Avalanche: Hatcher Pass

Location: Marmot S ridge/Death Gully remotely triggered avalanche

Date:

November 18, 2023 8:34pm

Observer:

Barker/ Workman/Paul Forecaster

Route & General Observations

It was a touchy and spicy day in the backcountry!! Toured up Marmot south ridge to do post storm observations and investigate instability in the snowpack. No cracking or collapsing were observed on our route up the south ridge however, we saw two new large remotely triggered avalanches on the NW aspect in the Death Gully and adjacent slope on the SE aspect of Marmot 2. Lots of recent cracks were observed on both sides of the ridge from fish point to the mid-rib. We also observed numerous small to large naturals from the 11/15-11/17 storm. READ FORECASTER COMMENTS!

Contact, Location & General Observations

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Forecaster Comments

Timeline of events: Around noon on 11/18 Skier A descended the southwest face on Marmot and the entire face cracked at once without sliding. See photo. At the same time Skier B was standing on the ridge and observed Skier A remotely trigger the large avalanche in the Death gully AND the SE face of Marmot (part of Marmot 2) on opposite sides of the ridge AT THE SAME TIME. This should make anyones hackles stand up.

Avalanche Details

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Trigger	Skier	Remote Trigger	Yes
Avalanche Type	Soft Slab	Aspect	Northwest
Elevation	3900ft	Slope Angle	unknown
Crown Depth	3ft	Width	200ft
Vertical Run	1000ft

Avalanche Details

We observed a new avalanche today that didn't exist the day prior. When skinning uphill we asked another party about the avalanche and they said it was remotely triggered while skiing another run approximately 300-400 yards away . At approx 12pm a skier descended the SW face which cracked in numerous locations at the same time AND remotely triggered both avalanches, on opposite sides of the ridge, at the same time. The death gully avalanche was huge D2.5, approximately 1 meter/3ft deep crown and ran 1000+ ft. It failed on the crust/basal facet layer near the ground and stepped down to the ground in some locations. SE face/Marmot2 avalanche was also approximatly 2-3' deep and D1.5 in size.

Red Flags

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Obvious signs of instability

Recent Avalanches?	Yes
Collapsing (Whumphing)?	No
Cracking (Shooting cracks)?	Yes

Observer Comments

Numerous recent avalanches from 11/16-17 on all aspects, mostly above 3500'. More info in todays forecast.
Observed two remotely triggered avalanches today, Marmot NW aspect Death gully @3900' SS-ASr-D2.5-0 and Marmot SE aspect @ 3800' SS-ASr-D1.5-O.
We observed numerous recent cracks likely from today on both sides of the ridge. See photos. We did not experience any whumping.

Weather & Snow Characteristics

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Weather

Chilly, calm, clear beautiful bluebird day
-5 deg F at 10am at 4500'
2 deg F at 10am at 3550'

22" new snow and 3" SWE 11/15-11/17

Snow surface

Surface snow- stellars and rimed stellars
Mostly fist hard snow with visible wind affected surfaces from beginning of storm 11/15

Snowpack

Lower Marmot S ridge SSW
3500'
HS 75cm 24> slope
ECTN9 down 15cm
ECTN16 down 30 cm
ECTN19 down 45cm
ECTN 20 down 65cm on facets
CT15 PC - failed at the ground on facets .5-1mm

Photos & Video

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