Snow Observations List

From email 5/11/24: “Hey Guys, here are a few photos from the weekend. The sheep Mountain Avalanche was Snowmobile triggered on Friday and the fisher peak avalanche happened today. Maybe cornice drop?”

From IG message 5/10: "Made it most the way up Ross today turning around at the step up to the east shoulder. New snow is resting on a layer of graupel. New snow has not bonded to the old. CT12, Q2 at 90cm from the ground. HS=150cm'

Up on the Ridge this morning, the recent snow had developed a 3-5 cm crust, and remained moist underneath. No active signs of instability while the snow remained cold, except for the various crowns from slides which broke during the storm (Avalanche Gulch, North Bowl, etc.), and lots of rollerballs from yesterday. Within an hour of sunrise the surface crust began to break down, and small loose releases were beginning to rain down from cliffs and around the large cornices. The cornices, some reaching the size of a small car, were already visibly sagging and many smaller cornices easily released under body weight.

From IG story 5/8/24: "@mtavalanche remote triggers today in Cooke City. 2-4' of fresh north of round lake."

From email 5/8/24: "A few snaps from today. Observed several D2 slides between sluice box and the nose. I didn't see the toe of these slides, but it looked like there were running with some speed into mid elevation terrain. Slabs were most common in winded terrain, but slides flanked out on new/old interface and 4/26 crust (these layers are not very far apart) even in sheltered middle elevation terrain. Visibility was poor, but I'd expect to see similar large slides in steep, winded terrain

4/26 crust down:

55-60cm at 6500

65-70cm at bridger mid 

75+cm at ridgeline"

A skier near the top of the Alpine Lift at Bridger Bowl ski area took a photo of three avalanche crowns near Peter’s Point. 

A skier triggered an avalanche on a test slope in Beehive Basin, breaking 12-16" deep and 75' across. The slide failed within the new snow. 

Saw a very large crown on a north face of a peak west of the hyalite area. Potentially peak 9662. The crown appears to wrap around multiple aspects for about 1/4 mile. Seen from the Bridgers around noon on May 4th. Probably went during this weeks storm, but it looks to me like it was much deeper than a storm slab.

On 5/4/24 “…. a friend toured around Wolverine today. On his way out he heard a slide breaking trees (just before noon). Unknown location but he said it sounded like it was around/ above Texas Meadows. The action continues!”

Our party (3) triggered a significant wet loose slide on the fin today. I, the first skier dropped in next to existing tracks from earlier in the morning. I made a couple of small turns in unskied snow to test it and decided that not much was moving. As I continued down the wet surface snow started to slide and accumulate. My partner called me on the radio to tell me a lot of snow was moving behind me and I cut left. I traversed hard to lower angle terrain until I felt I could safely descend the rest of the slope.  My partners descended the bed surface until they could traverse out. 

We made several key mistakes today.  We knew it would be warm and that we should be up and down early.  We left later than planned, moved slower than expected and failed to adjust our plan.  We mistook lack of wet loose activity on similar aspects and elevations on features we could see as sign of stability.  We failed to make a plan B or establish a turnaround time.  We interpreted a party ahead of us that skied the slope as a go ahead.  Another party approaching behind us added pressure to go. They also skied the slope after us in similar style to my partners.

In our favor, we communicated well, radios were key, stayed calm and we managed ourselves through the situation. I feel humbled and lucky to have gotten away with a free lesson.  One that I didn't think I should have needed.

Wind load on old crust, probably from Wednesday. 

From email 5/2/24: "Triggered in the virtues this evening. 40' wide, 4-12" deep, failed as a dense, wind-packed slab on the rain/sun/heat crust underneath the most recent snow.  I had marginal visibility but it looked like there were similar small-ish wind pockets that had failed in a few spots. Good skiing up high, fun first day up there."

From email 5/1/24: "Hi crew. I triggered a soft slab avalanche on the North side of Sheep Mountain today. D1.5 200’ wide ran 200’.  Crown was 6-12’’ deep. I was able to ride out of it and anchor in a safe spot. 

It broke on our 7th lap and we had seen no signs of instability prior to the avalanche but wind loading was occurring and obvious. The avalanche broke and on a dirty crust that formed during a rain event last week."

Toured up to Bradley's Meadow, and found about 6 inches of moderate density snow sitting on a thin M/F crust with wet snow underneath the pack. 

Snow seemed well bonded and did not see any natural slides up on ridge. Not much sun was out, and it was snowing until 12 p.m. 

Skied north of Cooke City the last couple days ( Sat. 4/27 and Sun. 4/28), near Lulu Pass and Henderson Mtn.. Yesterday there was 2-3" of moist new snow, and the snowpack below had not refrozen up to 9500-10k', it was very wet and unsupportable below the new snow. Moderate east wind yesterday drifted the new snow into small slabs up high.

Today there was 1-2" new snow on top of a thin, breakable crust around 9,000', with wet unsupportable snow below the crust. The crust softened quickly in any sunshine midday. Pulses of heavy snow mixed with periods of partial sunshine and calm-light wind.

Saw only small slabs crack beneath skis along the ridge yesterday, and minimal wet snow avalanche activity. Despite minimal observed avalanche activity, it seemed like a skier or rider could trigger a larger wet avalanche, especially on slopes that received sunshine.

Photos attached of what appear like wet slabs possibly from Friday when the precip. started after the first night or two of poor freeze (North side of Republic, and Henderson Bench).

We toured to Elephanthead Mountain today (4/27/24). Most of the couloirs emptying into Mission Creek (e.g. Das Ist Ice, Pitchfork Couloirs) showed signs of recent, large scale wet slides. Higher on the mountain, we observed fairly recent avalanche debris and crowns of 4-5 feet. On our descent of Mission Creek, we crossed large, wet slide debris fields that buried our earlier skin track (see pic). Our decision was to stick to low angle terrain and to steer clear of runout zones of any couloirs.  

We toured into beehive today starting at around 7:30 AM. We found about 2-4" of fresh wet and heavy snow. Lightly snowing all day until we left around 12 when the snow picked up a bit. Passing fog in and out all day. Around 9400' we dug a pit to the ground (east facing). ~95cm deep. We found about 5" of thick snow from the last two days, on top of a thin layer of graupel and ~4" of very wet snow that had not refrozen from the previous warm-up. The rest of the snowpack was also wet to the ground, but not to the same extent that the upper couple of inches were. Near the ground was definitely a weaker structure, but was also now saturated and closer to "corn snow" than anything. Also noted an ice layer about half way though the snow pack. 

In our pit we got cracking in the new snow (ECTN9) and in the top (8-9" down) of the saturated snow pack (ECTN18), but no propagation. A shovel shear test revealed our two layers being about 8-9" down at the bottom of the very wet layer, and at the interface with the ice layer halfway down. No collapses were observed. No avalanches were observed. We got some sluff while we were skiing, but only when skiing/hop turning aggressively. We chose to ski some steep and short couloirs.

The skin track had decent coverage besides a few spots in the trees. It was rain mixed with snow in the parking lot around 12:45, which quickly turned to rain as we drove towards big sky.

On 4/26/24 large natural wet slabs were seen running on Wall Mountain near Silver Gate. An observer from Beartooth Powder Guides sent us a video of them happening at 3pm while it was 43 degrees F. I also noted a similar large crown on the north side of Republic Mtn. that probably also happened this afternoon.

From IG on 04/26/2024