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Observation: Hatcher Pass

Location: Rae Wallace, Marmot Mountain

Date:
Observer:
Route & General Observations

IMB>Mid Rib SW Face Marmot>Marmot Weather Station, Clean off 2″ of rime on anemometer and solar panel>Descend Rae Wallace>IMB

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Observer Comments

Lack of any new, natural wind slab activity EXCEPT for:
Observed a few, not all, old glide avalanche paths showing ground. These areas are missing new snow since 11/16. They were covered earlier in the week. The question remains as to whether these areas are showing ground due to wind scouring or wind slab activity. Very difficult to judge. Old debris has brown coloring which appears to be glide avalanche debris. Very difficult in today's light to judge if there was new debris covering portions of the old debris. No new wind slab activity observed outside these specific areas.

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

Broken skies before 12:00, then a quick transition to overcast skies and flat light with a ceiling of approximately 8,000'.
Incoming storm with first snow flakes beginning to fall at 3000' @ 14:45
Calm to light winds all day, no snow transport 3000' - 4500'
30F @3000 @ 12:00
25F @ 4500' @14:00
Observed light rain along roadway near Turner Store @15:07

Snow surface

Rimed precipitation particles and DF.
5-20 cm/ 2-8" of F over 4F in wind protected areas
Exposed old rain and MF crusts in patchy distribution on SW face of Marmot and in windward locations throughout HP. It was easier to boot up instead of skinning. Crusts were textured, crunchy, a little forgiving, and allowed for compressing ski edges into the surface, boot toes could punch in nicely for booting.

Snowpack

At mid elevation on leeward aspects up to 12" of 4F to 1F- snow had been previously deposited in a patchy distribution, along cross loaded slopes. No Avalanches on these deposits, No Collapsing, No Cracking.
At upper elevation on leeward aspects, with top loading, old wind slabs were 12-18" deep, 4F to 1F sitting on a buried, thin rain crust, non reactive to ski cuts, hand test hard, on slopes 35-50 degrees in steepness. No avalanches, No Collapsing, No Cracking.
Marmot, West, 3700', 35 degrees steep. A pit was conducted with HS 1 meter/3.3 feet, lacked the thin crust in the mid pack, but did have a much thicker, more developed MF crust in the mid pack. Overall structure was good (with no noticeable problems layers, mostly right side up), high strength, low energy, lacking any propagation results, ECTX, CTN. Snowpack appears to consist of rounds and MF crusts with no faceting occuring around crust layers, and not facets or structural flaws at the snow/ground interface.
Impression was good to very good stability in the locations we traveled.

Photos & Video
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