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.
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.
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.
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.
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.
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.
