Northern Gallatin

A skier was skinning uphill, breaking trail and triggered this avalanche on 1/19/20. They reported, " released a small pocket near texas meadow. Maybe 50 ft wide, 2 ft crown and ran 150 ft....I was not caught and nobody was buried or injured. I was skinning up at about 1130...I got to where it was steeper and as I reached thinner snow near rocks I felt a whump. I took one more step and the pocket released."

Bridger Range, 2020-01-20

Skier triggered small slide Mount Wheeler

Wheeler Mountain
Northern Gallatin
Code
SS-AS-R1-D1.5-O
Latitude
45.50970
Longitude
-111.08200
Notes

From obs: "Skied into to a pillow of snow. I think it started as just sluff but then broke off an avalanche. It was not wide but the crown is estimated at 2 feet. It was not moving fast and I just dug into the bed surface and slowly moved out of it. I was the second skier. The first skiers track did not go as deep as mine. failed on weak facets at the base of a steep roll over."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
R size
1
D size
1.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Avalanche triggered by skiers on Flander's peak in Hyalite on 1/18/20. Nobody caught or buried, but they were surprised and it covered another groups skin track. Photo: J. Riedel

Northern Gallatin, 2020-01-19

Skiers triggered 2 large slides Flanders Mtn.

Flanders Creek
Northern Gallatin
Code
HS-ASu-R3-D2-O
Elevation
9800
Aspect
NE
Latitude
45.43510
Longitude
-110.94400
Notes

From Obs: "... Our party of two was ascending southwest on a rib with the intention of reaching the ridgeline. At 9800', the upper member of our party triggered a D2.5 with an approximately 100' crown immediately to our south. Crown height appeared 2-3' and the slide traveled approximately a distance of 2,000' and 500 vertical feet down mountain. Within a few seconds, we remote triggered to the north a D3 with an approximately 200' crown. Crown height appeared up to 7' at highest point and slide traveled approximately 300 vertical feet down mountain. The remote triggered slide started approximately 15-20 feet to the north of the location of the lower member of our party, who was approximately 30 vertical feet below the upper member of our party. After the slide the upper member of our party noticed a shooting crack at his elevation. Two skiers and one dog were ascending below us. They observed the avalanche and later mentioned that they were approximately 150 feet in distance from the toe of the remote triggered slide, which completely covered their skintrack. Nobody caught or buried."

From group that was below: "Finished a snow pit at 45.434589, -110.940957. Results were ECT-X, Aspect: 110 deg, Angle: 27 degrees, Depth: 90 cm, Weak layer was above melt/freeze at 60 cm, fist hardness above 62 - 67 cm. Then fairly cohesive newer snow 70 - 90 cm. Weak layer did not budge, even when levered with the shovel.

Knowing there was one party of two ahead of us, we continued to 45.434716, -110.94124 when they triggered slide above. It ran through one of the avalanche paths behind us, that we had crossed. We whooped to see if someone was the trigger and if they were ok, they yelled back all was ok. Our mistake was assuming the party ahead was taking, what we consider to be, the standard route up Flanders, not the subtle ridge that we figured was loaded by the month of west/sw winds We were wrong and were traveling below them but still were traveling in the older trees and not in slide paths, yet another example of why you follow protocol. Anyways I took a bunch of pics. Pin on map is about where they triggered it."

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
36.0 inches
Vertical Fall
1500ft
Slab Width
200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Skier triggered Avalanche north of Divide Peak.

Divide Peak
Northern Gallatin
Code
SS-ASc-R2-D2-U
Elevation
9600
Aspect Range
E-SE
Latitude
45.40540
Longitude
-110.97500
Notes

From obs: "There is a small east facing basin that’s between Divide Peak and Maid of the Mist Basin. While walking along the ridge that connects the two, my partner intentionally broke off a large piece of a cornice, which then triggered two substantially sized avalanches in the basin below. The first avalanche was directly beneath the collapsed cornice with a crown 6-12 inches deep and about 30 ft across. The second avalanche was triggered by the 1st avalanche and had a crown of similar depth but was substantially larger. It was hard to see as the crown travelled uphill and around a corner. The ascpet was E and SE, at the elevation of 9,600ft. The pictures I got are poor, but should give you an idea of the size."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
2
D size
2
Bed Surface
U - Unknown
Problem Type
Wind-Drifted Snow
Slab Thickness
12.0 inches
Slab Width
30.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From obs: "There is a small east facing basin that’s between Divide Peak and Maid of the Mist Basin. While walking along the ridge that connects the two, my partner intentionally broke off a large piece of a cornice, which then triggered two substantially sized avalanches in the basin below. The first avalanche was directly beneath the collapsed cornice with a crown 6-12 inches deep and about 30 ft across. The second avalanche was triggered by the 1st avalanche and had a crown of similar depth but was substantially larger.

Northern Gallatin, 2020-01-18