Snow Observations List

Signs of Unstable Snow

Recent Avalanches? 

 None Observed 

Cracking? 

 None Experienced 

Collapsing? 

 None Experienced 

We observed a strong cohesive snowpack on a wind loaded slope NE of Two Top. But we noticed three separate buried SH layers. First 5cm from surface second @ 25cm third @55cm. These buried SH layers tend to be touchy. They are concerning in that the deeper layers rest above and below densely packed wind blown slab.

Three separate layers of Buried SH within the top 100cm of the snow pack. The top layer @5cm from the surface is not worrisome at this time but with added snow in the future it has potential to become a problem layer. The second and third layer @25cm,@55cm,from surface could be human triggered, with the potential of a deadly slab avalanche.

Advanced Information

Weather Summary

Cloud Cover:

Partly Cloudy 

Temperature:

17° 

Wind:

Light , SW 

New/Recent Snowfall:

No resent snow 

Upper elevations mostly sunny the past 2 days.Lower elevations experienced AM fog Light winds. We noticed ridge top blowing snow.

Advanced Information

Weather Summary

Cloud Cover:

Partly Cloudy 

Temperature:

17° 

Wind:

Light , SW 

New/Recent Snowfall:

Avalanche Observations

Avalanche Observation Comments:

Observed several natural avalanches on NE ridge at Two Top below cornice in steep wind loaded terrain

Snowpack Observations

NNE aspect 8186ft, 44.62319,-111.24732, HS230,PWL buried SH@ 5cm,25cm,55cm from surface. First test, CTMsc@55 second test CTMsc@25. ECTN27@25 

Layer Depth/Date: Jan.22,2023  
Weak Layer(s):  Jan 5, 2023 (SH) 
Comments: Buried SH 5,25, 55, CTMsc@55, CTMsc@25 ECTN 27@ 25

Buried layers of SH. These layer's seem to be very widespread throughout the region. They are worrisome in that they could be human triggerd with deadly potential.

Terrain Use

Our travel Plan to avoid any terrain greater than 30°. There are many options in this area to have a challenging ride without exposing the group to avalanche hazard.

Yesterday we toured around Mt Blackmore. We decided to make conservative choices and stay out of avalanche terrain and did not dig a full pit. Next to a meadow we did ski, on a northeast aspect above Blackmore lake, we did a quick ski cut on to a steeper slope. This cut readily released the new snow (~8in at this particular location) and it slid for about 50 feet on a 34 degree slope. This location did not present any signs of significant wind loading. The interface below the snow from the weekend will certainly be something to look out with more snow on the way.

We skied around Wolverine Bowl, the Playground, and Texas Meadows.There were 2-3” of new and wind drifted snow. The winds were gusting 15-20 mph and transporting the new snow. We dug in the Playground at 8,000’ on a N facing aspect, the new snow was moving on the old wind slab (ECTN 1), and the wind slab about 1 foot below the surface did not propagate (ECTN13). The unsupportable wind slab in the playground sent us over to Texas Meadows, and we dug at 7,800’ on the NE aspect. We did not see the wind slab here, and we got an ECTP 26 in the facets near the ground (3’ below the surface). It will take a lot more snow and wind to reactivate this layer. Looking forward to tomorrow the new and wind drifted snow is the biggest concern in the Bridgers--especially in complex avalanche terrain and along the ridgeline.

My ski partner and I dug a pit at the base of Divide peak on a SE facing slope at 9,600 ft. We had no failure in our compression test and an ECTX on our column test. The snowpack looked to be completely faceted yet consolidated from the ground to a crust layer just below the new soft snow. There was little evidence of wind loading in the basin and a layer of surface hoar was present on the snow surface. We passed another party who were digging multiple pits on a similar aspect and had the same results we found. We ran into a third party on the summit who dug a pit a few hundred feet from the summit that showed a slightly stiffer slab on the surface but again found stable results. This is still a tricky snowpack and this only shows that conditions were stable on this day at very specific locations. If you venture into Hyalite still do your homework before dropping in! 

Visible transport on with wind direction shifting from SW to NW in the afternoon. Dug at 7760' asp 85deg slope angle 20 deg on the South side of Bradley's. HS 180 ECTP10 down 25cm. 1F+ hard wind slab over F hardness snow. Slab was not consistent on that aspect at that elevation, we definitely hunted for potential reactivity with many handpits during an avalanche course. 

