Regional Conditions for Southern Madison

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 (4/18/21): "...class split and dug three pits, one on NE, one on N, and one on NW at 7623'. HS averaged around 70 - 100 cms... The NE and NW facing pits showed rounding depth hoar and no sudden CT results. None of the ECTs fractured or propagated. The N facing slope still had preserved advanced depth hoar 3 mm in size (see image)..." Photo: J. Quinn

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

Two natural avalanches in Sunlight Basin occurred on a heavily wind-loaded slope. Also, note the very large cornice overhanging the slope. Avoid getting on top of or underneath these large overhangs of snow as they can break unpredictably. Photo: GNFAC

A small, natural avalanche in Sage Basin occurred on a heavily wind-loaded slope. Also, note the very large cornice overhanging the slope. Avoid getting on top of or underneath these large overhangs of snow as they can break unpredictably. Photo: GNFAC

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

From obs 3/28/21: "Saw this slope which frequently slides had been triggered on our way out last night [lower left in photo]. Slid to the ground but I expect it was mostly new snow as there is a larger old crown visible further uphill... I did see two other small pocket slides yesterday also in new snow on bed surfaces of older slides... General snowpack is getting very deep now but a thick junk layer remains at the ground everywhere I dug sleds out." Photo: J. Gerardi

From obs: "Deep slab avalanche in Blackmore Basin that appeared to break on the depth hoar near the bottom of the snowpack. It was on a wind loaded NE facing slope at approx. 9,500 and looked to break on a slope in the 35-40 degree range. The crown was about 8'-10' deep and 200' wide. It broke to the ground and ripped out several small trees." Photo: JR Mooney

From obs (3/27/21): "We were skinning up Pyramid Point from the East. as we approached 10,000 ft, we encountered a wind slab on an East Facing slope. it was about 1-2 inches where we encountered it, but it quickly propogated. the crown was 18-20 inches at its highest and about 150 feet wide. the debris ran for about 200 feet."

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

On shady aspects, there is a layer of weak near-surface facets developing. These could become a problem if they get buried by new snow this weekend. On sunny aspects, the snow surface is getting wet and is becoming weak as it heats up in the afternoon.

In this photo, observe how both issues can occur on the same slope. 

Photo: GNFAC

Small wet slide on south facing slope low on Skyline Ridge. Observed 3/13/21. Likely broke in the previous couple of days.

Photo: GNFAC

Deep slab avalanche on Arden Peak at the back of Maid of the Mist basin in Hyalite. Probably broke between Feb 22 and Feb 28, 2021 Photo: GNFAC

Seen from near Ennis on 3/4/21. On Finger Mountain in the southern Madison Range. Photo: D. Frohman

Seen from near Ennis on 3/4/21. On Finger Mountain in the southern Madison Range. Photo: D. Frohman

We saw these recent wet loose avalanches on 3/6/21. SW aspect, 9,100'. They likely ran during above freezing temperatures between 3/3 and 3/5. Photo: GNFAC

From obs: "Small D1 avalanche on south-eastern aspect around 7800ft. Looks like solar released on older layer a day or two ago."

Photo: M. Mailly

From obs: "While touring above the canyon this morning, I noticed a very recent wet slide (would guess this incident occurred yesterday afternoon, March 4th). This was a skier triggered slide on a E aspect at an elevation of 7200. This slide was roughly 50 feet wide and ran about 50 feet, I estimated this crown to be 2-3 feet deep, slid all the way to the ground. This occurred below a steep roller."

Photo: T. Saulnier

"On the drive back we saw a large crown on the NW face of Big Horn peak..." (likely broke Sat or Sun, 2/27-28). Photo:  S. Jonas

Wet loose avalanches released in the warm sunshine on Tuesday, March 2nd. We expect many more in the coming days. Photo: S. Jonas

Sled Skiing in Third Yellow mule... after an air onto the slope the impact from landing resulted in a fracture and failure to / near the ground... in addition, a remote trigger occurred on adjacent slope... 200-300 ft to the skiers right. No body was caught in either slide. Skier that initiated failure was moving at high speed and was beyond slide path before majority of snow movement began. Photo: W. Miller

Sled Skiing in Third Yellow mule... after an air onto the slope the impact from landing resulted in a fracture and failure to / near the ground... in addition, a remote trigger occurred on adjacent slope... 200-300 ft to the skiers right. No body was caught in either slide. Skier that initiated failure was moving at high speed and was beyond slide path before majority of snow movement began. Photo: W. Miller

Sled Skiing in Third Yellow mule... after an air onto the slope the impact from landing resulted in a fracture and failure to / near the ground... in addition, a remote trigger occurred on adjacent slope... 200-300 ft to the skiers right. No body was caught in either slide. Photo: W. Miller

This avalanche was triggered on Sunday, 2/28, when a skier released another slide 2-300 feet away. It broke at the same time. No one was caught. This was in the Third Yellow Mule on Buck Ridge.  Photo: W. Miller

From obs: "With recent persistent winds the cornices are growing to impressive size. Noted a few natural cornice drops on the south 'rim' of Sage Basin." Photo: R. Larson

Riders triggered this slide on 2/28/21 near Red Canyon/Cabin Creek, north of West Yellowstone. Nobody caught or injured, but close call.

Riders triggered this slide on 2/28/21 near Red Canyon/Cabin Creek, north of West Yellowstone. Nobody caught or injured, but close call.

Riders triggered this slide on 2/28/21 near Red Canyon/Cabin Creek, north of West Yellowstone. Nobody caught or injured, but close call.

Riders triggered this slide on 2/28/21 near Red Canyon/Cabin Creek, north of West Yellowstone. Nobody caught or injured, but close call.

This recent avalanche failed on a heavily wind-loaded slope in Sage Basin along the ridgeline. It may have initiated as a cornice fall or a wind-slab, but it broke down to deeply buried facets. Even though it was a small slope, the slide had enough power to knock down a tree and piled debris deeply at the bottom of the slope. Photo: GNFAC