Regional Conditions for Northern Gallatin

A skier sent in photos of multiple loose wet avalanches near Mt. Blackmore yesterday. Photo: G. Antonioli

Recent dry slab avalanche that was triggered by a falling cornice and failed at the ground. Photo: G. Antonioli

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 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

This dry loose avalanche was intentionally triggered by a skier in Hyalite. Although generally small, dry loose avalanches can generate enough force to push skiers or riders into rocks or trees. Photo: C. Kussmaul 

A snowmobiler saw this recent activity on Saturday 3/9/19 on Cedar Mountain near Big Sky.

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.

A natural avalanche that broke within the new snow on the east face of Mount Blackmore. Photo: G. Antonioli.

Small skier triggered slide in the new snow on Mount Blackmore. Photo: G. Antonioli

From e-mail: "Observed a small slide that appeared to be skier-triggered (tracks entering & exiting) on a wind-loaded, north-facing (21 degrees north) slope, slope angle of approximately 36 degrees." Photo: A. Yount

This crown was observed on 3/3 and likely slid a couple days earlier after steady snowfall and wind. This path had a large avalanche previously this winter in mid-January. Photo: G. Antonioli

This crown was observed on 3/3 and likely slid a couple days earlier after steady snowfall and wind. This is the second time this slopes slid this winter.It had a large avalanche in mid-January. Photo: G. Antonioli

Steady snowfall last week created soft slabs like this natural crown. Photo: G. Antonioli

Cornices are large, and intense spring sun will make them weak and easier to trigger or break naturally. Be cautious along ridgelines and on slopes below these monsters as temperatures warm. Photo: G. Antonioli

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

A skier found reactive wind slabs on the north face of Elephant today. Photo: W. Moore

Skiers reported triggering soft wind slabs in Hyalite on NE aspect at 9000'. Photo: T. Chingas

From an email, "Lots of wind slab activity... tough to tell exactly what happened here with everything filling back in so fast. A few quickly-disappearing crowns on ridge line and throughout E face, good debris pile." Photo: Cody C.

Photo: A. Lussier

A skier wrote, "Large natural avalanche on the south face of peak 10,201. Looked to be a day or two old and the crown looked to be 3-4 feet deep in places." Photo: S. Wilson

A skier noted, "Newish slide with a fresh looking debris pile. Between Alex Lowe and Peak 9806. Appeared to step down into the old snow. Looked like a D2.5-R3, natural trigger." Photo: F. Madsen

Natural avalanche observed on January 28th.

From email: "Fresh natural on east face of Blackmore in gently wind-loaded terrain."

Photo: B. VandenBos

Skiers triggered this avalanche in dense trees while ascending Mt. Ellis. From the email: "While subsequently skiing up through dense trees climbing to the north to attempt to reach the mid section of the going-home chute, a medium-size bowl-shaped opening in the trees released a soft slab just as we were entering the opening. The crown was ~24” deep and ~80-100’ across. Total snow depth in that area was less than three feet. The avalanche ran probably 500 vertical feet down a shallow gully. Neither my partner nor I where caught but way too close for comfort"

Skiers triggered this avalanche in dense trees while ascending Mt. Ellis. From the email: "While subsequently skiing up through dense trees climbing to the north to attempt to reach the mid section of the going-home chute, a medium-size bowl-shaped opening in the trees released a soft slab just as we were entering the opening. The crown was ~24” deep and ~80-100’ across. Total snow depth in that area was less than three feet. The avalanche ran probably 500 vertical feet down a shallow gully. Neither my partner nor I where caught but way too close for comfort." 

Skiers triggered this avalanche in dense trees while ascending Mt. Ellis. From the email: "While subsequently skiing up through dense trees climbing to the north to attempt to reach the mid section of the going-home chute, a medium-size bowl-shaped opening in the trees released a soft slab just as we were entering the opening. The crown was ~24” deep and ~80-100’ across. Total snow depth in that area was less than three feet. The avalanche ran probably 500 vertical feet down a shallow gully. Neither my partner nor I where caught but way too close for comfort."

A skier in Hyalite reported widespread avalanche activity in the Divide drainage. From the email: "Saw this set of crowns just to the looker's left of Divide Peak proper.  Appear to be cornice triggered, I suspect they all released sympathetically, maybe sometime yesterday.  Impressively connected, definite PWL issue. SE aspect. Crowns spanned nearly 1/2 mile of terrain." Photo: B. VandenBos

A skier in Hyalite reported widespread avalanche activity in the Divide drainage. From the email: "Saw this set of crowns just to the looker's left of Divide Peak proper.  Appear to be cornice triggered, I suspect they all released sympathetically, maybe sometime yesterday.  Impressively connected, definite PWL issue. SE aspect. Crowns spanned nearly 1/2 mile of terrain." Photo: B. VandenBos

A skier in Hyalite reported widespread avalanche activity in the Divide drainage. From the email: "Saw this set of crowns just to the looker's left of Divide Peak proper.  Appear to be cornice triggered, I suspect they all released sympathetically, maybe sometime yesterday.  Impressively connected, definite PWL issue. SE aspect. Crowns spanned nearly 1/2 mile of terrain." Photo: B. VandenBos

This avalanche on Wheeler Mountain failed right next to one that occurred on the same slope earlier in the week. Photo: G. Antonioli

Skiers near lick creek intentionally triggered this avalanche that failed below the recent snow. From the email: "Ski cut a wind loaded soft slab on 34 degree headwall dropping into Bozeman Cr. drainage. Slope fractured and ran short ways, 100 feet from crown to toe. Crown was 75 feet across and 20 inches deep." Photo: Kenna

Skiers near lick creek intentionally triggered this avalanche that failed below the recent snow. From the email: "Ski cut a wind loaded soft slab on 34 degree headwall dropping into Bozeman Cr. drainage. Slope fractured and ran short ways, 100 feet from crown to toe. Crown was 75 feet across and 20 inches deep." Photo: Kenna

Crown of avalanche that was triggered by a group of four skiers. Two were partially buried (1 injured, 1 killed) on 1/25/19. They were all ascending and near the top of the path when the avalanche broke. The top two skiers held onto trees as the avalanche pushed by them. Photo: GNFAC

Overview of avalanche path where a group of four skiers were caught, and two were partially buried (1 injured, 1 killed) on 1/25/19. Crown is marked by black line and location of partial burial/deceased is tip of red arrow. The other partially buried skier was 200' lower. They were all ascending and near the top of the path when the avalanche broke. The top two skiers held onto trees as the avalanche pushed by them. Photo: GNFAC

Skiers up the main fork of Hyalite Canyon experienced collapsing and shooting cracks on an east facing slope at 7.300 ft. Photo: M. Tepfer

A skier noticed multiple collapses at History Rock, and snapped a photo of active wind loading at higher elevations in Hyalite. From the email: " Roughly 30cm new snow from the last storm, light winds, although Blackmore (pictured) and Flanders appeared to be getting hammered by the wind. Did a few laps in the top meadow and was getting frequent collapsing on the way back up. One felt like a small earthquake and was the loudest wumpf I've ever heard." Photo: M. Lavery