23-24

Natural Avalanches and Collapsing, Bridgers

Sacajewea Peak
Bridger Range
Code
N
Latitude
45.89580
Longitude
-110.96800
Notes

Skiers and snowmobilers near Fairly Lake saw several recent natural avalanches on Pomp, Sac, and Naya Nuki, that likely happened in the last two days. 

 

Number caught
0
Number buried
0
Trigger
Natural trigger
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

New snow and wind at Fairy Lake

Date
Activity
Snowmobiling

We rode to the the Fairy/Frazier Basin divide today to check out snow conditions and see what people had gotten up to over the weekend.  The new snow had settled to about 4" or so and we did not notice any wind affect at lower elevations on the road but did find some deeper drifts hiding in the lee pockets in the meadows higher up.  The climb up to the divide with Frazier only had 2-3 inches of fresh snow on it, and the saddle was nearly bare.  Under the new snow there is a in places stout crust from the warmup last week (and past wind) which made for unpredictable riding. There were slick spots, breakable spots, and some fresh drifts. The ridge lines all were scoured as expected from the recent wind but we did not see any significant recent avalanche activity in the new snow, only a couple very small pockets had slid near the ridge tops and these were few and far between.  

Region
Bridger Range
Location (from list)
Fairy Lake
Observer Name
K. Marvinney

We dug a snowpit at 9,761' on a west facing slope south of Cooke City. ECTP21, 40 cm below the surface (16" down). There was 6-8" of new snow from the weekend above 4" of soft old snow, on top of 4" of a pencil- hard slab, then the soft sugary facets to the ground. ECT broke below the hard slab at the top of the facets. Photo: GNFAC

Cooke City, 2024-02-05

Widespread Collapsing and Shooting Cracks at Bacon Rind

Bacon Rind
Southern Madison
Code
Latitude
44.96090
Longitude
-111.10000
Notes

The stability at Bacon Rind was very poor, avalanches were likely, and we avoided (and strongly recommend avoiding) avalanche terrain. We triggered booming collapses and watched cracks shoot out across terrain features and snow shake off nearby trees for the entirety of our tour from the meadow near the car to the top of the Skillet. We avoided steeper meadows and gave the "Skillet" (the primary avalanche path where we were) a wide berth because we felt triggering a slide was so likely. 

There was 8" of new snow. The upper half of the snowpack was a slab, and the lower half was airy depth hoar stressed to the point of failure. Snowpit results were ECTP11 and 12 failing 35cm down from the surface. 

Number of slides
0
Number caught
0
Number buried
0
Slab Thickness
35.0 centimeters
Weak Layer Grain type
Depth Hoar
Weak Layer grain size
7.00mm
Weak Layer Hardness
F
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year

Natural Avalanches in Beehive Basin

Beehive Basin
Northern Madison
Code
L-N
Latitude
45.33430
Longitude
-111.38600
Notes

Multiple natural avalanches and at least one suspected human triggered dry loose in Beehive Basin. Most naturals appeared to have run either last night or yesterday (2/3/24), with a couple potentially older slides. New snow and rapidly changing cloud cover/depth perception made it a bit hard to be sure. Suspect one skier trigged dry loose in W facing trees. One of the W-facing chutes further up valley was also observed to have a crown line at approximately 9000' (no photo)

Number of slides
4
Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Natural trigger
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year