Snow Observations List

Around 7 p.m. Monday night, a few miles up Portal Creek, triggered from bottom of slope.

Small wind slab in hyalite at the start to champaign slot, 7600’, WNW, ~8” crown

We were ski touring on the SW side of Mt. Henderson today, and noticed a large (natural?) avalanche on the NE aspect of Henderson.  First observed at around 1:15pm.  It appeared to be very fresh, possibly from a remote trigger this morning.  

2 photos attached.   A NE aspect, around 10,000'.

It looked to be 4-6' deep and about 500' wide.  And it failed on snow at/ near the ground.

Weather:  today alternated between heavy snowfall, and patches of sunshine.  Temps in the low/ mid 20's F, and calm winds.  A very nice day for ski touring.

No other avalanche activity observed in Miller Creek.

We experienced a couple of large collapses on westerly aspects/ in wind affected terrain around 10,000'.

We toured into Carrot Basin and Sage Creek this morning. The storm ended and skies were broken by 1000. The spx is about 1M deep and the surface conditions are soft and excellent in most areas with wind effect along the ridges. At about 130 we moved from carrot to sage creek and notcied three small and one large avalanche along cabin creek divide that were not present earlier in the day. Most looked remote and were isolated pockets (R1/D1). As we rounded the corner into sage there was one fresh larger slide (R2/D2) at about 9,400' on a NE facing slope. It appeared to be natural (remote?), failed at the ground and was about 200' wide and ran for 200' the crown was 2-3' deep.

From email: "Skied in Sheep Creek today. Still a little lean. Surprised to only see one D1R1 soft Slab on steep north facing slope. No other avalanche activity seen on Miller Mountain, Mineral, Sunset and Republic Mountain. No cr/co." 

It was still snowing heavily when we arrived at the Beehive Basin trailhead this morning. We noted about 12-18" of new snow and winds blowing from the NE. It only took 20 minutes of skinning before we triggered a small avalanche in a terrain trap from a flat bench above. This slide (R3 D1) broke 150' wide, about a foot deep, and filled the creek bed below.

As we continued up the basin, we pulled off just south of Tyler's and dug a snowpit in a protected meadow at 8446'. Our snowpit (HS 130) gave us clear, unstable test results: ECTP 10 and 18. Propagation occurred at the storm snow interface (10) and on the faceted persistent weak layer close to the ground (18). Our snowpit was a great piece of data, but, after triggering an avalanche moments before, we had all the feedback we needed to stick to a conservative travel plan. We chose to stay in the basin and give a wide berth to slopes steeper than 30°. 

Once this period of active loading ends, the storm snow instability will settle out relatively soon. But we are not forgetting about the persistent weak layers that are still lurking at the base of our snowpack. 

I recieved a call from BBSP patrol director at 9:50.

They had widespread, hair-trigger results during avalanche mitigation work.

A lot of slopes avalanched naturally before patrol made it up the mountain.

At 0900 they measured 1.8" of snow water equivalent (SWE) from the last 24 hours at the Alpine gun mount.

We rode teepee sat morning. Pretty good snow but relatively baseless. Broke an arm so fixed and went up blue creek on the west side of IP down Yale Kilgore road. 
we went in about 3pm so it was warm and super dense fog up high towards reas peak. 
rode several draws southwest of the peak prolly about 8000 but could be wrong. 
as we got to the open areas it was already super trenched out and setting up fast forming a nasty ice layer that was everywhere. Open areas, in tight trees etc. 

it was setting up but also warm so kind of turning to corn snow but the ice layer was so thick and rigid it was audible over the sound of the sleds. If you stuck a leg in it wouod grab your leg etc and it was everywhere we rode. 
 

rode until dark then rode out. Seemed to be getting worse the later it got. 
 

heard from others that they experienced similar conditions in big springs. 
 

hope this is helpful :) pin is approximate 

While touring up a low-angle ridge in the northern Lionhead, I experienced several large collapses, notably one that triggered a cornice fall from 50’ away. Another remote collapse caused about 500’ of an E facing bowl to propagate, but not slide. ~9200’ E-SE

Dug a small test pit. Unprofessional observation ectp 10 on the persistent weak layer seen across the advisory area. On our way out near the cabin I cut a line close to a creek to see if I could trigger something. 

About 2 feet of new snow since Friday, 10 inches of that were today. 

Couple collapses... Most aspects. No avalanches observed but visibility has been very low 

We dug snowpits on Saturday. SW facing, 9700 ft. Average HS 120. Several ECTNs 30 down. No propagation. Snow above the 12/21 sun crust is F hard

Also dug a pit today.... NW facing, 9200 ft. HS 125. ECTN12 35 down x2. There is also a thin crust 45 cm down in this pit. 4f snow above. 

Teaching a Level 1 up at Woody Creek Cabin the past couple of days. 2-2.5' has fallen since Friday, but 11" of that snow came throughout today. 

