23-24

Collapsing around Cooke City

Date
Activity
Skiing

We skied onto the debris of the Henderson Mountain avalanche. It went as wide as it could and broke under the dense wind slab on facets (not surface hoar). We dug in the flank at about 10,100' to confirm that it released on facets under a wind slab. Afterward we skied over to Daisy Pass and had numerous large, thunderous whumps, both there and back. At Daisy Pass/Chimney Rock avalanche (from 1/25) we had poor visibility and could not see the debris or paths. I skied out looking for signs, but decided that wandering in runout zones with no visibility was a bad idea, so we returned back to the sleds on Henderson Bench.

Region
Cooke City
Location (from list)
Henderson Mountain
Observer Name
Doug Chabot

Collapsing weak layers on bighorn pass trail area

Date
Activity
Skiing

30+ whumps on any slope with wind slab deeper than 5”. Happened on slopes from 0-30 degrees stayed off of and away from anything steeper. 

Region
Southern Gallatin
Location (from list)
Fawn Pass
Observer Name
Ryan Van Sluytman

Avalanche off Bridger Peak

Date
Activity
Skiing

 Slide triggered from above (ridge line) onto east facing slide path on Bridger Ridge. Knocked off microwave-sized cornice while skinning which fell and triggered the slope below. We had zero intention of skiing that slope or any like it on todays tour. Slide seemed to start very slowly and then propagated North (to the left in the pictures) before running down the slide path. Looking at the slope no parties or individuals were present around us or in the run out to the best of our observations. Not surprised by the instability at play and yet another reason to heed to the forecast. 

Region
Bridger Range
Location (from list)
Bridger Peak

Explosive triggered slab on facets, BBSP

BRIDGER RANGE
Bridger Range
Code
AEc-R2-D2-O
Elevation
8500
Aspect
NE
Latitude
45.85120
Longitude
-110.94800
Notes

From BBSP: "a jug of ANFO released an R2D2 avalanche that was 16" deep and 150ft wide that ran down to near the upper gate traverse level. It broke on the basal crust that had 4mm facets above."

Number of slides
1
Number caught
0
Number buried
0
Trigger
An explosive thrown or placed on or under the snow surface by hand
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
16.0 inches
Slab Width
150.00ft
Weak Layer Grain type
Faceted Crystals
Weak Layer grain size
4.00mm
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year