees
HS 130 cm
130-105 F
105-85 4F
85-83 4F+
83-55 1F-
55-45 4F
45-35 F moist rounding faucets
35-33 1F wind slab deteriorating
33-25 4F
25-23 1F old wind slab deteriorating
23-10 1F
10-8 old melt freeze crust
8-2 moist depth hoar facets
Ground crust (2-0)
ECTN27 @75
CT13RP @75
35 cm down old near surface facets 0.2-0.5 mm
Rounding depth hoar at base!

Photos & Video
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