Snow Observations List

GNFAC
Northern Gallatin
Maid of the Mist
Watch out for the Wind Drift
Snow Obsdrvation includes images
Snow Obs contain video

There was 9” of new snow at higher elevations compared to 4” at the parking lot, and what was accurately reported at Shower Falls SNOTEL. We saw strong winds blowing huge plumes of snow off Maid of the Mist proper. Spindrift and wind-loading into gullies, near ridgelines and other slopes exposed to the wind was our primary concern. We dug two snowpits, one in the Basin low on a north facing slope and another on the south-facing shoulder. We got ECTNs in both. We found the 2-3" thick layer of facets and surface hoar on the south-facing pit buried 3' deep. They propagated failure with a few extra hits in our ECT. They weren't sensitive where we dug today, but I would not forget about them. 

We avoided wind-loaded slopes entirely and would recommend digging down three to four feet to test the upper level of the snowpack before considering any steep slopes. 

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High Mtn Adv
Lionhead Range
Two Top
Sledder triggered slide, Two Top

From FB: Had some tourists in the shop trigger an avalanche on two top yesterday. Didn't get exactly where or much details. Steep tracked up slope they set off. Just a partial sled burial.

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J. Lipkowitz
Southern Madison
Ernie Miller Ridge
Wind slab over facets

We toured up to the bacon rind ridge, descended a southwest aspect, and then headed over and up to the Ernie Miller Ridge.

In sheltered locations, there was approximately 15 cm of storm snow from Sunday into Monday.  

On an east-southeast aspect off of Ernie Miller between approximately 9000-9700', we found widespread 20-25 cm thick 1F wind slab sitting on 1 mm facets. The slab was moderately resistant in hand shears and remained intact once isolated. It was not reactive to our jumping on small test slopes. We observed no cracking during our ascent and saw no signs of reactivity during our descent.

Above approximately 9700', the surface was largely scoured and there was a thin wind skin.  

We observed similar facets below the storm snow on our ascent of a southwest aspect between 8000-8700' on the way back up to the bacon rind ridge.   

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GNFAC
Island Park
Mt Jefferson Bowl
Remotely triggered an avalanche, Mt. Jefferson
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We rode up Yale Creek and into Mt Jefferson Bowl. Walking to the edge we triggered an avalanche (intentional) on a slope that was getting wind-loaded. It broke up to 1.5 feet deep, 250 feet wide and 50 feet vertical. The new wind drifts were sensitive to triggering and the slabs propagated wide. Weak layers at the old snow surface may have helped us remotely trigger the slope. The two things to look out for in the Centennials are weak layer of sugary snow or feathery surface hoar in the upper 3 feet of the snowpack and slopes that are freshly wind-loaded.

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S. McCaffrey
Bridger Range
BRIDGER RANGE
Avalanches on Bridger Canyon drive
Snow Obsdrvation includes images

One maybe two distinct seemingly natural large natural slab avalanches on small slope directly next to bridger canyon drive.  One on the lookers left was likely cornice triggered, but on the right it's unclear to me if it propagated or released naturally.

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Anonymous
Out of Advisory Area
Slide into Cliff Lake
Snow Obsdrvation includes images

A slide occured at cliff lake up the  North Meadow area. I realized it had blown half way out into the lake. Looked like 48 to 72 hours ago but ice had been comprimised pushing chunks up.

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B. Morgan
Southern Madison
Sage Peak
Natural Avalanche on Sage Peak

From FB: We saw a fresh break on the west face of sage peak last night, I would guess around 9500’.

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GNFAC
Cooke City
Sheep Mountain
New snow and small rider triggered slide
Snow Obsdrvation includes images

We rode north of Round Lake this morning (2/6/23). Near Long lake we measured 9" of new snow = 0.55" snow water equivalent. Near the Goose Lake wilderness boundary we measured 10" new snow = 0.65" SWE. In places there were 1mm facets below the new snow.

Wind was moderate-strong at the ridgelines, but calm around the lakes. 

There was a small snowmobiler triggered slide on a convex bench between Sheep Mtn. and Round Lake that was triggered this afternoon. It was 1.5-2' deep, 30' wide, and looked to have broke on a weak layer below last week's snow, on a freshly wind-loaded slope. In a relatively shallow, rocky area (photo attached).

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GNFAC
Island Park
Yale Creek
Finding weak layers in Island Park
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We rode up Yale Creek to across from Arange Peak, then back into Yale Creek. We dug 3 snowpits looking for weak layers and found them a foot or two under the surface. Feathery surface hoar mixed with small, sugary facets were found in all. This layer was not propagating in our tests, but we know that nearby in Lionhead they avalanched. We are not completely trusting of these layers, especially at higher elevations where wind drifts would be adding even more weight to these layers.

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GNFAC
Cooke City
Scotch Bonnet
Weak facets buried, and new snow
Snow Obs contain video

This afternoon (2/5/23), we rode over Daisy Pass in hopes of seeing the recent skier triggered slide on Fisher Mountain, but it had started snowing and visibility was too limited to see the crown or get to the slide. We rode around the back of Fisher to Lulu Pass and then up to the south shoulder of Scotch Bonnet to dig a pit. There was an old, large pile of debris at the bottom of one of the Rasta Chutes that I assume slid last weekend.

We dug a pit at 9,600' on a southwest facing slope. HS was 160cm. Below last weekend's snow (1 foot/30cm deep) was a 10 cm thick layer of soft facets (F+ hardness). We had an ECTN 21 and ECTP 21 on this layer. The recent skier triggered avalanche on Fisher probably broke on this layer, on a more wind-loaded slope. This layer will be a problem for a while, especially as it gets loaded by more new and wind-drifted snow.

