Trip Planning for Northern Gallatin

Ridge line just west of divide peak in Hyalite canyon. Photo: O Silitch

Saw a fairly fresh avalanche up Hyalite from the top of the Fat and Skinny Maids, I think that would put the avalanche in the Storm Castle Creek basin. Photo: F Miller

Pictures of two cornice triggered avalanches way up the South Cottonwood drainage that was viewed from Alex Lowe. Looks to be in the recent days, around 9,000 feet North facing. Photo: S Lipsteuer

A massive cornice had cracked and was slowly making its way towards falling down. Cornice was around 50 feet long, and largely overhanging. Photo: S Lipsteuer

A massive cornice that has cracked and is slowly making its way towards falling down. Cornice was around 50 feet long, and largely overhanging. On the standard ascent of the East Ridge of Alex Lowe, the skin track usually travels below this cornice while ascending to the ridge. Photo S Lipsteuer

This older wet slide is a good example of what to look out for especially at low elevations.

This older wet slide is a good example of what to look out for especially at low elevations.

Cornice release above the headwaters of storm castle creek which triggered a slab, east facing aspect.  Looked to be several feet deep and ran a long way.

Cornice triggered slab avalanche, maybe wind slab. Hard to say.

Total snow depth on a NE aspect was 230 cm (7.5 ft). Right side up and strong. Dust layer from Feb 4th was 70 cm deep (28 inches) with no facets under it. 

Clean up on aisle hyalite!  Couple small wet slides between the retaining wall and practice rock, big enough to reduce the road to one lane. Photo: K. Marvinney

From obs.: "Saw a recent cornice triggered wind slab off of Hardscrabble Peak, crown looked fairly fresh. There was a second crown line below the rock band. Conditions were very windy, with snow still being transported. Most snow surfaces were wind affected, but saw no cracking or collapsing." Photo: F. Miller

From obs: "2/17 Immediately noticed signs of wind loading and wind slabs on NE-E aspects once in the basin. New cornices have formed in the last couple days along the North ridge to the summit. Cornice collapse on the summit triggered a small wind slab on an isolated slope." Photo: R. Rintala

From obs: "2/17 Immediately noticed signs of wind loading and wind slabs on NE-E aspects once in the basin. New cornices have formed in the last couple days along the North ridge to the summit. Cornice collapse on the summit triggered a small wind slab on an isolated slope." Photo: R. Rintala

SS-ASc-R1-D.5-I 

310 Degrees  NW

8129ft

Photo: Tagg Cole

Storm slab avalanche between Blackmore and Elephant. Photo: Anonymous

Saw a small natural slide that started at the bottom of Cyptorchid. Crown was 10' wide and 8-18" deep, it ran 150' down a very shallow slope and covered the climbers trail. Photo: R Beck

Saw a small natural slide that started at the bottom of Cyptorchid. Crown was 10' wide and 8-18" deep, it ran 150' down a very shallow slope and covered the climbers trail. Photo: R Beck 

Triggered a small wind slab avalanche on the east face of mt Blackmore today at 9850 ft elevation. Around 5 inches thick, ~ 20 ft wide, and ran for 100 ft. Photo: I Masi

Triggered a small wind slab avalanche on the east face of mt Blackmore today at 9850 ft elevation. Around 5 inches thick, ~ 20 ft wide, and ran for 100 ft. Photo: I Masi

Cold temps and sunny days starting to create some surface hoar forming seen on the primary ridge of big Ellis. Surface hoar was less widely distributed on the primary ski zone but was present all along the top of the ridge. Photo: K Gordon 

I went skate skiing up Sourdough Canyon today. The trail intersects many south and southwest-facing avalanche terrains that generally do not have much snow coverage due to their exposure to the sun. 

However, the snowpack is much deeper than normal in the Gallatin Valley and in the low-elevation mountains around the Valley, and these slopes make me nervous, especially because they would impact a trail that sees heavy use by people who do not intend to expose themselves to avalanches and who are not prepared for avalanche rescue. 

Currently, 2.5 to 4 feet of snow is in the terrain near the trail. 

Photo: GNFAC

I went skate skiing up Sourdough Canyon today. The trail intersects many south and southwest-facing avalanche terrains that generally do not have much snow coverage due to their exposure to the sun. 

However, the snowpack is much deeper than normal in the Gallatin Valley and in the low-elevation mountains around the Valley, and these slopes make me nervous, especially because they would impact a trail that sees heavy use by people who do not intend to expose themselves to avalanches and who are not prepared for avalanche rescue. 

Photo: GNFAC

At the base of G2 I triggered a 3 inch x 100 foot soft slab. Photo: D Chabot

Most notable test result was ECTP16 down 35 cm on a layer of surface hoar. Photo: E Heiman

Most notable test result was ECTP16 down 35 cm on a layer of surface hoar. Photo: E Heiman

Three to four inches of new snow from yesterday sat on top of the dust layer that got deposited across most of the forecast area on Monday and Tuesday. Photo: GNFAC

There was evidence of several R1-2/ D1-2 wind slab avalanches that likely ran this weekend on the east face of Blackmore. Photo: GNFAC

Elephant Mountain and the summer trail area were scoured down to the tundra. Photo: GNFAC

I went for a walk up the main fork of hyalite today and observed a very dirty snow surface from the strong SW winds. Photo: Anonymous

 The cornices are growing rather large from the recent wind. Photo: Anonymous

Lots of wind transport filling in the skin track between laps and creating light reactive slabs ~5” deep in places (see photo) primarily out of the west but generally inconsistent in direction. Photo: E Kiesz

From obs: "Wind was rocking in alpine today, fresh windslabs forming and naturally releasing. I could make out 3 on E face, but rough vis with blowing snow. Exposed terrain in alpine had about .5” ice crust from yesterday’s sunshine.

This slab (in pic) released around 11-noon-ish." Photo taken 1/31/25

Large surface hoar across a variety of elevations and aspects at Lick Creek. It was 2-5mm large and present on almost all flats and non-solar aspects. Photo: W Hubbard 

Crown of a wind slab avalanche from the saddle of Blackmore. Photo: Anonymous

I skied forward maybe 5 feet and broke off a wind slab around 20 feet wide and five feet below me. Shifting my weight right after that the snow below me also broke and slid away. Photo: Anonymous

I broke off a wind slab around 20 feet wide and five feet below me. Shifting my weight right after that the snow below me also broke and slid away. Photo: Anonymous

A wind slab avalanche on east facing slope in hyalite. Photo: D Moeser

Very touchy storm slabs formed throughout the day. 6-8” deep by 3pm. low density snow/slab but very fast moving.Photo: R Griffiths