Regional Conditions for Northern Gallatin

From Obs: "I skied into Maid of the Mist today, it looks like part of a cornice fell and it failed on a wind slab from last weekend’s snow. It did not step down to the depth hoar. Photo: S Reinsel

From obs on 1/23/21: "I observed a couple older (1-2 week) naturals on E/ESE aspects in the Divide basin, and newer (1-3 days) naturals [shown in photo] on the NE side of Divide and an east aspect at the head of the Maid of the Mist basin." Photo: S. Reinsel

From obs on 1/23/21: "I observed a couple older (1-2 week) naturals on E/ESE aspects in the Divide basin, and newer (1-3 days) naturals [shown in photo] on the NE side of Divide and an east aspect at the head of the Maid of the Mist basin." Photo: S. Reinsel

Small, loose snow avalanches on the east face of Mt Blackmore. Photo: B. Richards

Small slab avalanche and wind-loading on the north face of Mt Blackmore. Photo: B. Richards

Winds actively drifting the new snow into unstable slabs. Photo: GNFAC

We looked at the avalanche in Hyalite that was triggered on Saturday 1/9/21. The slope angle was 33-35 degrees on the starting zone of the lookers right path. It broke 2-3’ deep on weak facets below a hard slab, 1000’ wide and the debris was 5-9’ deep. East aspect, 9,800’ elevation. Photo: GNFAC

We looked at the avalanche in Hyalite that was triggered on Saturday 1/9/21. The slope angle was 33-35 degrees. It broke 2-3’ deep on weak facets below a hard slab, 1000’ wide and the debris was 5-9’ deep. East aspect, 9,800’ elevation. Photo: GNFAC

We looked at the avalanche in Hyalite that was triggered on Saturday 1/9/21. It broke 2-3’ deep on weak facets below a hard slab, 1000’ wide. East aspect, 9,800’ elevation. Photo: GNFAC

Skiers triggered this avalanche on Flanders Mountain on 1/9/21. It was triggered out of the photo to the right on a seperate slope around the corner. It propagated over 1000' wide, and 2-4' deep. Photo: GNFAC

Skiers triggered this avalanche on Flanders Mountain on 1/9/21. It was triggered out of the photo to the right on a separate slope around the corner. It propagated over 1000' wide, and 2-4' deep. Photo: GNFAC

Skiers triggered this avalanche on Flanders Mountain on 1/9/21. It was triggered out of the photo to the right on a seperate slope around the corner. It propagated over 1000' wide, and looks to be 6' deep at deepest. Photo: A. Blackmer

Skiers triggered this avalanche on Flanders Mountain on 1/9/21. It propagated around the corner over 1000' wide into an adjacent path.

From obs: "We dug a pit and found a really weak snowpack! Regardless of the poor stability result, we proceeded to ski an East facing bowl south of Flanders Mountain knowing that the slope angle was low and only flirted with 30 degrees in some parts of the bowl.... My partner skied first, he skied practically all the way back to the skin track when the slope failed and the entire bowl released. He was pretty well out of the way of danger by the time the bowl began to move. From our perspective, the trigger happened at the bottom of the slope. The bowl was not the only slope that slid, the avalanche propagated around the ridge and released a slide on the more south-easterly facing aspect just south of the bowl. We tail-tucked and went home glad no one was caught or hurt."

From obs: "I went up Blackmore [1/9/21]... A pit on a south aspect at 9400’ had 100 cm, and failed at ECTP22 on large, loose facets underlying a crust about 50 cm down. A pit on a north aspect at 9400’ had 105 cm and failed at ECTP20 on the same layer, although the crust was close to nonexistent on this aspect. The snowpack overall was weaker and less consolidated here. A pit on an east aspect at 9400’ had 135 cm, and failed at ECTP25 on the same layer as the other two. I experienced a couple collapses while in shallower, treed areas on north and south aspects today. I did not observe any recent natural activity, but do not trust the snow very much."

A skier got a collapse and crack in Lick Creek. The collapse has sizeable displacement which is indicative of a very thick and unstable weak layer. Photo: W. Casper

A backcountry skier wrote, "...observed a fairly large, cornice-triggered avalanche on an east aspect at 9600’ that looked to be several hours old. The crown was 40-100 cm deep, and it looked like it failed about 20 cm into the facets that make up the lower half of the snowpack in this region."

