Regional Conditions for Bridgers

Debris pile from the smaller of two wet slab avalanches on the south-facing chutes off of Texas Meadows. P: A. Schauer

Photo of the track of the larger of two wet slabs on the south-facing chutes off of Texas Meadows. Photo: A. Schauer

Two wet slabs that looked to have released during the past 48 hours. The smaller slide on the left had a debris pile that was 6' deep. The larger slide on the right failed at the ground and took most of the snow in the chute with it. The large slide may have been triggered from smaller loose wet slide that was set off by a skier. Photo: A. Schauer

Large debris pile from a recent wet loose avalanche north of Bridger Bowl. Photo: A. Schauer

Outside Cooke City up Zimmer Creek, a skier spotted this cornice fall which triggered a small pocket down low. Photo: F. Madsen

Many wet loose and wet slab avalanches were seen near Zimmer Creek (north of Cooke City) on south and east aspects. Temperatures were warm at 10,000 feet. Photo: F. Madsen

This photo near Lionhead, is indicative of the wet loose avalanches we are seeing on many low elevation, south facing slopes throughout our advisory area. Daytime temperatures near 50F will make avalanches like this more frequent and widespread in the coming days.

Low angle metal roofs have heavy, thick slabs of snow that built up during persistent cold temperatures. These slabs will slide during warm temperatures. Be on the lookout for overhead hazard and be cautious where you walk or park your car during warm sunny days. An additional urban hazard are large icicles are that will break during warm days. Photo: A. Schauer

On Saturday (3/16) in the northern Bridger Range we saw natural and skier triggered wet loose slides that were small, but could have severe consequences if they catch you in unforgiving terrain. Photo: GNFAC

We saw old wind slab crowns near Fairy Lake on Saturday (3/16). These types of slides are now unlikely to trigger, but worth keeping in mind in steep heavily wind loaded terrain. Photo: GNFAC

We saw old wind slab crowns near Fairy Lake on Saturday (3/16). These types of slides are now unlikely to trigger, but worth keeping in mind in steep heavily wind loaded terrain. Photo: GNFAC

On Friday (3/15) dry loose avalanches were easily triggered on steep terrain in Hyalite. Six inches of recent snow easily slid on crusts buried below it, and was drifted into small wind slabs near ridgelines. These types of small slides are typically not large enough to bury a person, but are dangerous if they catch and carry you over cliffs or into trees. Photo: GNFAC

Skiers in the Northern Bridgers noted signs of instability in wind-transported snow and were able to trigger a wind slab. From the email: "My partner and I toured up in the Northern Bridgers today near Ainger Lake and found conditions to be more touchy than we expected. The wind was blowing hard when we entered the basin, and we observed some snow transport. As we got higher, we observed variable wind affected snow and thin wind slab, and dug a pit finding no notable weak layers aside from the wind slab which was breaking off in chunks as we skinned. We witnessed a shooting crack through the wind slab that was 2-5 cm thick where we were, and soon after triggered a small slide and turned around. At its deepest the crown was around 15 cm thick, so a lot thicker than what we had previously been seeing! It wasn't a problem where we were, probably about enough to knock someone down and take them for a short ride, but could have been consequential in more dangerous terrain." Photo: E. Birkeland

Skiers in the Northern Bridgers noted signs of instability in wind-transported snow and were able to trigger a wind slab. From the email: "My partner and I toured up in the Northern Bridgers today near Ainger Lake and found conditions to be more touchy than we expected. The wind was blowing hard when we entered the basin, and we observed some snow transport. As we got higher, we observed variable wind affected snow and thin wind slab, and dug a pit finding no notable weak layers aside from the wind slab which was breaking off in chunks as we skinned. We witnessed a shooting crack through the wind slab that was 2-5 cm thick where we were, and soon after triggered a small slide and turned around. At its deepest the crown was around 15 cm thick, so a lot thicker than what we had previously been seeing! It wasn't a problem where we were, probably about enough to knock someone down and take them for a short ride, but could have been consequential in more dangerous terrain." Photo: E. Birkeland

Snowboard-triggered wind slab near Fairy Lake in the Northern Bridgers. Photo: E. Marcoux

We found a deep snowpack and good stability near The Throne in the northern Bridger Range on Saturday (3/9). Photo: GNFAC

This slide was triggered on a steep (40 deg) southeast facing slope at Round Lake outside Cooke City. It failed 8" deep on a layer of graupel and small facets. An adjacent hill slid at the same depth beforehand. This layer is not on most slopes, but as this slide shows it is on some. Doug was in the area and dug a pit in the crown soon after it was triggered. Photo: J. Fritz

This slide on the NE face of Blackmore was triggered by the second skier. It was 8-12" deep and 100' wide and likely failed on small faceted crystals underneath the new snow. No one was caught. Going one at a time was good travel behavior that can save our lives when things go wrong.

