Regional Conditions for Cooke City Area

From obs: 5/9/21: "Yesterday we went to check out the new snow in Beehive Basin... Looking down into the face of Peruvian, we observed a natural dry loose slide that released from the ridge... We observed an increase in wind speed throughout the morning, and a shift in wind direction from west to southwest in the early morning moving to west to north west by the late morning. The combination of variable and high winds with the amount of new snow available for transport created a noticeable increase in the hazard of wind slabs on all aspects we observed during the morning..." Photo: E. Schreier

From obs: 5/9/21: "Yesterday... While traversing... along the north ridge of 10602 [in Beehive], we triggered a small wind slab  that carried down into Peruvian, which then released another small wind slab on a northeast aspect of the face (photo). The crown height of this wind slab was measured at 60cm at it's deepest point, and approximately 30ft wide by 10ft long. Looking down into the face of Peruvian, we observed a natural dry loose slide that released from the ridge. We observed an increase in wind speed throughout the morning, and a shift in wind direction from west to southwest in the early morning moving to west to north west by the late morning. The combination of variable and high winds with the amount of new snow available for transport created a noticeable increase in the hazard of wind slabs on all aspects we observed during the morning..." Photo: E. Schreier

Small wet loose slide that a skier triggered, running over an older crown from prior days. East aspect, 10,000'. From 5/7/21. Photo: D. Britt

Photo of a large natural wet avalanche in Taylor Fork, NNW aspect around 9,000' elevation near Koch Peak, on 5/3/21. Photo: D. Britt

From email 5/2/21: "Small but plentiful wet snow avalanches in Cooke City today. Didn’t see any that were broke on a deeper scale." Photo: K. Goodyear

From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". Photo: J. Harrison

From obs: "I traversed the Bridger range yesterday (4/28/21). The alpine start was good and solid but I saw lots of recent avalanches that looked super wet, some that had broken a couple feet deep. Conditions were pretty stable until about 1300 when that most recent snow layer started to really want to slide on the crust. Once I was in the meadows between Baldy and the M, at about 1400, I started hearing/feeling really wet "whumps". Photo: J. Harrison

From obs 4/28/21: "Observed numerous natural wet loose slides probably occurring over the past 48 hours on NW-W-S aspects mid-elevation. Point releases from rock bands and couloirs shedding. Photo for example, which shows W facing bowl with slides visible from US-89 in Paradise Valley. These are between 8500’ and 9500’ on an unnamed peak just northeast of Dexter Point." Photo: T. Benson

From obs 4/9/21: "...we saw widespread natural wind slabs on N-NE eastern slopes in the Northern Absarokas (photo). Winds increased throughout the morning, and evidence of wind transport became more apparent at higher elevations. We found that on aspects unaffected by wind loading, the new snow layer was not cohesive and only saw minor sluffing." Photo: E. Schreier

Skiers had a collapse which made this crack on a south facing slope with a shallower, wet snowpack around 9,000' near Cooke City. Photo: J. Redfield

This wet slab was reported on 4/4/21 around 8,200' elevation in the Main Boulder drainage south of Big Timber, outside of our advisory area. It happened that day or very recently during extended above freezing temperatures. Photo: G. Smith

3/28 Wolverine Peak wind transport. Also had 6 inch wind slab break and run in Y couloir on Miller the day before. Photo: G Smith

Extreme winds on 3/28/21 transported snow that fell over the past week into fresh wind slabs. Photo: BSSP

Fro obs: "... an avalanche we saw out by Goose Lake yesterday (3/27)... we are pretty sure this wasn't there at 8am. On the way back (5pm) we noticed this large avalanche on the NE face of Iceberg Peak at about 11,200. It broke naturally in the new snow which was drifted heavily by SW winds (20-40mph all day). It appears to be 3-4' deep at the deepest spots, 600' wide, and ran 750'. There is a small area below the upper crown that stepped down, but tough to tell if that was just snow from the start of this storm. We did not notice any other activity in the area..." Photo: M. Cohen

"Couple good size point releases on the East side of Henderson Mtn." Observed 3/27/21. Photo: D. Green

Ian and Dave stop to do a quick stability test as they hunt for a layer of weak snow 1-2 feet under the surface. Photo: GNFAC

