Snow Observations List

No unstable results in 12 pits, dug on E-SE and W aspects at 8600’. HS 125-140cm. Light to moderate winds out of the S, with strong ridge top winds overnight. No cracking, collapsing, or other signs of instability. S-1 throughout day.

My partner and I snowmobiled into the Taylor fork up to the base of Shedhorn Mountain where we began ascending the E aspect on skis. On the way up,  SW winds were gusting in the moderate range  and there was active wind loading visible on the ridgeline. We chose to make our way up one of the main avalanche paths and observed a definitive faceted weak layer below more recent new snow. In November, I had observed this weak layer while it was forming, so I was not surprised to find it.

On a due east aspect at 8972', we chose to dig a quick test pit in lower angle terrain before traveling higher on the slope and exposing ourselves to the steeper avalanche terrain above that had evidence of somewhat recent D1-1.5 avalanches. Our pit showed a snow depth of 80cm and a definitive weak layer below recent new snow. Our results were encouraging, ECTN16, and we skinned up to treeline and skied the lower angle slopes below.  

We took our Avalanche Awareness class up to Bradley today.  We ascended up the southern flank of the meadow, and at about 100' below the top, we headed south just adjacent to the main meadow (lat. long. coordinates provided are at pit location).  We fanned out and dug 5 pits.  Four of them had an HS of roughly 60-65 cm, consisting of F storm snow with 4F below, the ocassional zipper crust, and then a bottom 15 cm or so of basal facets. ECTX in all of those pits.  

For the other pit, we seeked out a wind loaded area adjacent to the other pits.

Elevation 7751',  aspect 92 degrees, slope angle - 18 degrees, 

HS 110 cm

0-40 cm 4F to 1F

40-80 cm 1F+ to P

80-110 cm 4F Facets

ECTP21 at about 100-105 cm, just above ground within the basal facets

This result was in a very isolated piece of terrain.  Stomping around on the wind drift adjacent to the pit location, we saw no shooting cracks nor did we experience any collapses. The stout slab seemed to be keeping us from impacting the week layer until we isolated a column and banged on it with the shovel. It was quite the collapse when the crack propagated in the pit and the slab was thick, hard, and heavy to lift. It makes me curious of how this snowpack structure will respond if/when we put a significant snow load on it.

Just one result, but an interesting one.

Went on a tour today with some buddies with hopes of skiing the great one. Once up in the sac bowl, we opted to back away given the wind was howling. We skied the white worm, and saw numerous cracks shooting across the slope. I opted to ski a short and sweet N facing couloir which started out pretty firm into avalanche bowl. About halfway down, I had a wind slab release after one soft turn with the deepest portion of the slide being one foot. I was not carried as I immediately cut out of the fall line, the slide rolled for about 200 vert. My friends opted to ski the direct headwall exit and had numerous small wind slabs pull out. Some areas were stripped to rock of snow. 

ECTP25Q1 on a layer of well developed facets about 30cm from the ground on an easterly aspect at 9200 feet. Pit was approx 75cm deep.

Observed heavy active wind transport from westerly aspects to easterly aspects.

Larger, 1.5-2mm facets were found in our westerly pit at 9100 feet but not reactive in tests. It was enough for us to not consider descending avalanche terrain. 

My partner and I dug a pit at 8553ft on a SW aspect in the sheep creek drainage outside of Cooke City. Our results were an ECTp13 Q3 @35cm. Our pit was 80cm deep. Layers we found from the top down in our pit:

• 80cm-50cm fist hard
• 50cm-43cm 4 finger
• 43cm-39cm 1 finger
• 39cm-ground fist hard

We also experienced whumphing on our tour which made us dig down and see what was going on in the snow. 

Cornice dropped in Slats and propagated slab at a weak layer of facets around 70cm height from ground. Dug a snow pit of 140cm and got etc results on the same layer ECTP26 stubborn but holds a large consequence.

Snowed hard all day. Lots of new snow (18” in the past 24 hours at upper elevations at 4 pm). Found 4 ft deep fresh wind drifts near the summit of Sawtelle Peak while going to work on our weather station. 

Rode into Yale Creek and dug on a south facing slope at 8000 ft. HS was 133 cm. Found 2 mm facets 40 cm off the ground (similar to what we’ve been seeing in the Lionhead area). Interesting to note that on this lower elevation sunny slope there was a melt-freeze crust above the facets and percolation columns running down into the facets. ECTP25 on the facet layer. As we rode to the head of Yale Creek the new snow kept getting deeper until there was ~18” of new snow where we dug again at 9000 ft on a NE aspect. HS was 235. ECTP8 and ECTP9 within and at the bottom of the new snow. Lower snowpack looked pretty decent and there wasn't a dramatic faceted layer. Rounded facets in the bottom meter, but 1 Finger hardness and no results in the ECT. 

All this new snow and wind drifting makes for unstable conditions. More snow this weekend will make the avalanche conditions even more dangerous. Finding weak layers in the snowpack means that avalanches could break deeper, could be triggered from below, or could be triggered after multiple people have ridden the slope. 

We recommend avoiding steep terrain and the runout zones below steep slopes for now.

I dug a pit above Silken Falls in the gulley. I found a weak layer of facets breaking about 10" under a wind slab (ECTP15). We did not get any cracking, but the terrain is very serious and even a small slide could be deadly. We did not feel comfortable center punching up the gully. Given how much traffic the gullies are getting, I do not think it is widespread, but it's out there and could avalanche.

Wind and snow this weekend may make this layer more unstable, so it's important to be careful crossing exposed terrain. Either rope up or tun around if it is suspect.

