Southern Madison

Unstable weak layers in the S Madisons

Date
Activity
Snowmobiling

Clear skies, sunshine and great visibility today allowed us to cover a lot of ground in the Southern Madisons. We traveled up the Taylor Fork to the weather station in Sunlight Basin, over to the head of Carrot Basin, through Sage Basin and up and over into Cub and Cabin Creeks. 

Winds were light all day and only picked up later in the afternoon, gusting moderately from the south in the parking lot. Solar aspects moistened in the upper 1-2" of the snowpack, but we noted minimal signs of wet snow instability.

We came to the Taylor Fork searching for signs of instability from persistent weak layers and wind slabs, and we found both. We saw up to five recent avalanches from the last few days. 1-2 looked to have failed on PWLs, and the rest were wind slabs. Cornice collapses triggered at least two of these avalanches. 

Outside of recent avalanches, a few other red flags jumped out at us. While traversing to our pit site in Sunlight Basin, we triggered a whumpfing collapse and a shooting crack up to 100' long across an adjacent slope. This snowpit on a SE aspect was made up of a dense slab of recent snow, sitting on top of many different layers of junky, faceted grains. Propagation was easy to find (ECTP 11, HS: 112). We also dug snowpits on N and SW facing slopes. While we found weak snow on these slopes, the N (ECTPX) and SW (ECTP25), the snowpack was deeper in both areas and the weak layers were less developed. When compared to what Alex and Mark found three weeks ago in this area, these instabilities are becoming less widespread and more stubborn to trigger, but an avalanche breaking on these weak layers is still possible. 

Region
Southern Madison
Location (from list)
Taylor Fork
Observer Name
Haylee Darby

Wind Slab avalanche at Taylor Fork

Taylor Fork
Southern Madison
Code
HS-N-R1-D1-S
Elevation
8130
Aspect
E
Latitude
45.06070
Longitude
-111.27200
Notes

We rode into the Taylor Fork, down into the bottom of Sunlight Basin, across Carrot Basin and to the Wilderness Boundary.... Additionally, we saw one wind slab avalanche (R1, D1) in Sunlight Basin. This slide was fresh from this morning or yesterday. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
1
D size
1
Bed Surface
S - Avalanche released within new snow
Problem Type
Wind Slab
Slab Thickness
6.0 inches
Vertical Fall
40ft
Slab Width
40.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Cold powder and little else of note

Date
Activity
Skiing

Skied up the southern of the two typical Bacon Rind skintracks (through the more heavily burned area to the upper meadows). Saw no signs of instability (no cracking, collapsing, or recent avalanches).

Dug a pit on an E aspect at 8800 ft in one of the upper meadows. 128 cm snow depth. No propagation in an Extended Column Test. There is weak snow at the ground, but it isn't super well developed or very weak (4 Finger minus hardness).

No wind affect where we traveled today. 

Region
Southern Madison
Location (from list)
Bacon Rind
Observer Name
Ian Hoyer

We rode into the Taylor Fork on Feb 13, down into the bottom of Sunlight Basin, across Carrot Basin and to the Wilderness Boundary. We saw four persistent slab avalanches that likely broke last weekend or at the beginning of the week. All appeared to be snowmobiler-triggered R1-2, D1.5-2 avalanches at broke of the January layer of near-surface facets and surface hoar. Additionally, we saw one wind slab avalanche (R1, D1) in Sunlight Basin. This slide was fresh from this morning or yesterday. Photo: GNFAC

Southern Madison, 2025-02-14

We rode into the Taylor Fork on Feb 13, We saw four persistent slab avalanches that likely broke last weekend or at the beginning of the week. All appeared to be snowmobiler-triggered R1-2, D1.5-2 avalanches at broke of the January layer of near-surface facets and surface hoar. Photo: GNFAC

Southern Madison, 2025-02-14