Snow Observations List

Via IG Comment:

Since Buttermilk is closed for the season we decided to park in town and ride for 20 min. Dave had a large collapse that he heard and felt in a meadow at 8,200 feet. On a NE facing slope off Lionhead Ridge we found 135 cm of snow which was basically 2 layers: 1.5’ of facets capped by a 2.5’ wind slab. It broke with a ECTP26. Structure was not great, and coupled with the whumpf we would not feel comfortable getting into avalanche terrain.

Paraphrasing from a text from Six Points Avalanche Education: 

We dug in the 2nd Yellow Mule. Wind slabs were the primary problem and we were getting consistent ECTPs in the mid 20's on wind-loaded slopes. If the slope did not have a wind load, the slab was missing. 

We toured up Bacon Rind to the meadow just south of the skillet. We got a whumpf within 5 minutes of leaving the car and another 5 throughout the day. This told us that the snowpack was unstable and would have kept us out of avalanche terrain regardless of our snowpack test results.Snowpack was generally 3-4 ft deep with ~18 inches of facets at the ground. Dug right where we left the valley floor at the site of our first whumpf (7,100 ft, S aspect) and again again at the top of the main meadow (8800 ft, E aspect). 3 ft of snow in both pits. ECPT18 & ECTP17 on 2 mm fist hardness facets in both pits. This weak snow is unfortunately going to be a problem for quite a while.

Sw aspect 

7900ft

70cm snow depth 

Failure/propagation at 20 cm upon isolation in both CT and ECT on facets at the ground

We skinned up to Mt. Ellis summit today. We dug our first pit on the approach at 7,700’. The first pit on a NE aspect was thin (HS = 80 cm/2.5 ft) with an ECTN 11 and 22 in the top half of the snowpack. In this shallow snow we saw depth hoar and facets at the ground. We dug our second pit near the Burn below the summit of Mt. Ellis (8,100’). This NE aspect had 2-3 ft of snow (85 cm), and we had an ECTX.

Both pits showed a shallow snowpack with facets at the bottom. Moving forward, the thin snowpack will be more susceptible to faceting. Also, the poor structure of this snowpack (dense snow on top of facets) could be a concern with more snow. These two things show us that we should continue to assess the snowpack around Mt. Ellis.

We hiked the ridge to Football Field. We dug just below the ridge and found a couple of problems in our pit. A 15-20 cm (6-8”) wind slab had formed over the last few days. The HS was 110 cm, and we got an ECTP12, below that wind drifted snow (11 cm down from surface). Next, we got an ECTP 21 and 28 in the middle of the snowpack (56 cm down from surface). The ECTP21 and 28 occurred on 1-2 mm facets sitting below a pencil hard layer of rounded grains.

Large slough or slide in Hyalite today. Taken from Lick Creek. Looks like either land of the lost or avalanche gulch

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.