Avalanche Activity

Northern Gallatin
Mt Blackmore
Kicking wind slabs on Blackmore Trail
Incident details include images
Incident details contain video
Mt Blackmore
SS-ASc-R1-D1-O
Elevation: 8,700
Aspect: E
Coordinates: 45.4444, -111.0040
Caught: 0 ; Buried: 0

Toured up to the NE shoulder on Mt. Blackmore yesterday. Winds were strong and variable, but mostly gusting from the S-SW. A lot of snow was moving around, skin tracks were filled in very quickly, and you could actively see small cornices starting to build on the lee side of the ridge. 

On the descent, I intentionally triggered a small wind pocket in one of the chutes in the cliffs near the trail at 8700 ft. I included a video. It was D1 and about 5 inches deep at the crown. I think just a good reminder that even in the trees, the tops of those chutes get wind loaded and can definitely slide


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Northern Madison
Big Sky Resort
BSSP Trigger Avalanche - Cold Springs
Incident details include images
Big Sky Resort
AE-O
Aspect: N
Coordinates: 45.2760, -111.4360
Caught: 0 ; Buried: 0

From BSSP Observations: "A wind slab triggered near the top of Cold Springs ran down and triggered a persistent slab around constriction level (see pics). This deeper failure occurred about 20cm off the ground at the Oct/Nov interface in a snowpack that was only about 1m deep." 


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Bridger Range
Bridger Bowl
Skier triggered hard wind slab at Bridger
Bridger Bowl
HS-ASc-R2-D1.5-I
Elevation: 7,800
Aspect: NE
Coordinates: 45.8170, -110.9250
Caught: 0 ; Buried: 0

Skier triggered wind slab avalanche around 2pm, along the edge of north Bowl and Bronco near "The John". Crown 6-10" deep and 30 feet wide, hard slab of recent drifted snow. HS-ASc-D1.5. Strong wind blowing steady from the south-southwest and transporting snow, filling in tracks rapidly.

Immediately after this slide, I saw what I assume was skier triggered, slide of similar size a little further down the bowl with crown drifting in. Beacon check of debris produced no signal, barely deep enough to bury someone.


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Bridger Range
Bridger Bowl
Skier triggered avalanche NE aspect Bridger.
Incident details include images
Bridger Bowl
HS-ASu-R2-D1.5-I
Elevation: 7,800
Aspect: NE
Coordinates: 45.8264, -110.9290
Caught: 1 ; Buried: 0

From obs: "Triggered a small(d1r1?) wind slab off the bridger chair in bounds at bridger. Little skiers right of bumble chute on the roll over skiers left of bronco. NE face. Rollover around 35 degrees mellowing throughout the run. The face had tracks from earlier today before i triggered the slide. I was able to self arrest and stop myself before being carried. The crown was around 20-25 ft wide and the slide ran roughly 100ft downhill before stopping. Both myself and my partner skied away unharmed."


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Northern Gallatin
Hyalite - main fork
Skier triggered wind slab east aspect Hyalite
Incident details include images
Hyalite - main fork
SS-AS-R1-D1-O
Elevation: 8,300
Aspect: E
Coordinates: 45.4472, -110.9620
Caught: 0 ; Buried: 0

Saw a group of skiers trigger a small wind slab avalanche on an eastern aspect at around 8,300' in the main fork of Hyalite in "Candy Land" just south of the climb Big League Chew at 2:00pm on Saturday (11/26). Crown looked to be around 2" to 1' and 90' wide. The slide ran maybe 100'. No skiers were caught. It was triggered as the first skier traversed out onto the intended ski line from the trees which they skinned up. The fracture extended from the tips of the first skiers skis and ran across the slope and underneath a small cliff band. The group skied out on a slightly lower angle slope adjacent to the slide. My group watched from below an adjacent ski run approximately 300 yards away as the slide happened. We had dug a pit on a similar aspect in the area approximately 30 minutes before the slide and found 85cm of snow with a weak layer at 42-45cm which failed CTs but we couldn't get propagation. (CT22, ECTN21). It looked like this was probably the layer that failed in this slide.


