Snow Observations List

Skied south of Cooke over the weekend. Winds were L-M gusting to X out of the W, SW. 19" HN at 8500' from Friday night to Sunday afternoon. Small, localized cracking of wind slabs, but they weren't as reactive as I would have expected. No avalanches seen, although visibility was limited. There are some density changes within the storm snow, including a layer of graupel. Storm snow was not reactive in hand pits. On solar aspects, there is a MF crust under the recent storm snow and facets under the crust. The crust varies in thickness depending on aspect and elevation, 1-3cm.

Good mellow dust on crust skiing with 1”-3” of poorly bonded new snow. Widespread shooting cracks observed on new snow interface on all aspects traveled through the day (primarily E and S facing aspects). Lots of wind transport filling in the skin track between laps and creating light reactive slabs ~5” deep in places (see photo) primarily out of the west but generally inconsistent in direction. 

See attached profile and photos.

Buried SH below the 2/1 storm. 1-2cm thick layer buried approximately 20cm deep below F precip particles. Surface snow had some graupel particles in it as well.

Human triggered release of cornice overhang near the weather station on Buck Ridge. Recent activity next to the small release. Crown 1-2’ deep, 40’ run, 75’ across running over the tracks riding underneath in the recent wind transported slab.

Skied north of Cooke City. Lots of cracking and small slabs on pillows. Observed one small wind slab on NW facing slope 9200 ft.

Cracking and isolated pockets of wind slab in Beehive. 

Skied into South Cottonwood basin from Blackmore today. Skiing was sub-par with lots of wind scouring and intense active snow transport. Along with the slides observed yesterday, two recent R1-D1 slides were observed in South Cottonwood Basin: below the Dogleg and on N Twin's west wall via cornice break. No surface hoar, slides from today, or cracking/collapsing were observed. 

Observed a large wet loose (D1) in Zimmer Creek today off SE facing cliffs. Likely happened 1/29. There were also other smaller wet loose avalanches nearby on south facing cliffs 

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!