A backcountry skier wrote, "...observed a fairly large, cornice-triggered avalanche on an east aspect at 9600’ that looked to be several hours old. The crown was 40-100 cm deep, and it looked like it failed about 20 cm into the facets that make up the lower half of the snowpack in this region."

From obs: "Skied Mt Blackmore this morning. Very windy up in the basin, but calm along the ridgeline. Lots of signs of wind-loading and drifting on most slopes. I felt/heard 3 collapses while ascending the trees up to the east ridge. Saw a debris pile on the N face, likely from a cornice fall in the last 24hrs." Photo: M. Lavery

From obs: "I did not observe any recent natural activity from the top of Flanders, save for one small slide that started right at a ridgeline. I did not experience any collapsing or cracking, although thinner snow near trees or rocks was weak and unsupportable."

From obs: "Skier triggered a 1.5' slide to his right while making a turn near a cliff band. The slide did not intersect with the skier's path. We did a ECT before choosing our line and were not able to get the soft slab, or anything else to propagate, but clearly, the slab is ready to go as it slid on rocks. We both skied out without incident."

From obs: "Skier Triggered a 1.5' slide to his right while making a turn near a cliff band. The slide did not intersect with the skier's path. We did a ECT before choosing our line and were not able to get the soft slab, or anything else to propagate, but clearly, the slab is ready to go as it slid on rocks. We both skied out without incident."

Crown of a skier triggered avalanche on the Football Field, out of bounds south of Bridger Bowl, on 12/25/2020.

Crown of a skier triggered avalanche on the Football Field, out of bounds south of Bridger Bowl, on 12/25/2020.

Large natural avalanche on an east face in the Divide Cirque. I suspect it failed during the storm on the 22nd as the crown and flanks were obscured. Photo: GNFAC

From email: "Noted one natural crown off Elephant, NW aspect, 9,600', D2 HS, estimated crown depth around 2 feet, appeared several days old." Photo: G. Antonioli

Strong wind over the weekend deposited fresh drifts, about 10" deep, over weak snow. Bridger Bowl ski patrol triggered a few of these drifts on Monday (12/21) during avalanche mitigation. Photo: BBSP

A skier kicked off a larger than expected cornice as they skinned up the ridge on the W side of Beehive basin on Sunday (12/20/20).

From obs.: "Kicked off a larger than expected cornice as we skinned up the ridge on the W side of Beehive basin. Wind was blowing 20-ish across the opening, cornice had grown pretty good-sized for so little snow. I was making a turn on skins to get back away from the edge when the cornice gave way, probably pulled 25 feet end to end and broke a good 5 feet back from the lee edge of the cornice. I was able to get off the cornice and avoid going over the edge. No activity on the slope below after cornice drop,... although there was a decent hard slab that pulled out just below the ridge when the cornice dropped onto it.... Hard slab on the edges was about 10" deep, some big chunks of cornice on the slope for any future riders..."

Natural slide off lower Hyalite Peak. Photo: H. Van Denburg

Small, loose snow avalanche in the Divide Cirque in Hyalite Canyon. These could push a skier into/ off obstacles such as trees and cliffs. Photo: GNFAC

Light wind created soft drifts of new, low density snow near the ridgeline in the Bridger Range. This wind slab easily cracked when touched with skis, 20 feet along the ridge and 5-10 feet down, but didn't slide. This is a sign drifts will be unstable as they grow with more snow and wind. Photo: GNFAC

A skier saw this avalanche get triggered at Bridger Bowl (Schlasmans Lift) this afternoon 12/2/2020. "...The toe of the slide was all of 6’ deep. There is about a foot of fresh sitting on top of faceted crust that is sitting on top of more facets and another crust,..." Photo: Anonymous

Watch the video HERE!

The BBWC (Bridger Bowl Wind Cloud) on Tuesday 10/27 accompanied 50-60 mph gusts. This strong wind drifted recent snow into slabs that could avalanche on steep slopes. Early season snow means we need to be thinking about and managing avalanche hazard when we travel in the mountains. Photo: GNFAC

Skier triggered slide on 10/26 at Bridger Bowl near the top of Pierre's Knob lift. Photo: @taitbigmoneyswan

Skier triggered slide on 10/26 at Bridger Bowl near the top of Pierre's Knob lift. Photo: @taitbigmoneyswan

Wind-drifted snow avalanched naturally in a few areas of the northern ranges yesterday (10/23). This photo was near Fairy Lake in the Bridger Range. Photo: B. VandenBos