This surface hoar crystal is almost 1.5 cm (each square is 2mm) and was the weak layer in a few avalanches on Buck Ridge (3/29/20). Photo: GNFAC
Northern Gallatin
There were many tracks in Buck Ridge and only a few small slides in First Yellowmule. This picture is looking SW towards Sphinx Mountain. Feathery crystals of surface hoar are buried 1-1.5' under the surface and are a concern. This layer seems to be more prevalent in protected areas. Photo: GNFAC
We saw this natural avalanche from afar. It was NE aspect and likely failed on a layer of surface hoar 1-1.5' deep. The Madison Valley is in the background. Photo: GNFAC
Avalanche Details: Natural avalanche near Cedar Mtn.
Forecast link: GNFAC Avalanche Forecast for Tue Mar 31, 2020
Northern Madison, 2020-03-30
Forecast link: GNFAC Avalanche Forecast for Tue Mar 31, 2020
From obs (3/29/20): "...in Maid of the Mist basin there were multiple loose wet avalanches [and a slab] caused by a piece of the cornice falling off on Pt. 10201." Photo: N. Salsburg
Avalanche Details: Natural cornice triggered in Maid of the Mist basin
Northern Gallatin, 2020-03-30
From obs (3/29/20): "On our approach to Maid of the Mist, my partner and I watched several small point release avalanches on the east face of Palace Butte..." Photo: N. Salsburg
Forecast link: GNFAC Avalanche Forecast for Mon Mar 30, 2020
Natural cornice triggered in Maid of the Mist basin
Maid of the Mist
Northern Gallatin
Code
SS-NC-R1-D2-I
Elevation
10000
Aspect
E
Latitude
45.41110
Longitude
-110.98800
Notes
From obs. (3/29/20): "Significant wind started building mid morning, forming even bigger cornices and wind loading many slopes. Noticed this slide on an East/Northeast aspect at the back of the bowl above Maid of the Mist creek, possibly triggered by cornice fall but unknown. Happened between 9:45am and 11:30am today, as at 9:30am it was not there, and when we returned to the spot around 11:30am the slide was visible." Photo: CP
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Cornice fall
R size
1
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
12.0 inches
Vertical Fall
350ft
Slab Width
50.00ft
Images
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
From obs. (3/29/20): "Significant wind started building mid morning, forming even bigger cornices and wind loading many slopes. Noticed this slide on an East/Northeast aspect at the back of the bowl above Maid of the Mist creek, possibly triggered by cornice fall but unknown. Happened between 9:45am and 11:30am today, as at 9:30am it was not there, and when we returned to the spot around 11:30am the slide was visible." Photo: CP
Skier triggered slide in Twin Falls Basin
Hyalite - main fork
Northern Gallatin
Code
SS-ASu-R2-D2
Elevation
9000
Aspect
N
Latitude
45.41740
Longitude
-110.98900
Notes
From obs: Small D2 avalanche triggered while assessing the slope on a due-north facing aspect on a roughly 35-40 deg. slope at ~9000 ft. near Arden Lake in the Twin Falls drainage off the Main Fork of Hyalite. .... Had about a 2 ft deep, 30 ft-long crown. The bed surface was not clearly a sun-crust and was of low quality and remained relatively soft to ski on after the slide. There were crystals above that may be classified as facets, maybe 1mm dia. It seemed to have gone on a compacted layer that the 18" of fresh had weighted."
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
2
D size
2
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
Main Fork of Hyalite 3/27.
From obs: "This slide popped on a N aspect at 9000', ranging from 18-30 inches deep... it slid on a crust." Photo: N. Iltis
Avalanche Details: Skier triggered slide in Twin Falls Basin
Forecast link: GNFAC Avalanche Forecast for Sat Mar 28, 2020GNFAC Avalanche Forecast for Sun Mar 29, 2020
Northern Gallatin, 2020-03-28
Forecast link: GNFAC Avalanche Forecast for Sat Mar 28, 2020GNFAC Avalanche Forecast for Sun Mar 29, 2020
Natural and skier triggered slides in Hyalite
Divide Peak
Northern Gallatin
Code
SS
Latitude
45.40290
Longitude
-110.97600
Notes
From obs: "Later in the day we ran across what we assume to be a remotely triggered avalanche from another party in the area. There were two sets of tracks on the adjacent slope with cracks visible on the slope. The avalanche occurred on a 40* east aspect at 9250' and failed on the MFcr/FC dn 35cm. .... Skiing out the trail with better light than in the morning, we saw a number of similar avalanches confined to east aspects on steep 40*+ rolls and presumably failing on the persistent grains above the crust."
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year