Snow Observations List

From IG 2/18/24: “Human triggered slides in cooke yesterday.”

We were a group of 12 riders skiing the ghost trees up Sheep. We had a safe crossing of the bottom of the large avy slope (south west side of Miller) before skinning up the ghost slope. 
There was 3 other parties, one group of 8, one of 2, and one of 3-4. A few whomps were heard/felt skiing without any propagation or slides on the slope we skied. We did see a few point release slides high up on Miller Ridge later in the afternoon, after the sun had been baking that slope all day. 
The skiing in the Ghost trees was great! Even with all the people. 
we did talk to the group of 3/4. Earlier in the day, they had skinned further up the drainage and climbed up a  west facing rib of Miller proper. On the first steeper slope while skinning up they experienced large snow settling and bailed. 
we could see their tracks, and there actually was a different group that had climbed even higher and skied. We didn’t see any slide activity on the slope they skied. 

On our skin out at 4:30 or so, we could feel the southwest facing snow was definitely sun affected from the solar bake.

From woody ridge, we observed a large avalanche across the republic creek drainage (not sure what the peak is called but see the coordinates). I heard it first since it sounded like thunder or a plane, and then saw a huge cloud of snow moving down the mountain across the drainage.  We do not know if it was natural or triggered by someone.

We also observed large collapsing and whumpfing at the top of woody ridge on wind loaded slopes. Nothing moved as it was less than 30 degrees. 

Probably heard the largest whumph i ever personally heard while skiing near the ridge on the Burn at Sheep Creek. Other groups also reported hearing whumphs too.

while skinning out of sheep on a southern aspect we started seeing signs of warming with little pinwheels but none grew big and none were natural.

From email: "Was in round lake was visiting with a guy in the warm up shack.  He said he caused a decent size avalanche on the sheep mountain side. 

It was roughly 100 feet wide, he was hit by the avalanche but didn’t get buried."

Large slide. Snowmobile triggered. North side Scotch Bonnet Mtn. 

Multiple avalanches north of Cooke City today. On the north side of Chimney Rock a large natural avalanche happened either this morning or late last night, 400' wide and 1-2' deep. I saw several other natural avalanches on the east side of Wolverine Peak and Miller Ridge, the north side of Bull of the Woods Pass and Miller Mountain. These avalanches happened sometime just before or near the beginning of this recent storm. 

Most notably I saw a very large rider-triggered avalanche on Scotch Bonnet that was triggered today, 800' wide, 3-4' deep. Skiers nearby confirmed that they saw riders below or on the slope, however, they did not see the avalanche happen. On the east side of Henderson, I saw another rider-triggered avalanche that happened today, 200' wide, 1-2' deep.  

Saw this avalanche today off miller ridge. Looks to be natural, soft slab 

Sun came out for for a bit around 2pm when I was on top of Henderson Mountain. Got a good look at East facing Miller, South Face of Crown Butte, west side of Sheep Mountain and did not see any recent avalanche activity.  10-12"  new snow in town and on the mountain as of 2pm today. 

Observed a recent avalanche on Henderson Mountain East aspect today. 

From email: "Natural avalanche from yesterday evening or last night.  

North facing aspect, with an interesting 3 tiered crown beginning around 8900'."

We observed three similar avalanches on Mt Abundance today (2/11). All were at about 9,900' and on NE-NW aspects. We were able to safely look at the crown of the first one, which was ~150' wide, 55cm deep, and with an HS of 145. It failed on 1-2 cm buried surface hoar. The other avalanches were on shallow unsupported rocky terrain. All were remote triggered from low angle terrain above, 20-50' away. One of the avalanches sympathetically released a gully and ran 800'.

Natural avalanches observed on east facing aspect of Miller Ridge on 2/11. Larger avalanche propagated widely on the north end of the ridge around 10,000 ft. Smaller avalanche further south on the ridge as well. 

From email on 02/10/2024: "Yesterday, I skied a few Submarine and a few Woody Ridge laps. Collapsing/shooting cracks were widespread and thunderous. Snowfall totals seemed closer to 12” unsettled, with minimal wind. Biggest collapses were near the ridgecrest (1st pic was an impressive shooting crack). 

Today heading up Republic, we observed the crown of a recent avy on Woody Ridge north (pic 2). I wondered for a sec if I had remoted it yesterday but I was further south. The avy looked to originate around 9800’ on a west (slight north) aspect in rocky terrain. Appeared natural from what we could see from the drainage. 

We skied a zone south of woody proper, and had less but still pretty regular collapsing and cracking, though steep tester slopes were nonreactive to ski cuts, surprisingly. Still very little wind. "

We spotted these fairly fresh looking avalanches all side by side with no apparent tracks leading into them. Likely either natural or remote triggered earlier in the day or overnight.

Snowmobiler triggered an avalanche. She climbed up the backside of Crown Butte and as she descended the slope the avalanche broke and ran down the slope behind her. No one was caught or injured 

While splitboarding south of Cooke City today I remote triggered an avalanche. I stopped to transition, stepped into the snow, triggered a massive collapse and a slope about 100ft away slid. I stopped right there to dig a pit. HS 110, south facing, 9,000ft, non wind loaded slope. I got an ECTP 14 and an ECTP 13 both 60cm down, right at the top of the big ol facet layer making up the lower 50cm of the snowpack. 

Other than the remote trigger, lots of small loose dry natural avalanches on all aspects, mid and upper elevations. I also saw a few small D1 natural slab avalanches in the area on east and north facing aspects, mid elevation. Hard to tell when these all happened, but I'd guess within the last 24hrs. Flat light, hard to see definition Large collapses often and throughout the whole area, on and off established skin tacks. 

Natural avalanche on East Side of Henderson Mtn. seen late on 2/7/24. South of the two that Doug saw last week, along the ridge. Could have happened yesterday or last night. I didn’t see it yesterday when riding up and down Fisher creek, but visibility was mediocre. The debris and bed had at least some new snow on it.

Also had a large rumbling collapse near 10,000’ west facing when following one skiers old skin track. And had a few large collapses on south facing slopes between 8,000-9000’. 

From email: "My friend and I toured in Cooke City today. We skied the low angle glades on the South side of Henderson Mountain. Breaking trail, we experienced at least 20 collapses, several of which were large enough to knock snow off the trees around us. Above 9200’ where the snowpack started to deepen, we did not get any collapses or cracking. We dug a quick pit at 9750’ on a SSE aspect. The site we dug on had been wind loaded substantially before the high pressure cycle last week. Skies were mostly cloudy with the sun poking out occasionally, light winds out of the west. Our ECT did not have propagation, but the results from our CT test were poor. Given the sketchy conditions, we stuck to low angle terrain."