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Northern Madison
Beehive Basin
Natural loose snow and rollerballs, Beehive and Bridger
Incident details include images
Beehive Basin
L-N-R1-D1
Elevation: 9,700
Aspect: S
Coordinates: 45.3508, -111.4000
Caught: 0 ; Buried: 0

Obs from Beehive 11/25: "Lots of moving snow on south facing aspects. most of the chutes to the [lookers] right of the (4th of July couloir) had slid, it looked like it was mostly limited releases from sun warmed rocks."

GNFAC Forecaster at Bridger on 11/25 saw natural rollerballs and pinwheels on steep, rocky south facing terrain. (photo).


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Northern Madison
Big Sky Resort
Large natural avalanche on deeper weak layer at Big Sky
Big Sky Resort
HS-N-D3-O
Elevation: 10,000
Aspect: N
Coordinates: 45.2760, -111.4360
Caught: 0 ; Buried: 0

From BSSP (11/24): The Whale on the NSS slid naturally at some point in the past 24 hours,
likely broke into deeper layers, and ran well past the Meeting Trees- estimated D3 slide. There is
weakness in the alpine snowpack on some northerly aspects in the alpine...


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Bridger Range
Bridger Bowl
Human-Triggered Avalanche In Bridger Gully
Incident details include images
Bridger Bowl
SS-ASu-R2-D1.5-I
Elevation: 7,650
Aspect: E
Coordinates: 45.8156, -110.9230
Caught: 1 ; Buried: 0; Killed: 0

From IG Message: "I read the avalanche report this morning and felt comfortable skiing. we made a plan to ski Bradley’s Meadows but ended up skiing Bridger Gully to the 3 Bears after discussion and feeling comfortable and confident in the snowpack. we did not experience any whoompfing or have any other concerns on the approach. 

The bottom of Bridger Gully to 3 Bears is where I triggered the avalanche. My partner dropped in first and skied safely out of the potential slide area. I followed up and on my first turn, triggered the slide. To me it looked like it was around 8” deep and was around 15’ wide at the crown.

My partner had eyes on me the entire time as the slide carried me about 40-45 yards. I was on top the entire time and was able to ski out at the end. I suffered no injuries. 

We skied out and talked to other skiers about our experience."


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Northern Madison
Beehive Peak
Skier triggered avalanche in Beehive
Incident details include images
Beehive Peak
WL-ASc-R2-D2-I
Elevation: 10,300
Aspect: S
Coordinates: 45.3539, -111.4050
Caught: 0 ; Buried: 0

From Obs: "I wanted to share about a small avalanche I set off today. Snow was getting warm on my way up 4th of July couloir (pinwheels coming off lookers right wall started around 11:30) top half took a long time due to deep snow so I was suspicious of the pinch. Ski cut it during the descent (12:30p) and set off a wet slide (point release) that picked up quite a bit of steam as it came out the bottom. Big enough to injure/bury a skier."


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Bridger Range
Bridger Bowl
Small avalanche Lower Nose
Incident details include images
Bridger Bowl
SS-R1-D1-I
Elevation: 7,500
Aspect: E
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0

Skiers at Bridger Bowl observed a small avalanche that was likely human-triggered on the Lower Nose. New snow and wind combined to created instabilities on slopes. The ski area is closed and represents a backcountry snowpack until the ski patrol begins avalanche mitigation in preparation for the opening. 


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Bridger Range
Bridger Bowl
Skier triggered wind slab at Bridger
Incident details include images
Bridger Bowl
SS-ASc-R2-D1.5-I
Elevation: 7,600
Aspect: NE
Coordinates: 45.8168, -110.9240
Caught: 0 ; Buried: 0

At 1:30pm on 11/23 I intentionally triggered a fresh drift of snow in a narrow avalanche path along the edge of the north bowl at Bridger. Northeast aspect at 7,600’ elevation. The crown was 6-8” deep consisting of snow that fell today, 20’ wide and ran 250’ vertical. SS-ASc-R2-D1.5-I. 

