NE facing IP snowpit
24-25
Widespread weak layer Island Park
Date
Activity
Snowmobiling
The old snow surface from the first two weeks of dry weather in December is the main weak layer in the snowpack. It is easy to find on all slopes just under the new snow and two crusts. It's generally buried about a 12-14 inches deep.
We got a range of test scores (mostly bad) of ECTP2, ECTP3, ECTP13, and ECTN. We experienced a few collapses, but it was not widespread. No cracking.
Avalanches - we got above the clouds into the sun and could only spot one avalanche looking towards Mt Jefferson in Rock Creek
My gut says that avalanches aren't too easy to trigger; HOWEVER, all the signs are there and can't be ignored. Some collapsing. A prominent weak layer of facets. Mostly poor test scores, recent loading (1.5-2" of water), and one fresh avalanche.
For those reasons we rode like the danger was CONSIDERABLE....which it was.
Riding and coverage is quickly improving. Above 9000 ft, there's a decent base under the weak layer. Rocks and stumps are still easy to find and we were bumping them all day long.
Region
Island Park
Location (from list)
Yale Creek
Observer Name
Staples
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
2 Storm Slabs near Buck Ridge
Buck Ridge
Northern Madison
Code
SS-N-R2-D2
Latitude
45.17190
Longitude
-111.38000
Notes
We saw two avalanches while riding along Buck Ridge on 12/17. These likely broke overnight on 12/16. 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 similar, but smaller slide in 3rd Yellowmule (~100 ft wide and ran ~200 vertical ft).
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Vertical Fall
500ft
Slab Width
200.00ft
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
Remotely triggered slide near Buck Ridge
Buck Ridge
Northern Madison
Code
SS-AMr-R2-D1
Elevation
9200
Aspect
N
Aspect Range
N-E
Latitude
45.17190
Longitude
-111.38000
Notes
We remotely triggered a slide in upper Bear Creek 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).
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
2
D size
1
Problem Type
Persistent Slab
Slab Thickness
18.0 inches
Vertical Fall
15ft
Slab Width
200.00ft
Weak Layer Grain type
Faceted Crystals
Weak Layer grain size
2.00mm
Weak Layer Hardness
F
Images
Attached Videos
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
Avalanche Details: Remotely triggered slide near Buck Ridge
Northern Madison, 2024-12-17
A natural storm slab avalanche in 3rd Yellowmule (~100 ft wide and ran ~200 vertical ft). Broke either 12/16 or early morning 12/17. Photo taken 12/17/24. Photo: GNFAC
Avalanche Details: 2 Storm Slabs near Buck Ridge
Forecast link: GNFAC Avalanche Forecast for Wed Dec 18, 2024
Northern Madison, 2024-12-17
Forecast link: GNFAC Avalanche Forecast for Wed Dec 18, 2024