Got in my first tour of the year on Mt Ellis today! I dug a pit on an E/NE aspect at about 7650', and found 90cm of snow. I could not get anything to pop in a shear test, and an extended column had no result. The snowpack very gradually gained density from fist to 1F in about as nice of a gradient as I could hope to see. There was a ~5cm layer of slightly less dense 1-1.5mm facets right at the ground, but they were surprisingly moist and packable. When I finished my ECT, I pried at the back of the column and the whole thing tipped over, taking some dirt with it. This is my singular data point for the year, but my assessment of this small area is that the snowpack is fairly weak, but unstressed where there isn't any wind loading. 

Small slide from the cliff bands at about 9500’, on a NE facing slope on Blackmore - looked like it broke pretty shallow sometime after the snow yesterday.

We toured and skied on the Throne today.  Ended up being a one and done as the snow depth there still isn't deep enough to cover hazards, we hit a lot of rocks.  This was our second attempt here, tried on Nov 17th and thought there would be enough snow by now but it seems strong winds have been stripping this area of snow as compared to Bridge Bowl for example.  Snow depth on the east aspects of the Throne was highly variable but most of the coverage was on the order of 12"-16" deep.  East aspects varied from breakable wind crust to some supportable snow/crust with F hardness wind affected snow on top.  The winds must have been pretty consistent, even the tree protected north facing lower elevations of the Throne were wind affected. The entire southern aspect of Naya Nuki also looked very wind stripped with large bare spot visible at mid elevation.  The upper elevation east facing aspects above the Throne were also very wind affected.  We dug a pit about 75' below the high point of the Throne and then skied the north facing gully back to the North Fork Brackett Creek drainage.  Included a map pic to show were the pit was located.

ECT Results

12/8/2022 11:50am

HS: 80cm (this area was wind loaded, 200' away in the gully the snow was 30-60cm deep)

Air temp: 20F  Sky Cover: Clear  Precip: NO  Wind: Calm

Elevation: 8300       Location: N 45deg 52.9547min  W 110deg 57.1631min

Heading: 330

Slope Angle: 30deg

0-25cm - 1F, some faceting at this interface

25-65 - 4F, faceting at a snow interface layer at 55cm (possibly a decomposing suncrust?)

65-80 - F, wind deposited snow, not much cohesion

ECTN 21 at the 55cm layer, very rough failure plane, no propagation

ECTX on the remainder of the column

Comments:  The area is so variably covered right now that this test was mostly for curiosity sake and gave us confidence to ski the north gully (lots of sharky rocks) and call it a day.

Two small natural avalanches observed today from the YC. Both on likely wind loaded easterly aspects on slopes around Cedar Mountain at roughly 8,000’. 

We rode to Daisy Pass to look at the avalanche that was triggered by a snowmobiler two days ago (12/6/22). It was on the slope east of the pass that people often climb up and out, steeper than the normal route out. It broke 2-3 feet deep and 250-300’ wide, R2-D2. At the crown it broke on a weak layer about 100cm above the ground, but it broke closer to the ground in many places lower on the slope where the snowpack was shallower and weaker. I would guess one of those areas is where it was triggered from.

Next, we rode around the back of Fisher Peak to Lulu and dug on the southwest slope below the weather station. Here it was shallow, 100cm. There were weak facets near the surface, but no slab on top of them, maybe due to the southerly winds scouring it. Could become unstable if loaded from the north or with a lot of new snow. Finally, we rode up to the shoulder of Scotch Bonnet and dug on far south Rastas. HS was 145cm, we had ECTP22 and ECPT27 on a thin layer of facets sandwiched between two crusts 55cm off the ground. Despite the hard force, these collapsed dramatically and re-iterated the possibility of triggering a large, high-consequence avalanche.

There is windloading along the ridge line but the snow is pretty unaffected on the face. 

I dug 2 pits at different locations:

Pit #1: ECT N21 N28 

Pit #2: ECTX 

Both pits were on E slopes around 7,800 ft.  Overall feeling good with the snowpack there. It does have a slightly upside down structure but couldn’t get anything to fail.  

From IG: “Avalanche spotted on Henderson bench today, appears to be cornice triggered yesterday or the day before. 2-5 feet deep, 600’ wide, ran 800 vertical.”

We rode from Sage Creek trailhead to the weather station. After we got everything installed, we headed to Sunlight Basin to dig. There was about 12-15 cm of new and wind drifted snow. On the walk to the pit location we noticed the snow was punchy. HS was 94 cm on the E aspect. We got an ECTP 13 on a layer of 2 mm facets 44 cm down from the surface. New and wind drifted snow put a substantial slab on top of this weak layer. After we dug our pit visibility improved, and we saw a R1-D1 across the bowl that looked recent. While sledding around the area we noticed faceted snow in the middle of the snowpack in multiple locations.

Skied in NE Yellowstone Park today near Cooke City. No avalanche activity to report (low vis). Localized collapsing. No cracking.

We dug on a SE aspect at 8500'.

HS: 102 cm

ECTP25 @ 37 cm above ground.

Frequent shooting cracks, collapses, and whoomphs on wind drifted snow just north of town on a south facing aspect at 8,100ft.

We skinned into the Divide Peak cirque to check out the conditions in Hyalite for the first time this season. On our tour we saw a couple of small R1-D1 slides that had broken within the new snow. At our first pit we saw HS at 124 cm with 10 cm of new snow. We had a ECTP 30 on facets 64 cm down from the surface. Next we dug on a SE aspect with a HS of 127 cm and 15 cm of new snow. We got an ECTN-3 within the new and old snow. More importantly, the wind was picking up throughout the day, and it was transporting snow. Our primary concern today was new snow, and in the next few days it will be wind drifted snow.