Wind was moderate, gusting strong out of the north and west and transporting snow. There were 3-4” on lower mountain and 7-8” new up high. Snowpack is 1-2’ deep. Prior to this storm, snow close to the surface had turned to small (1-1.5mm) facets during previous cold weather, capped by a thin crust (wind or sun) on many slopes. 


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Northern Madison
Beehive Basin
Loose snow slides in Beehive
Incident details include images
Beehive Basin
L-N-R1-D1
Elevation: 9,500
Aspect: SW
Coordinates: 45.3407, -111.3910
Caught: 0 ; Buried: 0

From IG message: "We saw a few decent sized point releases in the same zone on Sunday, 11/20, the day after the wind slab. All occurred on SW aspect within approx 15 min at 2:30. The air temp rose noteably shortly before and the sun was baking the SW aspect."


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Northern Madison
Big Sky Resort
Explosive triggered hard slabs at Big Sky
Incident details include images
Big Sky Resort
HS-AEc-R2-D2-O
Elevation: 9,000
Aspect: E
Coordinates: 45.2862, -111.4300
Caught: 0 ; Buried: 0

Triggered with 4lbs, after they were not affected by 2lbs shots yesterday. The crowns were in the 12” range and hard slabs. The weak layer is subtle-trapped lower density (but still 4F) above the crust, with tiny facets mixed with rounds. The slides were not running directly on the crust, but just above, leaving 2-3 cm’s behind on top of the crust.


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Northern Madison
Beehive Basin
Natural Avalanche in Beehive Basin
Incident details include images
Incident details contain video
Beehive Basin
SS-ASu-R1-D1.5-G
Elevation: 9,000
Coordinates: 45.3407, -111.3910
Caught: 0 ; Buried: 0

My partner and I were skinning up a west-facing slope in Beehive Basin when we stopped out of the wind at a large rock outcrop.

Shortly after stopping to re-assess, a small, wind-deposited, pocket of snow popped off the rock face above us triggering a soft-slab slide which gained momentum and stepped down through a rocky choke, fanning out in the open face below the rocks, before coming to a stop directly at our skis. 

We witnessed no additional natural avalanches that day or found any significant instabilities in the snowpack on adjacent slopes. We can only attribute our near-miss to luck, if the avalanche had occured five minutes before we stopped (while skinning across the slope), or five minutes after (while continuing upslope to our desired objective), our day might have ended quite differently. 


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Northern Gallatin
Hyalite Peak
Large Natural Avalanche on Hyalite Peak
Incident details include images
Hyalite Peak
HS-N-R2-D2-G
Elevation: 10,298
Aspect: N
Coordinates: 45.3810, -110.9610
Caught: 0 ; Buried: 0

Toured into divide basin on Friday. Looking at the north face of hyalite peak we saw a slide that went to the ground, and was about 150 feet wide. It possible this slide propagated further, but severe wind loading was actively occurring and it was hard to tell if the crown had been filled back in. We dug a pit at 9300 feet on a SÉ aspect and found a 80-100 cm HS and right side up snow pack with minor faceting below a crust 30 cm from the bottom. 


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Bridger Range
Bridger Bowl
Wind slabs mid-slope at Bridger Bowl
Incident details include images
Bridger Bowl
AS-R1-D1
Coordinates: 45.8150, -110.9230
Caught: 0 ; Buried: 0

From obs: "triggered a small wind slab in sluice box today. this was not a surprise as all of the wind loaded areas had shown cracking and instability on the way up. though these other areas exhibited the same instability, this little pocket in sluice was the only spot steep enough to run."

submitted to us via IG: "triggered this large wind slab below Bridger Lift this morning [11/18]. It propagated quite a ways."