We skied down the "skyline" ridge of Saddle Peak. Recent strong winds drifted snow into small 4" soft slabs near the ridgelines, and there were a variety of new and old hard slabs and scoured surfaces throughout all elevations on the descent. We dug a pit around 9,000' and had an ECTP14 6-10" deep below a very hard slab sitting on sugary facets. We guess this is what the snowboarder triggered avalanche on Wednesday failed on, but that is just a guess. Due to the weak facets some of these hard slabs might be unstable for a few more days. Snow depth was 150-210cm where we dug. There is weak snow near the bottom of the snowpack that we need to remember for when there is heavier loading from snow and wind, but it seems unlikely it will cause an avalanche right now with little recent snowfall. 

Beartooth Powder Guides reported remote triggering a small wind slab on the SH layer and a small natural in the lower part of the Bowl that also likely slid on the fresh SH 40’ wide 4” thick. East aspect 9900’.

From Big Sky Ski Patrol 1/21/23: "skier triggered a surface wind slab in Wyoming Bowl that broke 8-12” deep. It propagated to an estimated 150’ wide- SS, R1/D1.5... The slide was small, no one was hurt, and the avalanche was reported (which we appreciate), with no further public involvement other than the trigger."

Went on a "loop de doop" type of tour yesterday to see conditions around Big Sky. While skiing a north aspect off Middle Peak, we dug a pit around 10k and found a hard 6 inch wind slab on the sitting on top of a firm column, ECTP16 on this top layer and it seemed like this was an isolated problem. We skied a SW aspect from the Bear/Hellroaring ridge and found great, consolidated snow from ridge to creek. We ascended and dug a pit on a NE aspect in Bear basin and found the depth hoar that everyones been talking about, we found this about 2 feet deep and had collapse but no propagation in our stability test. We skied a SW aspect back into Middle Basin in solar affected snow, a few ski cuts cleaned out the chute and the snow ran slow, but capable of taking someone off their feet. Multiple point and release wet snow activities were observed on all similar aspects off of the ridge. 

Observation Details

Observation Date:

January 21, 2023 - January 21, 2023 

Submitted:

January 21, 2023 

Observer:

RRS - Kevin Allred 

Zone or Region:

Island Park 

Location:

Yale Creek (SSW) 

Signs of Unstable Snow

Recent Avalanches? 

 None Observed 

Cracking? 

 None Experienced 

Collapsing? 

 None Experienced 

Found a layer of near surface facets 25 cm from the surface not problematic now but with new snow coming this could become a layer of concern 

Snow Stability

Stability Rating: 

Good 

Confidence in Rating: 

 Moderate 

Stability Trend: 

Steady 

Bottom Line

The snow seems to be very stable found a MF crust 45cm / surface from a warming trend early in January. Below the MF layer a strong cohesive slab. 15cm layer of DH at ground level average grain size of 2 mm 

Advanced Information

Weather Summary

Cloud Cover:

Clear 

Temperature:

17º 

Wind:

Calm , SW 

New/Recent Snowfall:

Trace of new snow past 24 hours 

Mostly clear skies light winds out of the south west no blowing snow 

Avalanche Observations

Avalanche Observation Comments:

None Observed

Snowpack Observations

Head of Yale Creek 8470' elevation SSW aspect HS 175 CTM SC @ 20 cm below surface on a near surface FC. ECTN 

Avalanche Problems

Our primary concern is a layer of SH that is variable in distribution . This layer was not evident in our snow pit location. 

Terrain Use

Our travel plan avoid avalanche terrain over 30° We traveled to observe an avalanche fatality site from 1998. The area had heavily trafficked by snowmobile activity. We remained with our conservative travel plan at 30°

Bad quality but a D2, R3 natural in Flanders cirque. Looked like it was just the new snow, but hard to say.... on a NW aspect around 9,500 feet

We are finding impressively strong snowpack. But we also have a weak layer buried about 2 feet into the snowpack that is very worrisome. It's deep enough that when triggered will be deadly, consider consequences and know where the persistent weak layer is before exposing your group. We have been on the snow all week and find lots of powder to play in without using slopes and connected terrain that is greater than 30 degrees.

SE aspect, 7640 ft, HS 130, PWL buried SH 83, DH 45, CTHsc@83, ECTN23@45. 