We toured up the East Side of Woody Ridge today. There was heavy snow throughout the day, steady winds (light-moderate) above the tree line all day, and low visibility. No cracking/collapsing, and no observed avalanches in the visible terrain. The skin track was completely refilled on the tour back to the cabin (within ~2 hours). 

We dug below Rip Curl: NE facing aspect @ 8620'.  Average HS 95-105cm. CT8 on the buried surface hoar about 2' down. ECT results: no propagation. The new snow that fell today was F-hard and unconsolidated. 

Likely the same up high, at the house on Horse Butte the storm snow has been increasing in density dramatically since morning.

Moderate SW'ly winds on the ridge were enough to entrain and transport some surface snow. However, windslab formation was very isolated, slabs were soft (4F), and not reactive to ski travel. Most surface snow in the area was unconsolidated, in some cases with a thin (<1cm) surface wind skin.

The top 150 feet of the SE path was scoured with variable ski quality, however below this the snow was largely unaffected by today's wind and skied well. No tracks were visible from previous days.

Around 2pm the base of the clouds descended, and snowfall began at a rate of S-1.

Dug at 7000ft up Brackett Creek near but well below Texas Meadow. HS82 with mid pack weak(er) layers that produced propagation in an extended column test (ECTP13) at around 45cm down. Snowing steadily in the afternoon with no wind at this mid elevation.

Thick and robust ice crust layer widespread above white elephant.  Currently 4-5” of fresh snow on top of crust. Currently snowing heavily with moderate winds SW with gusts. 

This is avalanche weather - heavy snowfall and strong winds transporting snow. With this weather, it doesn't really matter what's going on in the snowpack. The loading from snowfall and strong winds will find the weakest layer in the snowpack and produce persistent slab avalanches.

Snow depths going up from Republic Creek at 8200 ft to the top of Woody Ridge at ~10,000 ft  ranged from 60 cm to 120 cm. Weaker where thinner and stronger where deeper. What surprised me was that we couldn't get a single collapse/whumpf or any cracking despite our best efforts getting off the established skin track. Given the rapid loading and wind loading combined with buried facets, I expected at least on collapse. However, a lack of collapsing doesn't override all the other red flags. 

The snowpack north of town and south of town seemed reasonably similiar. The biggest differences were with elevation. Generally above maybe 9000-9500 ft, the snowpack is a goof 4 feet deep. 

I WON'T BE SURPRISED TO HEAR OF SOME LARGE AVALANCHES AT UPPER ELEVATIONS on peaks like Henderson, Crown Butte, etc where some slopes are being heavily wind-loaded. 

Looking into the future, though, I feel optimistic. The snowpack is growing and will hopefully get stronger in the future as weak layers are insulated and buried more deeply. Yesterday north of Cooke, weak layers generally buried about 2 feet deep showed signs that they were gaining some strength and hardness. We'll see. 

We rode around a big chunk of the Cooke City area from the Miller Road, up to Daisy, around the backside of Fisher Mtn, into Fisher Creek, and looping around Scotch Bonnet Mtn. Ee saw no signs of instability. No cracking or collapsing. While tracks on slopes don't indicate stability, there were a lot of tracks on small test slopes, and none produced small avalanches. 

In all our snowpits, the weak layers were generally 2-2.5 feet deep and I was pleasantly surprised that they seem to be gaining some hardness. It feels that the snowpack has benefited from the steady trickle of light snow in the Cooke area. It hasn't added much water weight, but the continuous light snowfall in the Cooke Area has been slowly insulating and burying the weak layers without stressing them.

Unfortunately, we could not find any buried surface hoar, but we know it's out there. We also know that other areas like slopes south of town up Republic Creek are likely much weaker. 

Without a major load of snow (and water), below treeline, avalanches are still possible but don't feel too imminent. It's different story going above treeline - where avalanches have been happening, where there's lots of wind loading, and where there are lots of potential trigger points. Stay below treeline.

Riding in the vicinity of Fish Creek Trail. Conducted a snowpit, result, ECTX. Snow was stable in this particular spot, did not have enough time to conduct another snowpit. HS 115, melt freeze crust 6-8" below surface, SH at 75cm, facets approximate lower 1/3 snowpack, 2-3 melt freeze crusts in snowpack. Overall 2 cohesive slabs make up the snowpack in this particular snowpit, split by MFcr.  Also in the area signs of wind slabs on N, NE, E, and SE aspects. Airtemp -6C, moderate winds from SW, light snow, and OVC.

On Saturday (12/28) we saw a small avalanche along Lionhead Ridge while riding (photo).

From the highway, with binoculars, we also saw a larger avalanche north of Lionhead Ridge in a large lower elevation steep meadow. This one appeared 1-2' deep and 150-200' wide, possibly slightly wind-loaded, but not a heavily/typical wind-loaded slope.

We also got a vague report of a rider who was partially buried with their sled.