Avalanche Activity

Cooke City
Scotch Bonnet
Small (very small) natural wind slab near Lulu Pass
Incident details include images
Scotch Bonnet
SS-N-R1-D1-S
Elevation: 10,100
Aspect: S
Coordinates: 45.0566, -109.9510
Caught: 0 ; Buried: 0

GNFAC forecasters witnessed this very small wind slab on 12/7/21 near Lulu Pass outside Cooke City.


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Northern Gallatin
Hyalite - East Fork
Ice climbers triggered small avalanches in E. Fork Hyalite
Incident details include images
Hyalite - East Fork
SS-AFu-R1-D1-S
Elevation: 7,600
Aspect: NE
Coordinates: 45.4539, -110.9210
Caught: 0 ; Buried: 0

The slide was on the ice climb in Comet Alley.

From email (12/5/21) : "Small avalanche triggered while approaching ice climb in East fork of Hyalite basin. 

Another D1 natural avalanche was observed later in the day similar aspect/elevation

NE @7600’
SS-AFu-D0.5-I"


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Northern Madison
Big Sky Resort
Explosive Triggered Wind Slabs at Big Sky Resort
Big Sky Resort
SS-AE-D2
Coordinates: 45.2760, -111.4360
Caught: 0 ; Buried: 0

Big Sky Resort Ski Patrol reported triggering wind slab avalanches up to 1 ft deep below alpine ridgelines using explosives during avalanche mitigation work on 11/25/2021. Some of the slides broke down into older snow.


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Northern Gallatin
Mt Blackmore
Shooting Cracks Mt Blackmore
Incident details include images
Mt Blackmore
Elevation: 9,700
Aspect: SE
Coordinates: 45.2648, -111.0000
Caught: 0 ; Buried: 0

Skiers on Mount Blackmore observed cracking within the freshly wind-loaded snow on a southeast-facing slope just below the ridge


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Out of Advisory Area
Livingston
Natural avalanche and powder cloud on Black Mtn
Incident details include images
Livingston
U-N
Elevation: 10,000
Aspect: N
Coordinates: 45.4712, -110.4670
Caught: 0 ; Buried: 0

This powder cloud from a large avalanche was seen on Black Mountain, up Pine Creek outside Livingston. Located outside our advisory area it is a sign of unstable snow, likely from wind-loading, that can be found throughout southwest Montana.


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Cooke City
Henderson Mountain
Natural avalanches (on persistent weak layer) near Cooke
Incident details include images
Henderson Mountain
SS-N-R2-D2-O
Elevation: 10,000
Coordinates: 45.0524, -109.9450
Caught: 0 ; Buried: 0

From email 11/15/21: "east Henderson had a fresh slab avalanche- on a NE aspect around 10,000'.  It appeared to have failed on a weak layer near the ground, and I'd guess it was about 2-3' deep and 300'+ wide.  (photo attached)

Also noted some other natural slab avalanches on some northerly aspects of Miller Ridge.  (steep rocky starting zones).  And noted a couple big slab avalanches on NE erly aspects up Republic Creek too. Similar thing there:  steep, rocky, wind loaded starting zones."


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Cooke City
Scotch Bonnet
Natural wind slabs on Scotch Bonnet
Scotch Bonnet
SS-N-R0-D1.5-I
Elevation: 9,900
Aspect: SE
Coordinates: 45.0566, -109.9510
Caught: 0 ; Buried: 0

From email 11/10: "noted two small cornice triggered slab avalanches on a SEerly aspect of Scotch Bonnet Mountain. They looked to be fresh this morning, involve just new snow, and were about 25' wide each."


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Bridger Range
Saddle Peak
Natural on Saddle Peak
Incident details include images
Saddle Peak
SS-N-R1-D2
Elevation: 9,000
Aspect: NE
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0

From obs. 11/10:  "Fitness skinning around Bridger Bowl yesterday and noticed a fairly large, new avalanche on the east face of the North peak of Saddle. Maybe 100 feet below the ridge, about 100 wide at the crown, ran thru the rock bands but not over the cliff. Was taken back by the clean propagation." -Albert


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Bridger Range
Naya Nuki Bowl
Skier caught in slough in the The Great One
Incident details include images
Naya Nuki Bowl
L-ASu-R1-D1.5-S
Elevation: 9,000
Aspect: N
Coordinates: 45.8883, -110.9590
Caught: 1 ; Buried: 0

From e-mail 11/7/21: "Today, my partner and I set out to ski The Great One, with a plan to come up and over Sac Peak and then walk the ridge to Naya Nikki before skiing the Great One into Airplane Bowl. We found more snow than expected at the TH, about 6inches. On our way up to the pass just north of Sac we noticed the characteristic wind stripping down to scree on the trail to the pass. On one of the switch backs we were able to get about an 1-2” deep wind slab to propagate but not move down slope. Given the depth, we didn’t put too much stock into this. We proceeded to walk the almost snow free trail over to Naya Nuki before booting down to the top of the Great One. The skiers left side of the Couloir had some obvious wind load and after a few ski cuts felt comfortable continuing to ski. After my partner skied the majority of the top section, I followed and was entrained and taken for a slide in my own ‘slough’. I was carried about 40’ before I stopped, while the slough kept running for another 100-150’ arresting on the shallower angled slope before the break in the Couloir wall that feeds into Airplane Bowl. The entrained width of moving snow was about 3-5’ wide. There were no injuries, and we continued down to the base of the Couloir, deciding it would be more dangerous to try and go back up to get out. Once in airplane bowl we saw multiple large slides that ran last night, syn-storm. Most of which came down from the East face of Sac. A few 200-300’ wide and running the length of the bowl. Early season hubris, and is not even thinking about overnight wind totals has us more or less absent minded when we set out this morning. A mistake that could’ve been a lot worse if the slough had taken a larger wind pocket with it, and carried me over the same aspect that led to the fatality in the Great One last fall. No pictures of the slough, attached is a grainy cell phone pic of the slides in Airplane Bowl."


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