Wind was moderate out of the southwest-west, and at 4pm there was 3" of low-density new snow.

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C. Pruden
Bridger Range
Pits at the top of Texas meadows

ECTPX in two pits at the top of Texas Meadows. No active wind loading. 

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B. Dallas
Northern Gallatin
Flanders Creek
Recent avalanche activity
Snow Obsdrvation includes images

We observed some crowns from recent slides just south of the Flanders Peak east glade while touring up Flanders today. The snow was wind affected and slabby especially towards the ridges. No other signs of instability observed. We opted to stay in the trees and minimize exposure on the ski descent.

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Anonymous
Northern Gallatin
Hyalite - main fork
Reactive wind slabs in Hyalite

Heading up the Genesis gully towards Zack Attack on 2/5, we turned around after finding multiple very reactive slabs. The first slab broke very easily, ~4 hits from the wrist, and had a very clean shear ~4in deep. The second slab was more difficult to trigger and did not have a clean shear, but was maybe ~1.5-2ft deep.

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C. Fueg
Northern Gallatin
Hyalite Peak
Avalanche on Hyalite Peak
Snow Obsdrvation includes images

Me and a buddy were out skiing/camping in the Hyalite Lake area. Late Saturday afternoon we started skinning up towards Hyalite Peak. The path up to the ridge was super hardpacked and windswept. We got up and there was quite a bit of snow loaded above the north slope. I dropped over the side and took about two turns before the entire face above me released from the very top and traveled down the entire north side down to the bowl below. I was able to get to the rocks on the side and my partner was able to pick his way down. The crown looked a few feet deep from what I could see and stretched across the entire top of the line.

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GNFAC
Northern Madison
Beehive Basin
Buried surface hoar in Beehive
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Snow Obs contain video

We toured up the ridge between Going Home Chute and Tyler's (below prayer flags). We saw evidence of a large avalanche that broke during the avalanche warning last weekend in Going Home Chute, R3-D2.5 (see photos). It appeared to have run to the end of the runout zone and tipped over small trees. We dug a pit near the top of our ascent on a west aspect at 9,100'. HS was 160cm and we found surface hoar buried 55cm deep (105cm above ground). It did not propagate or easily break in our tests, but it was a clear stripe in the wall and may have contributed to the adjacent large avalanche last weekend.

We dug a second pit over the ridge in Middle Basin on an east aspect at 9,200'. HS was 175cm and buried surface hoar was 80 cm deep (95cm above ground). It did not break or propagate in standard ECT, but did propagate cleanly after 4-5 extra hard hits. Old faceted layers deeper in the snowpack were generally strong in both pits.

We also saw a crown of a large avalanche from earlier in the week on the west side of Beehive Basin, on an east facing slope around 8,800'. R3-D2, 2-3 feet deep, 150' wide.

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G. brogan
Northern Gallatin
Mt Ellis
Mt Ellis report

Skied Mt Ellis today. The burn was heavily wind loaded at the very top but softened significantly as you got lower on the slope. I got an ECTX in my pit, the snowpack seems to be adjusting well to the recent load in this area. There were still multiple layers of concern that would give me pause to step out into bigger terrain throughout the advisory area. 

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A. Alloway
Northern Madison
Deer Creek
Deer Creek Sat Feb 4th

Toured/ skied on S though E aspects between 6000' and 8200' and observed the following:

-No slab avalanches observed

-Several localized whumphs 

-Two hand shears that failed upon isolation down 35cm, sudden planar failure (storm snow/ old snow interface)

-Two hand shears that failed easy down 35cm, sudden planar (storm snow/ old snow interface)

-Stomped one freshly wind-loaded rollover on micro-terrain and released a small (15 cm - 30cm thick) windslab

Dug a quick pit on an E aspect at 8200' and observed the following:

-HS 120 cm

-ski penetration 22cm

-boot penetration 53cm

-CT 17 resistant planar down 35 cm (storm snow/ old snow interface)

-ECTP 14 down 35 cm (storm snow/ old snow interface)

Steady, moderate winds all day from SW and W; no blowing or drifting snow observed in our immediate vicinity

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Anonymous
Northern Madison
Buck Ridge
Snowmobiler triggered on Buck Ridge
Snow Obs contain video

From FB message: I triggered this one Thursday night (2/2/23). Got lucky it didn't gain speed and sack on itself. Been in this zone 1000 times, never seen it slide, always gotta be on your game... NE aspect in Beaver Creek.

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E. Heiman
Northern Madison
Beehive Basin
Signs of Instability in Beehive Basin Area

Our group toured up into Beehive Basin yesterday with the goal of skiing Peru and returning via Middle Basin. Our ascents and descents on the day showed signs of small pockets of wind slab instability (cracking and small pockets pulling loose), but nothing significant. On our final ascent up the backside of middle peak, there was a large shooting crack, maybe 30 feet in length, but we adapted our ascent route and were able to avoid further significant instabilities. Hand pits showed a thin 2" wind slab on our final ascent slope. Throughout the day we noticed a few old crown lines varying from 1 to 2' in depth and up to about 150' wide. These crown lines were on E, NE, NW and W aspects. The debris appeared to not be recent as it was covered with new snow and eroded, and some of the crown lines were filling in. 

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BSSP
Northern Madison
Lone Mountain
Skier triggered slide in Lone Mountain backcountry

A 2’ storm snow avalanche in the Chippewa Notch area was apparently triggered by a rider. It propagated significantly across complex terrain, and ran through plenty of terrain traps/trauma trees.

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