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Bridger Range
Beehive Basin
Small wind slabs at Bridger and Beehive
Beehive Basin
AS-R1-D1
Coordinates: 45.3407, -111.3910
Caught: 0 ; Buried: 0

Small wind slab avalanches (both natural and skier triggered) along the Bridger ridge and in Beehive Basin.

See obs:

Bridger Obs

Beehive Obs


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Cooke City
Henderson Mountain
Natural Avalanche Henderson Mountain
Incident details include images
Henderson Mountain
SS-N-R2-D2-U
Elevation: 10,000
Aspect: NE
Coordinates: 45.0524, -109.9450
Caught: 0 ; Buried: 0

From email: "We noted one recent slab avalanche today on a NE aspect of Mt. Henderson, around 10,000.  We were skiing nearby on Nov. 11-12 and did not notice this slide, but that may have simply missed it (that slope becomes shaded by about noon this time of year and there was lots of wind affected snow in that area.)"


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Southern Madison
Tepee Basin
Avalanche Crowns in Tepee Basin
Incident details include images
Tepee Basin
N-R2-D2
Elevation: 9,500
Aspect: E
Coordinates: 44.9041, -111.1850
Caught: 0 ; Buried: 0

A number of Avalanche Crowns on an east aspect at 9500 ft.


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Cooke City
Henderson Mountain
Large collapses near Cooke City
Incident details include images
Henderson Mountain
AS
Elevation: 9,800
Coordinates: 45.0524, -109.9450
Caught: 0 ; Buried: 0

From email: "Skied around Mt. Henderson the last 2 days-... we experienced at least 6 large collapses while touring the last 2 days, often after 10+ people up the same skin track."


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Northern Gallatin
Hyalite Peak
Wind slabs on Hyalite Peak
Incident details include images
Hyalite Peak
SS-ASc-R1-D1-I
Elevation: 9,500
Aspect: N
Coordinates: 45.3810, -110.9610
Caught: 0 ; Buried: 0

From obs: "Skied Hyalite Peak today and found a wind slab ~10cm deep. Ski cut a small cornice below the main face and broke a small slide that carried ~20’ with little energy with a ~25’ wide crown"


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Bridger Range
Bradley Meadow
Wind Slab triggered on Bradley’s Meadow
Incident details include images
Bradley Meadow
HS-ASu-R1-D1-I
Elevation: 7,800
Aspect: E
Coordinates: 45.8322, -110.9280
Caught: 0 ; Buried: 0

"... a small wind slab avalanche (R1 D1)  from yesterday at approximately 7800 feet on the northern end of bradleys meadow. The slide was initiated by the second skier and although the rest of the slope was <30 degrees the starting zone was a NE facing steep cross loaded wind pillow just below the ridge. 

As my friend was skiing down he saw a crack propagate up and to his left and was able to stop on the side of the path as the snow ran past him. The  crown was approximately 30-40 feet and ran about 100 feet. 

Here are the coordinates of  a way point I dropped just above the top of the slide

45° 50.0218′ N, 110° 55.7420′ W

 we circled back and took a photo of the top as well...  "


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Bridger Range
Fairy Lake
Remote triggered wind slab N. Bridgers
Incident details include images
Fairy Lake
ASr-R2-D1-I
Elevation: 8,700
Aspect: E
Coordinates: 45.9043, -110.9580
Caught: 0 ; Buried: 0

From IG: "Remotely skier trigger wind slab up on white worm near sac bowl".


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Northern Gallatin
Mt Blackmore
Remote trigger on Blackmore
Incident details include images
Mt Blackmore
HS-ASr-R1-D2-I
Elevation: 9,800
Aspect: E
Coordinates: 45.4444, -111.0040
Caught: 0 ; Buried: 0

A skier remotely triggered an avalanche on Mt Blackmore (11/9/22).

