24-25

Remotely triggered slide

Date
Activity
Snowmobiling

Rode along Buck Ridge, through 1st, 2nd, and 3rd Yellowmules, with good views across Buck Creek and into McAtee Basin. New snow depth increased as we rode from the parking lot to the top of Beaver Creek, from ~4" to 12". We measured 12" of new snow with 0.7" SWE in 1st Yellowmule.  We saw two avalanches. One was a storm slab avalanche on the far (southwest) side of Buck Creek - broke 2-300 ft wide and ran ~500 vertical feet. The other was a smaller slide in 3rd Yellowmule (~100 ft wide and ran ~200 vertical ft). There was not much wind effect.

We crossed through the head of McAtee Basin into upper Bear Creek. While riding on a low angle ridgeline, we remotely triggered a slide that broke approximately 200 ft away in a gully. It failed ~18" deep on facets underneath the snow that has accumulated since Sunday. It broke in several pockets, totaling around 200 ft wide. There was 12" of new snow at the crown, with 0.7" SWE. The slab contained 1.4" SWE total (which accumulated since Sunday). 

Before triggering the slide we experienced no cracking, collapsing, or other clear signs of instability. 

Region
Northern Madison
Location (from list)
Buck Ridge
Observer Name
Ian Hoyer

Lick creek obs

Date
Activity
Skiing

Dug a pit on the east facing slope around 7800'. The snow was 60 cm deep. We got ECTN11 and CT12 RP 15cm down on the old/new snow interface, ECTN16 25cm and CT19 25cm down on a crust.

Also dug a hand pit on a south slope at 6800' to test the new snow and it didn't break easily or cleanly.

We didn't observe any whumphing or cracking.

Region
Northern Gallatin
Location (from list)
Lick Creek
Observer Name
Heather Myers

Wind/storm slab avalanche in the Bridger Range

Ross Peak
Bridger Range
Code
SS-ASc-R2-D2-I
Elevation
8300
Aspect
NE
Latitude
45.85860
Longitude
-110.95600
Notes

Triggered a small slide (r2 d2) in a north east facing chute at around 8300 ft. The slide was triggered on a ski cut through a wind loaded drift and propagated about 15 or 20 ft wide. It about 6 in deep on the edges and two feet in the loaded area. We observed several other signs of instability throughout the day, most wind loaded terrain was touchy and easy to rip off with slabs anywhere from 6 in deep to two or three feet deep. All signs of instability originated from the interface between the new snow from the last few days and facets from the last high pressure system. 

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
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
24.0 inches
Slab Width
20.00ft
Images
Wind/storm slab avalanche 1
Snow Observation Source
Wind/storm slab avalanche
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
24-25
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