This PWL is widespread, but not necessarily reactive in all areas. We did feel a collapse on this same aspect and elevation yesterday, near Sawtelle Creek so we went back to test and found some results. 

On January 19 we rode north of Cooke City to dig in a variety of locations and look for the surface hoar layer that is buried 1-2 feet deep. Over the past week, forecasters and other groups have found unstable test scores on this layer, and there was at least one rider triggered avalanche and one natural avalanche that broke on this layer 3-5 days ago. These two known avalanches were on east to northeast aspects at 9,200-9,800'.

We dug five snowpits and performed extended column tests in each on 1/19/23 (I said "four pits" in the attached video, but I forgot to count one that was 15 feet away from another). Four snowpits were on northeast to north facing slopes between 9,200-10,000', and one pit was on a southwest facing slope at 9,200'. In one pit on a NE aspect at 9,200' we had an ECTP 15 on the surface hoar 35 cm below the surface. In all other pits we had ECTN14-19 at the depth of the surface hoar, and no obvious feathery crystals were visible. The layers where the ECTNs broke appeared to be decomposing, preserved dendrites or maybe decomposing surface hoar.

There was about 6" of low density snow that slowly accumulated over the last few days. Below and within this new snow are layers of near surface facets and surface hoar that formed during clear, cold nights. These may be future weak layers. There was almost no wind the last 3-4+ days, so this snow is still available to be drifted into thick slabs when the wind increases.

We stopped on a couple west facing slopes that were heavily wind-affected, and we sunk about 3 feet to the ground when we got off our sleds. These areas of shallow snow hold very weak, sugary facets that will be a problem if loaded with heavy snowfall. 

At the moment, the general snowpack stability is improving with an extended break from heavy snow or wind-loading. I suspect there are a few lingering pockets of unstable surface hoar that could be triggered, and there is plenty of weak snow near the surface. If the wind blows snow into thick drifts, or more snow falls than expected, stability could quickly become worse.

Photos of avalanches are those previously reported on Monday on Miller (photo taken 1/18) and Henderson (taken 1/17).

We were in the Beaverhead Mountains, mainly below Italian and Scott Peaks. We found various weak layers towards the top of the snowpack in places and in other places, completely bottomless pow approx 3+' deep. The weak layer areas the top 2" was breaking and sliding right around that 30 degree mark. We used Fatmap app to plan our route to the summit and worked our way around most 25-30 degree angles. Once we pushed that 30 degree angle that top 2" would release. In this area we observed the top 2" was hard like 1F or P hard, 4-5" of Fist or 4F, then another layer of 2" of P, and facets for about 20/30" to the ground. In the wind blown areas the top was almost solid, very hard and icy. 

Not good riding, but we did it.  

Observed this cornice fall triggered slide morning of 1/19/23. It was not there the previous morning which was sunny and clear. Photo: GNFAC

I dug one pit at 8200’ NE aspect in Yale ECTX. Kevin was a little lower and around on the east side of Sawtell, he felt a big wumph. He didn’t confirm what layer, but this is probably your buried SH.

Today we toured up Storm Castle Ridge with hopes of skiing the 19th Street Couloir. On the approach we were able to trigger small (2-4") wind slabs on most lee aspects, these slides ran fast and far for their size. We dug a pit at 9200' on a North aspect and we're able to identify the surface hoar but had no results on our ECT.  With 2 spotters I dug an ECT 10m below the top of the 19th Street Couloir and got and ECTP12@ 35cm below the surface. The slab was 35cm thick, pencil hardness and failed on faceted snow; the buried surface hoar found in most other pits was not present. We bailed to the opposite side of the ridge and enjoyed some wonderful burn skiing. 

Small avalanche broke while descending to less exposed areas.  Approximately 80 yards wide, 18” deep.  Slid for approximately 90 yards from crown.

A snowboarder triggered a shallow avalanche (estimated 4-6 inches deep) on Saddle Peak in the new snow. The slide was as the snowboarder dropped off "Quarter Saddle" and a second pocket propagated above him as he traversed out of the first slide. 

Another slide was seen from the highway in Argentina Bowl. This slide appears to be a shallow soft slab that ~50 ft wide and ran ~500 vertical ft.

From IG: Some people got something to run long off the south peak. People were center punching Argentina and north saddle without consequence, but the wind slabs were generally dense enough to propagate but not so dense that they weren’t easy to trigger.

From IG: Sent attached screenshot and video.