From email: "I ski cut the top of the face and remote triggered a hard slab from 50’ above the crown. It broke full width of the couloir feature, 150’ wide and 10-18” deep. Broke on new snow/old snow interface which was another hard wind slab. The avalanche ran the length of the East face and stopped just below the last set of cliffs."

 


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Bridger Range
Bridger Bowl
Storm slabs at Bridger Bowl
Incident details include images
Bridger Bowl
SS-ASc-R2-D1-S
Elevation: 7,800
Aspect: NE
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0

From obs: "Saw some cracking and propagation of a 6-8" storm slab on steeper terrain near the Bridger Lift. Gentle upslope winds seem to have compacted a slab near some terrain features, and I got a small propagation at the edge of the Sluice Box gully where the slope angle tipped up near 40."


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Bridger Range
Bridger Bowl
Small Avalanche in Bridger Bowl
Incident details include images
Bridger Bowl
SS-AS-R1-D1-I
Elevation: 7,600
Aspect: NE
Coordinates: 45.8170, -110.9240
Caught: 0 ; Buried: 0

Small slab avalanche triggered by skier in a small chute near The John and Bronco runs in Bridger Bowl. Propagation from skier’s ski, slab slid down through the chute. Crown maybe 10 feet wide. Slab looked about 6 or 7 inches thick. Looked like a layer of new snow from today and yesterday’s storm sliding on top of an old crust layer. Nobody harmed, just spooked. Watch out!


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Bridger Range
Hardscrabble Peak
Avalanche in October Bowl
Incident details include images
Hardscrabble Peak
U-N-R2-D2
Elevation: 9,005
Aspect: NE
Coordinates: 45.9097, -110.9800
Caught: 0 ; Buried: 0

While traveling up the Fairy Lake road, we observed the aftermath of an avalanche in October Bowl. The avalanche was D2-D3, start zone was at approximately 9000 ft, north east aspect, crown depth and width is unknown.


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Bridger Range
Bridger Bowl
Micro wind slabs
Bridger Bowl
SS-N-R1-D1
Elevation: 8,000
Aspect: E
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0

BB skiing in the past few days. Pretty impressive single-storm coverage. Skied from the top of the nose down to the base on Wednesday. Spotted a few micro wind slabs that had peeled during the storm but nothing large.


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Northern Madison
Big Sky Resort
Natural Avalanche at Big Sky Resort
Big Sky Resort
SS-N-R2-D2.5
Aspect: NE
Coordinates: 45.2760, -111.4360
Caught: 0 ; Buried: 0

Big Sky Ski Patrol saw evidence of a natural avalanche in the closed ski area. 

From email: "saw evidence of a large avalanche that ran in 3 Forks area of The Headwaters... NE aspect in the probable start zone (could not see a crown) that likely saw significant wind loading Monday.  It ran full track and broke some branches and small trees in the runout. 

That was the only activity I saw (3 Forks is an avalanche factory with large storms).  Definite wind effect across the alpine."


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Bridger Range
Saddle Peak
Point Release on South of Saddle Peak
Saddle Peak
L-S
Elevation: 7,800
Aspect: E
Coordinates: 45.7943, -110.9360
Caught: 0 ; Buried: 0

A group skiing at Bridger Bowl observed at least one point release south of Saddle Peak above a cliff band. It appeared to be due to warming surface snow from the sun. 


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Bridger Range
Bridger Bowl
Avalanche Out of Hidden Gully
Bridger Bowl
Elevation: 8,500
Aspect: NE
Coordinates: 45.8156, -110.9230
Caught: 0 ; Buried: 0

A group saw debris from an avalanche coming out of Hidden Gulley and down into the Apron at Bridger Bowl. Bridger Bowl is closed and there is no avalanche mitigation or ski patrol activity. 


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Northern Madison
Beehive Basin
Avalanche seen from road near Beehive Basin
Beehive Basin
Coordinates: 45.3296, -111.3850
Caught: 0 ; Buried: 0

Skiers driving to Beehive Basin observed an avalanche from the road in the area. Minimal details

 

 


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