Trip Planning for Northern Madison

Toured up to the NE shoulder on Mt. Blackmore yesterday. Winds were strong and variable, but mostly gusting from the S-SW. A lot of snow was moving around, skin tracks were filled in very quickly, and you could actively see small cornices starting to build on the lee side of the ridge. Photo: H. Darby

Saw a group of skiers trigger a small wind slab avalanche on an eastern aspect at around 8,300' in the main fork of Hyalite in "Candy Land" just south of the climb Big League Chew at 2:00pm on Saturday (11/26). Crown looked to be around 2" to 1' and 90' wide. The slide ran maybe 100'. No skiers were caught. Photo: Anon

Saw a group of skiers trigger a small wind slab avalanche on an eastern aspect at around 8,300' in the main fork of Hyalite in "Candy Land" just south of the climb Big League Chew at 2:00pm on Saturday (11/26). Crown looked to be around 2" to 1' and 90' wide. The slide ran maybe 100'. No skiers were caught. Photo: Anon.

From BSSP Observations: "A wind slab triggered near the top of Cold Springs ran down and triggered a persistent slab around constriction level (see pics). This deeper failure occurred about 20cm off the ground at the Oct/Nov interface in a snowpack that was only about 1m deep." Photo BSSP

From BSSP Observations: "A wind slab triggered near the top of Cold Springs ran down and triggered a persistent slab around constriction level (see pics). This deeper failure occurred about 20cm off the ground at the Oct/Nov interface in a snowpack that was only about 1m deep." Photo BSSP

Crown of skier triggered slide at Bridger on 11/27: "NE face. Rollover around 35 degrees mellowing throughout the run. The face had tracks from earlier today before i triggered the slide. I was able to self arrest and stop myself before being carried. The crown was around 20-25 ft wide and the slide ran roughly 100ft downhill before stopping. Both myself and my partner skied away unharmed."

From observations: "The snow was getting warm on my way up 4th of July couloir (pinwheels coming off lookers right wall started around 11:30) top half took a long time due to deep snow so I was suspicious of the pinch. Ski cut it during the descent (12:30p) and set off a wet slide (point release) that picked up quite a bit of steam as it came out the bottom. Big enough to injure/bury a skier." Photo: Anonymous

At 1:30pm on 11/23 I intentionally triggered a fresh drift of snow in a narrow avalanche path along the edge of the north bowl at Bridger. Northeast aspect at 7,600’ elevation. The crown was 6-8” deep consisting of snow that fell today, 20’ wide and ran 250’ vertical. SS-ASc-R2-D1.5-I. Photo: GNFAC

At 1:30pm on 11/23 I intentionally triggered a fresh drift of snow in a narrow avalanche path along the edge of the north bowl at Bridger. Northeast aspect at 7,600’ elevation. The crown was 6-8” deep consisting of snow that fell today, 20’ wide and ran 250’ vertical. SS-ASc-R2-D1.5-I. Photo: GNFAC

Big Sky ski patrol triggered these slides with explosives on 11/22 during routine avalanche mitigation work. The avalanches were hard slabs that averaged 12" deep and broke on a weak layer above a crust on top of snow that fell in October. Photo: BSSP

Big Sky ski patrol triggered these slides with explosives on 11/22 during routine avalanche mitigation work. The avalanches were hard slabs that averaged 12" deep and broke on a weak layer above a crust on top of snow that fell in October. Photo: BSSP

From IG message: "We saw a few decent sized point releases in the same zone on Sunday, 11/20, the day after the wind slab. All occurred on SW aspect within approx 15 min at 2:30. The air temp rose noteably shortly before and the sun was baking the SW aspect. Wind slab from 11/19 is on the far right, two point releases on the left". Photo: M. Zenker

Toured into divide basin on Friday. Looking at the north face of hyalite peak we saw a slide that went to the ground, and was about 150 feet wide. It possible this slide propagated further, but severe wind loading was actively occurring and it was hard to tell if the crown had been filled back in. We dug a pit at 9300 feet on a SÉ aspect and found a 80-100 cm HS and right side up snow pack with minor faceting below a crust 30 cm from the bottom. 

This natural avalanche of wind blown snow narrowly missed hitting two skiers.

Photo: Anonymous

Photo: @M. Stem

From obs: "Skied Hyalite Peak today and found a wind slab ~10cm deep. Ski cut a small cornice below the main face and broke a small slide that carried ~20’ with little energy with a ~25’ wide crown" Photo: C. Crowe

From obs: "Photos of a small wind slab avalanche (R1 D1)  from yesterday at approximately 7800 feet on the northern end of bradleys meadow. The slide was initiated by the second skier and although the rest of the slope was <30 degrees the starting zone was a NE facing steep cross loaded wind pillow just below the ridge. 

As my friend was skiing down he saw a crack propagate up and to his left and was able to stop on the side of the path as the snow ran past him. The  crown was approximately 30-40 feet and ran about 100 feet." Photo: G. Roe

From IG: "Remotely skier trigger wind slab up on white worm near sac bowl". Photo: C. Howell

While traveling up the Fairy Lake road, we observed the aftermath of an avalanche in October Bowl. The avalanche was D2-D3, start zone was at approximately 9000 ft, north east aspect, crown depth and width is unknown. Photo: H. Bigos-Lowe

Skiers found a thin snowpack that is beginning to weaken (facet). Read observation here. Photo: T McCutcheon.

Skiers in Beehive Basin noted small wind drifts forming as they toured. Slopes loaded by wind-drifted snow are the most likely place to trigger an avalanche right now. Photo: C Ellingson

The Headwaters Snow Stake at Big Sky Resort was buried in new snow on Sunday. 

Evidence of wind-loading creating the conditions for avalanches in the Bridger Range. Cracking is an indicator of instability. The observer noted this was "Nothing consequential," but this shows that unstable drifts are forming. They will be more consequential where there is more snow and as the wind creates larger drifts. Photo: E Smith