From obs: "On our way up the summer trail route to Hyalite Peak our party of three remotely triggered a small avalanche from the skin track at around 9,600ft on a east facing aspect. The storm slab went about 4 inches deep and 150-200ft across a small roll over feature. We were about 150ft away when we triggered the slide." Photo: C. Kussmaul

From email on 3/12/21: "...silver creek up to the saddle of Meridian in the NP yesterday. ... It was on the S aspect at 9,500ft of the shoulder that takes you up to the steep trees W of Meridian. It must have occurred in the last 24-48hrs due to not much snow had fallen since the avalanche occurred. It ran out down into the trees below. ... The crown looks to be over a foot deep, and the length must have been 50ft"

Photo: P. Whitmire

Skier triggered loose snow avalanches occurred on 3/10/21. S aspect at 10,000' elev. Photo: GNFAC

Small slabs and sluffs near Cooke City, seen 3/11/21 and broke in the 8-10" of snow that fell on 3/8-3/9. Photo: GNFAC

Skiers in Cooke City noted this natural storm slab that released on an east aspect at 9000' on March 9th. It broke 6" deep and 25' wide. Photo: B. Fredlund

A rider triggered this avalanche on Top of the World ride east of Cooke City on March 5th after cutting across the slope twice. Photo: K Sorensen

Cornice collapse (3/8) on a small slope West of Cooke City in Yellowstone National Park. Photo: J Logan

From obs 3/6/21: "Observed several smallish avalanches in Yellowstone National Park today. The interesting thing about this one is the bison track that goes into the slide. No telling if the avalanche was triggered by the bison, but the shallow snowpack is about 1/2 faceted, so maybe it was remotely triggered." Photo: J. Logan

From obs on 3/6/21: "Small slab avalanche with snowmobile highmark tracks. They do not appear to be related, since there are no tracks into or out of the slide. Approximate coordinates 45 4.313 x 109 55.380" Photo: R. Taylor

Observed 3/4/21 just west of Cooke City. SE aspect, 9300' elev. Looks to have ran in the last 48 hours. Photo: B. Fredlund

From email: "I saw some older slab avalanches on The Thunderer mountain, in northeast YNP (observed today). These avalanches happened on westerly aspects around 9700'. I'd hypothesize that they happened in correlation with the very strong westerly winds that happened around Feb. 21-22." Photo: B Fredlund

From email: "I saw some older slab avalanches on The Thunderer mountain, in northeast YNP (observed today). These avalanches happened on westerly aspects around 9700'. I'd hypothesize that they happened in correlation with the very strong westerly winds that happened around Feb. 21-22." Photo: B Fredlund

This avalanche likely release naturally Sunday night (2/28). Photo: C. Tuholske

This avalanche was triggered by a snowmobiler on Saturday (2/27). Photo: C. Tuholske

Skiers saw this slide in Hayden Creek on 2/25/21. It appeared up to 4-6' deep and 200' wide. ENE aspect at 9,800' elev. Photo from IG: @vt.to.mt

Skiers saw this slide in Hayden Creek on 2/25/21. Photo from IG: @vt.to.mt

Skiers saw this slide in Hayden Creek on 2/25/21. Photo from IG: @vt.to.mt

Avalanches seen on windloaded slopes in Hayden Creek. Likely broke 2/21 or 2/22.

Photo: M. Simone

This natural avalanche on the SE shoulder of Mt Abundance avalanches regularly from wind-loading. Photo: S. Strenge

This avalanche on the east face of Wolverine Peak outside Cooke City was triggered by a cornice on 24 February. Although it did not propagate wide, it ran far. Photo: S. Strenge

A natural wind slab avalanche beneath a cornice on Henderson Mountain, near Cooke City. It appears to have broken at the new-old interface, 2-3 ft deep and ~300 ft wide. Likely ran overnight on Monday 2/22/21 or early morning Tuesday 2/23/21. 

Photo: GNFAC

A skier saw this natural avalanche at 9,000' on the east side of Republic Mountain on Tuesday, 2/23. Photo: J. Dobronyi

Snowmobile triggered slide on Crown Butte, outside Cooke City. 2/18/2021

Snowmobile triggered slide on Crown Butte, outside Cooke City. 2/18/2021