Loose snow slides are possible on sunny slopes during intense spring sunshine. Recent snow is unconsolidated and it may be easy to trigger loose slides on some steep slopes. Photo: G. Antonioli

From BBSP on 3/2/19: "Large natural avalanche pulled out last night/early morning on the backside of north peak of saddle peak in Bostwick canyon, the slide path is known as the 'Y' to local skiers and hasn't run this year, or been skied. Crowns looked to be 3-6ft, it ran further than anything i've seen there in the past decade, knocking over small trees and some old standing dead in the run out. R3 D3.5." Photo: BBSP

From BBSP on 3/2/19: "Large natural avalanche pulled out last night/early morning on the backside of north peak of saddle peak in Bostwick canyon, the slide path is known as the 'Y' to local skiers and hasn't run this year, or been skied. Crowns looked to be 3-6ft, it ran further than anything i've seen there in the past decade, knocking over small trees and some old standing dead in the run out. R3 D3.5." Photo: BBSP

A skier reported seeing multiple recent avalanches near the Throne. They dug a pit and got propagating results failing at a density change within the new snow. From the email: "Around a foot of wetter, denser new snow (F+) slid on a dryer new snow interface (F-)". Photo: C. Kussmaul

The avalanche can be seen in the center of the photo. Snow on the lookers right flank also avalanched from wind-loading. There is still a lot of snow that did not avalanche, which is still dangerous and could slide. Photo: GNFAC

The crown looks to be 4 feet deep and 100 feet wide. It is bigger than it appears in the picture. There is still a lot of snow above the crown which could avalanche. Photo: GNFAC

The lower of the two crowns may have been triggered by the two rescuers as they entered the slope. Photo: GNFAC

The crown of the avalanche is marked in red. The skier was a few turns into his run when it broke above him. Photo: GNFAC

The crowns in the upper path are marked. The X is the approximate location of the victim. Photo: GNFAC

Skiers reported intentionally triggering multiple avalanches failing up to a foot deep at the Throne. From the email: "We dug a pit above the top of the throne (ENE aspect, 8400’, 28°) and got an ECTP17. The pit broke below 55cm of new snow, on top of an old wind slab. Bailed on our objective (the ruler) and skied the main ESE chutes on the throne. Ski cut the top of all 3 chutes and got them all to break out 8-12” deep, 100-200’ wide and they all ran 500-700’ into the trees at the bottom of the gullies. The runout hit the trees at the bottom with enough force to snap 3” trees and piled up debris up to 5’ deep." Photo: M. Cohen

Skiers reported intentionally triggering multiple avalanches failing up to a foot deep at the Throne. From the email: "We dug a pit above the top of the throne (ENE aspect, 8400’, 28°) and got an ECTP17. The pit broke below 55cm of new snow, on top of an old wind slab. Bailed on our objective (the ruler) and skied the main ESE chutes on the throne. Ski cut the top of all 3 chutes and got them all to break out 8-12” deep, 100-200’ wide and they all ran 500-700’ into the trees at the bottom of the gullies. The runout hit the trees at the bottom with enough force to snap 3” trees and piled up debris up to 5’ deep." Photo: M. Cohen

Natural avalanche on the west side of the Bridger Range. Occurred on or before 1/27. Photo: GNFAC

Bridger Bowl Ski patrol snapped a photo of this natural slab avalanche on the west side of the Bridgers near Truman Gulch. Photo: BBSP

Skiers in the Bridgers saw multiple large natural avalanches in the Bridgers that had released during recent snow and wind loading. From the email: "Looks like things really went off in the Bridgers in the last few days. Loads of natural avalanche activity, much of it appearing to fail on deeper layers than the new/old interface." This is the third large avalanche that has been reported on Bridger Peak this season. Photo: B. VandenBos

Skiers in the Bridgers saw multiple large natural avalanches in the Bridgers that had released during recent snow and wind loading. From the email: "Looks like things really went off in the Bridgers in the last few days. Loads of natural avalanche activity, much of it appearing to fail on deeper layers than the new/old interface." This avalanche in the Hourglass was triggered by a large chunk of cornice that broke off. Photo: B. VandenBos

Skiers in the Bridgers saw multiple large natural avalanches in the Bridgers that had released during recent snow and wind loading. From the email: "Looks like things really went off in the Bridgers in the last few days. Loads of natural avalanche activity, much of it appearing to fail on deeper layers than the new/old interface." Photo: B. VandenBos

A group with the MSU advanced avalanches class found multiple slab avalanches that released at various times during this week's storm. Three of the slides ran for a large portion of their slide path. This debris pile was from an avalanche that likely failed Friday morning, and was large enough to break small trees in the slide path. Ski tracks nearby suggest this avalanche was skier-triggered. Photo: A. Schauer

A skier unintentionally triggered a slab avalanche in the northern Bridgers. The group did not notice any avalanche activity on the snowmobile ride in to the zone. They dug a pit and found poor snow structure and propagation in the new snow layer in stability tests. From the email: "About halfway up my hike I heard a wumpf and started getting carried down. I was carried about 90 yards, I got fully buried for the middle 30 yards but finally surfaced and came to a stop. My two friends were on their sleds over to the side of the face and had eyes on my the whole time. We all had the proper equipment but luckily didn’t need to use it. The crown broke about 40 yards above me, looked about 3.5 ft deep, it went across the 40 yard wide couloir and continued down and around some cliffs another 20 yards." Photo: C. Histon

A skier unintentionally triggered a slab avalanche in the northern Bridgers. The group did not notice any avalanche activity on the snowmobile ride in to the zone. They dug a pit and found poor snow structure and propagation in the new snow layer in stability tests. From the email: "About halfway up my hike I heard a wumpf and started getting carried down. I was carried about 90 yards, I got fully buried for the middle 30 yards but finally surfaced and came to a stop. My two friends were on their sleds over to the side of the face and had eyes on my the whole time. We all had the proper equipment but luckily didn’t need to use it. The crown broke about 40 yards above me, looked about 3.5 ft deep, it went across the 40 yard wide couloir and continued down and around some cliffs another 20 yards." Photo: C. Histon