Snow Observations List

Wind was rocking in alpine today, fresh windslabs forming and naturally releasing. I could make out 3 on E face, but rough vis with blowing snow. Exposed terrain in alpine had about .5” ice crust from yesterday’s sunshine.

This slab (in pic) released around 11-noon-ish. 

Toured out of Pine Creek yesterday and up to around 9000ft. We found large surface hoar crystals around the creek and smaller NSF in most covered areas. In steeper, north-facing terrain, we found a fairly uniform snowpack in areas that had been seeing some wind and surprisingly good surface conditions for skiing. We found a few feet of sugar snow near the ridge line with large faceted crystals lower in the snowpack, restricted to mostly sheltered areas. While traveling, we saw no signs of instability except some wet slides from the past few warm days. However, the snowpack around Pine Creek is much thinner than the rest of the forecast area and is showing significantly more signs of faceting, especially in sheltered areas.

Went out to ski the S facing coulior on Mt Delano yesterday in the Absarokas and figured we’d report back.

In the valleys we found significant surface hoar. Once in higher elevation, widespread crust on all aspects.
On N facings- some wind blown snow above a 1-3 inch crust. Crust on SE-SW facing aspects varied from breakable to very firm. Facets under crust in some S facing areas as well.

Wet slide debris found on S facing slopes as per picture.

Overall a very shallow snowpack, including at almost 8k. It became a rock and downed tree avoidance mission.

Two Point release avalanches on south slope ofTwo Top

Saw this cool illustration of wind deposition, scouring and unaffected snow on a ridge line near the top of Bear Creek at the far end of Buck Ridge.  The lighting really helped too.  Ridge top is scoured and piled onto the lee slope and there is a very clear line between hard wind slab and relatively unaffected snow where the old snowmobile tracks are.  

We also spotted a small, snowmobile triggered avalanche on a steep, east facing slope in Muddy Creek.  

Today, we toured south of Cooke City, up Republic Creek and Republic Mountain. We spotted widespread, weakening snow surfaces: surface hoar feathers at lower elevations, faceted snow on cold, shady slopes up high, and faceted snow beneath crusts on solar aspects. Our pit on an E aspect at 9460' did not produce unstable test results, but showed the top 1.5' of snow to have faceted and weakened during this bout of high pressure. These layers are not concerning now, but will certainly be top of mind when the next storm system arrives over the weekend. 

We spotted several loose wet avalanches that occurred yesterday in steep, rocky terrain up Sheep Creek. We also noted an old, deep persistent slab avalanche on a NW' aspect near the south end of the Republic Creek drainage. This likely broke around a week ago. 

Skies were clear, winds were calm, and temperatures were warm in the sun and chilly everywhere else. 

From email: "Today I drove down Taylor fork road, with the thought of potentially getting up on woodward mtn, until I saw a crown on the NE
Face of its northern summit, basically wall to wall near the top of  the slide path. There were a couple other sled tracks that also went to the end of the road, so I figured maybe it was pretty recent, as I didn’t hear about it in the advisory. Concerning because it appears to have propagated maybe 250ft across,  while maybe only 1-2 ft deep" 

We toured Beehive Basin up to the prayer flags and dropped into Bear Basin. We dug one full pit in the starting zone of Tyler's (1m of snow, ECTP28 on basal facets - rough/non-planar fracture) but were primarily looking at surface conditions. 

The surface evolved throughout the day, so we must continue tracking its progression. We found surface hoar in the valley of Beehive, where inverted temperatures were the coldest, crusts with near-surface facets below, and some straight near-surface facet—recycled powder, along with thicker crust and wet snow. 

The warmer temperatures at higher elevations that came with the inversion are saving us from worse faceting. When we returned to the vehicle, the surface hoar had burned off in the warming temperatures, and others were moist. 

Surface conditions will continue to evolve but probably won't get stronger in the coming days. The good news is that the surface is holding up better than I expected. 

Wide spread layer of Surface Hoar mid and upper elevations Two Top area

Large surface hoar across a variety of elevations and aspects at Lick Creek. It was 2-5mm large and present on almost all flats and non-solar aspects, and from the road up to 8500 ft and above. The most recent snow was wetting out on the solars, and temperatures were well above freezing at my car when I got back to it in the early afternoon.

