Snow Observations List

We rode into Tepee Basin. There was 1-2 feet of new snow with a few inches falling during the day. In a brief period of clearer skies we saw two natural avalanches on the steep slopes above the basin. Neither was huge, R2-D2. One ran about 500', both looked to be 1-3' deep. We saw another natural avalanche near Bacon Rind into the Gallatin River. 

The avalanche warning was certainly justified. We did not go near any steep terrain. Dug one pit and measured 1.8" SWE in the storm snow. ECTP 20 about 2 feet deep and an ECTP23 failed on the basal facets. We would plan to avoid steep slopes and runout zones for a while waiting for things to stabilize. 

Rode out Buck Ridge through 2nd & 3rd Yellowmules, McAtee Basin, and then out to Cedar Mtn. Saw no avalanches or signs of instability (no cracking, no collapsing). There were a few inches of new snow (2-4") that had been blown around by very strong winds. Fresh wind drifts had formed overnight on the trail and in spots our tracks were blown in by the time we were headed back out. The chief avalanche concern today was avalanches breaking in wind drifts. The possibility of triggering a slab breaking deep in the snowpack was a secondary concern. 

With snow and wind on the way tonight and through tomorrow, avalanches in the new snow and deep in the snowpack will both be more likely tomorrow. Expect an elevated danger. The details will depend on the amount of snow and wind, so make sure to check the forecast in the morning. 

I went on a little loop up and around Red Mountain today, and have a couple slides to report. Most notable was one that spanned about 2000’ of the north side of Red Mountain. It seemed to be 1-3’ deep in the newer snow, for the most part, but a portion of it broke 15’+ deep and ran at the ground. Judging by how little snow was on the debris, I’d guess it ran sometime Friday night or Saturday. This bowl frequently produces large avalanches, but this one was a real peach. 
I also saw another (much) smaller 1-2’ deep slide on the west-facing road cut just north of the Bacon Rind pullout. 

Via IG: “Large natural avalanche on the east side of redstreak peak down near West Yellowstone. 

And then another natural one right on the shoulder of white peak on the boundary.”

Via IG: “Electric peak via Betty gulch avalanches. Assuming they are natural!”

Big (tennis court size) collapse and whumpf on the upper meadows at Telemark Meadows in flat terrain. No other reactivity to report from a few laps on the main ski slope. 

Today we rode north of Cooke City and looked at recent natural and Human-triggered avalanches. The slide on Fisher Mtn. was very large and appeared up to 10 feet deep. It had much more volume in the debris than the slide that was triggered on this same path in December.

We also looked at the slide on Crown Butte that was triggered by a snowmobiler yesterday. This was on a SW aspect at 9,600'. It was 1-3 feet deep and broke on a layer of surface hoar and large facets below a hard slab of wind-drifted snow. 

We saw two slides that had not been reported previously. One natural on the east side of Sheep Mtn. that was a hard slab of wind-drifted snow on a heavily wind loaded slope near the high ridgeline at 10,500'. The second was snowmobile triggered on a path called "Marty's" above Daisy Pass road. This was similar aspect as the slide on Crown Butte yesterday, and likely had a similar snowpack structure. We checked the debris for a beacon signal to be sure no one was caught, and did not find one. This may have been triggered today (3/12).

This recent activity is a clear sign the snowpack remained unstable with the recent loading event. Due to these slides breaking on persistent weak layers, I think similar human-triggered avalanches remain likely.

Heard tree breakage, saw plumes of snow and sliding snow at the bottom of the slide path. Our group spoke with the sledders and skiers that were on slope and confirmed  none were caught. Skiers reported feeling slide tremble and backed down the mountain. Main breakage was near top of the third shoot from the lookers right. 

I triggered a avalanche on the way back down the mountain. I'm unsure of the exact location but a buddy said it was under bear tooth butte. I was able to outrun the avalanche and there was no injuries.

Noticed this large avalanche in unsupported terrain yesterday morning. I called it HS-N-R3-D3-U although it looks to have failed on facets at the ground. Frequent flyer but impressive. Debris was approx. the size of a football field and 8-10' deep, ran full extent of D3 track.

We dug on a nearby slope. 8050', E/SE, 29 deg. HS 200cm, N/O interface down 40cm. 1cm MFcr with small grained facets above and below. Fair structure, no prop. A bit of grapple mixed in new snow and todays solar input was not warm enough to soften current surf. crust

(screenshots from IG story)

From FB message: "triggered this today (3/11/23) in Cooke City south side of Crown Butte."

From obs 3/11/23: "Saw a deep crown today in Republic Valley. This is peak 10383 (just north east of republic peak). Crown looks about 100 feet wide and probably 5 feet deep. Couldn’t see debris or how far it ran."

Skiing the slopes in Pebble Creek was pretty awful - very wind affected.  But the exit to the highway was great.

While driving into Cooke City this afternoon I saw recent large (D2) natural avalanches on north and northwest aspects above Silver Gate, and there was a large avalanche in the main gully on Town Hill (southerly aspect) above Cooke (photos attached).

From IG message: "3 different slides lionhead area. One was very big the run out was 20 feet tall and quarter mile long"

Several avalanches observed D2-D2.5.
Crown depth 80-120cm
ENE @ 10,000’

E @ 9700’

SSW @ 8800’

On Saturday we toured up Dudley Creek. At around 1pm we ski cut an isolated, wind loaded pocket on a SE aspect at approximately 9200ft elevation and released a wind slab (see photo). The slab was about 20 feet wide, about 1 foot at it's deepest, and ran for about 200 feet. Staying wary of wind loading, we dug a pit on a NE aspect, in a spot without evidence of significant wind loading, and received an ECTNX. Although we did not identify any failure on buried weak layers in this location, it will remain something to watch for with more snow and warmer temps on the way. 

PHotos attached of some natural avalanches near Cooke City today.

Avy1: NW aspect, around 10,000'. (This starting zone also avalanched in a similar way around Feb. 21).

Avy2: E aspect, around 9,000'.

Large avalanche with small tree and branch debris. Located on the lower NE bench face of Mt Abundance, near Lake Abundance. There were snowmobile tracks near the slide but could not determine if that was the cause. Approx 2000 feet across. Possibly 4-6 feet deep but couldn't tell from the bottom of the hill.