Regional Conditions for Northern Gallatin

Skiers triggered this avalanche on the north face of Mt. Blackmore on Sunday June 9th. Photo: C. Pruden

Skiers triggered this avalanche on the north face of Mt. Blackmore on Sunday June 9th. Photo: C. Pruden

Natural wet slabs were widespread on Fan Mtn. near Big Sky during the week of 5/13-5/16. Photo: E. Mullen

Natural wet slabs were widespread on Fan Mtn. near Big Sky during the week of 5/13-5/16. Photo: E. Mullen

This natural wet slab slid early this week, Monday (5/13) or early Tuesday (5/14), near Beehive Peak. This photo was taken 0745 Tuesday morning. Photo: @cfirer

This natural wet slab slid early this week, Monday (5/13) or early Tuesday (5/14). Photo: @wallace_casper

Debris from a wet slab that released naturally Tuesday evening on saddle Peak. Debris ran very far into the runout compared to similar sized dry slabs that often occur on this path. "South side of 1/4 Saddle slid sometime last night. Looks like cornice drop then step down to near ground. Hi yesterday at Alpine was 62." -R. Elliott/BBSP

This wet slab released naturally Tuesday evening on saddle Peak. "South side of 1/4 Saddle slid sometime last night. Looks like cornice drop then step down to near ground. Hi yesterday at Alpine was 62." -R. Elliott/BBSP

"South side of the Glide Plane released as a glide avalanche last evening (May 12th) sometime around 6 pm according to source. Bed surface was ground in starting zone of wet clay soil sparsely covered in long grass.  Debris chunks, some snowmobile sized, rode up on surface and slid approx. 200 vert.  Debris could have bumped a tower on the old Alpine lift if it still lived there. Last freeze was 6 am on the 10th of May.  The high temperature on the 12th was 59 degrees at 4 pm." Photo and observations: BBSP

"South side of the Glide Plane released as a glide avalanche last evening (May 12th) sometime around 6 pm according to source. Bed surface was ground in starting zone of wet clay soil sparsely covered in long grass.  Debris chunks, some snowmobile sized, rode up on surface and slid approx. 200 vert.  Debris could have bumped a tower on the old Alpine lift if it still lived there. Last freeze was 6 am on the 10th of May.  The high temperature on the 12th was 59 degrees at 4 pm." Photo and observartions: BBSP

Skiers found fresh wind slabs that were easily triggered on Saturday 4/27 near Beehive Basin in the northern Madison Range. Photo: E. Birkeland

Skiers easily triggered loose snow avalanches of the 3-5” of new snow. This morning (4/27) on the Bridger Ridge. Photo: @smooneyski

Skiers easily triggered loose snow avalanches of the 3-5” of new snow. This morning (4/27) on the Bridger Ridge. Photo: @smooneyski

Link to donate to the Friends of GNFAC: https://www.givebiggv.org/organizations/friends-of-the-gallatin-national-forest-avalanche-center

This slide occurred around 1400hrs on 4/19/19 with sunshine and temps above 50 F. Photo: GNFAC

Activity from 4/19/19. Photo: GNFAC

Activity from 4/19/19. Photo: GNFAC

Skiers saw this crown on Saturday (4/13) in the N. Bridgers. Photo: M. Gaffney

Recent spring snow has created instabilities that are confined to within the new snow. Areas such as ridgelines where fresh drifts form should be approached with caution. Cornices and fresh wind slabs should be avoided after fresh snow and/or strong wind. Photo. M. Gaffney

Photo: GNFAC

From e-mail on 4/11/19: "We found reactive storm slabs and touchy windslabs near ridgelines. We kicked off a small windslab in 4th of July from the top of the couloir. Attached is a photo of the crown to give you a depth perspective. It was about 6 feet across and 3-4 inches deep."

Snowpit dug at Bridger Bowl on Monday (4/8). Heavy snow and rain are creating dangerous avalanche conditions. Photo: BBSP

Below 3-5" of new snow there is a supportable frozen crust on top of a wet snowpack on most slopes. Avalanches are mostly confined to the new snow on top of this crust (wet loose, dry loose, wind slabs). However, where the snowpack did not freeze below the new snow, or when this crust melts, deeper wet slides are possible. Photo: GNFAC

Dry loose, wet loose, and dry slab avalanches on the east face of Mt. Blackmore. Photo: N. Salsburg

A skier in Hyalite found small but easy to trigger wind slabs at upper elevations near Mt. Bole in Hyalite. Photo: C. Kussmaul

A skier in Hyalite found small but easy to trigger wind slabs at upper elevations near Mt. Bole in Hyalite. Photo: C. Kussmaul

Photo: J. Dillon

Skiers in Hyalite saw a natural wet slab near Blackmore Lake. From the email: "The slide was located around 300 yards South of Blackmore Lake on a West facing slope at an elevation just above 7400 feet.  It broke below a cliff band about 3' deep (to the ground) and ran a few hundred feet (almost to the skin track)." Photo: JR Mooney

Skiers triggered this wet slab avalanche on Saturday afternoon (3/23). Warm sunny days have weakened the snowpack and made wet avalanches possible. Photo: G. Egnew

Skiers triggered this wet slab avalanche on Saturday afternoon (3/23). Warm sunny days have weakened the snowpack and made wet avalanches possible. Photo: G. Egnew

This wet slab was observed on Friday (3/22) across the Sourdough canyon trail, about 1.4 miles up. It put 4-6 feet of debris lower down in the creek. Although small, a heavy wet slide like this can be powerful and very dangerous. Current warm temperatures are a shock to the snowpack, and steep slopes should be avoided if the snow is wet. Photo: P. Brown

This wet slab was observed on Friday (3/22) across the Sourdough canyon trail, about 1.4 miles up. It put 4-6 feet of debris lower down in the creek. Although small, a heavy wet slide like this can be powerful and very dangerous. Current warm temperatures are a shock to the snowpack, and steep slopes should be avoided if the snow is wet. Photo: S. Gill

This wet slab was observed on Friday (3/22) across the Sourdough canyon trail, about 1.4 miles up. It put 4-6 feet of debris lower down in the creek. Although small, a heavy wet slide like this can be powerful and very dangerous. Current warm temperatures are a shock to the snowpack, and steep slopes should be avoided if the snow is wet. Photo: S. Gill

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