Toured up Ellis. Observed well-preserved surface hoar in meadows and on the ridgeline on NE aspects. MF crust starting to form on SE aspects. Dug at 8230’ on an ESE aspect. HS 120. Found the buried surface hoar layer from a few weeks ago down 25cm. Got collapsing but no propagation on this layer. Beautiful day!

Took the ridge out to Bridger Peak. Winds have done their damage and skiing conditions were quite bad. Winds had affected snow at nearly all elevations.

Snow depths on SE and NE aspects were 120 cm, and the snowpack is dense, hard, solid, and stable. We couldn't find any evidence of near-surface facets from recent cold weather and clear days/nights. The combination of wind and warmth destroyed them if they existed. 

On south aspects, the snow had become wet, and we spotted a few rollerballs/pinwheels - mostly near exposed rocks.

Drove up the road to the summit of Sawtell Peak for some weather station maintenance (it's back up and fully operational!). 

Had good views into the Centennial Mountains from the summit (Mt Jeffferson, Reas Peak, head of Yale Creek) and saw no signs of avalanche activity. 

The top inch of the snowpack was moist on south facing slopes at 9800 ft around noon and there was water running out of the cutbank onto the road. A few roller balls were visible, but didn't see any other wet loose activity. 

Recent avalanches noted on the NE-E aprons on cedar mountain. SS-N-R2-3-D2-I These appeared to have possibly happened during the last storm cycle and looked to be isolated to layers within the new old snow interface. I also noted similar activity on the same aspects on the adjacent ridge during our approach.  

Pretty widespread surface hoar this morning near Hyalite Reservoir. It didn't seem to be as widespread higher up on Mt Blackmore, but we did see some pockets of it up there.

From IG Message: Wind slab avalanche on “east facing slope in hyalite”

Widespread SH had formed over the past couple of days in areas on the approach that were out in the open but shaded from the wind. We observed cornices in the back of the basin (NE/E facing) and a small wind slab had broken off underneath them. Wind-blown snow had filled in the skin track and ski lines from yesterday in maiden bowl. The sun was baking the southern facing slopes for most of the day today, and when we skied out, the snow in the direct sunlight was wet. 

We skied up west Woody Ridge and skied down into Hayden Creek about 500 feet, then back up and over, and out Republic Creek.

Skies were clear with calm winds and a light breeze at the ridgetop. Temperatures were still mostly cold, single digits down low and teens up high in the morning. The sun felt hot mid-day, snow bombs were falling off trees and there were some small rollerballs around steep rocks on southerly facing slopes.

We saw one old, but very large persistent slab avalanche further up Republic Creek (pictured). It was on similar aspect and elevation as a somewhat more recent persistent slab in nearby Hayden Creek, North-northeast, 10,000'. It appeared to be 6'+ deep and 500'+ wide. The bed surface and crown had been partially drifted in, so it seemed it was probably at least a week old...?

There was also a recent cornice fall on a very big steep slope up Republic Creek (picture) which did not trigger anything large or deeper, but entrained some snow and ran over a thousand feet vertical.

We dug a pit at 9,900' on a west aspect. Snow depth was 150cm (5 feet). We had an ECTN11 below 3 inches of snow on top of small sugary facets near the surface. There were soft (4f+) sugary facets at the bottom of the snowpack, but they did not break in an ECT or with extra force. Snow depth above 9,000' was ~4 feet average based on a few places we probed as we toured up.

There were signs of a lot of previous wind up high. It has been a few days without wind, but there are probably some isolated instabilities of small stiff wind slabs sitting on facets which could be triggered.

We triggered a small soft slab avalanche when skinning near the top of Pair Of Chutes in the Playground. The slab was about 1 foot thick, fist hardness, propagated 20 feet wide and ran 50 feet before breaking up and arresting. The slab did not entrain additional snow as it slid. The avalanche hit my feet but did not disturb my balance. However, it could have been dangerous above consequential terrain. Moderate gusting to high winds were sustained the entire day and wind slabs were widespread in the backcountry terrain north of Bridger.