23-24

Skiers in the Western Tobacco Roots saw widespread sluffing involving recent storm snow. The skiers triggered one small avalanche that broke 4-6" deep and 30' wide on a wind-loaded slope, D1. Photo: W. Hubbard 

 

 

Out of Advisory Area, 2024-04-18

Tobacco Roots Storm Slab + Dry Loose

Date
Activity
Skiing

Out in the Western Tobacco Roots today. Recent snow was decently wind affected and storm depths were particularly variable. One thing was common with all new snow deposits: they were bonded very poorly to the widespread underlying crust. In most areas the new snow was not cohesive or deep, so this resulted only in tricky skinning and long running sluffs.

However, where wind or sun had strengthened the slab this surface layer was reactive, with sluffs entraining significant amounts of snow and one small slab that I managed to trigger. I popped this slab underneath a mild, somewhat cross-loaded convexity on a north face near treeline, and it broke around 30 feet wide, 4-6 inches deep, and ran ~ 300 feet (N, 9500', SS- ASu - R1/D1).

The underlying snowpack showed no signs of instability, though while boot packing I did break through the crust in some shallower areas and found some basal facets. The snow surface stayed pretty cool throughout the day above 8.5 kft, and winds were light out of the west.

Region
Out of Advisory Area
Location (from list)
Tobacco Root Mountains
Observer Name
Wyatt Hubbard

Dry Loose on Ross Pk.

Ross Peak
Bridger Range
Code
L-AS
Latitude
45.85700
Longitude
-110.95100
Notes

From obs: "Skied the Banana Coulior off Ross today (04/18). 6-8" of fresh, dry snow has fallen and lies above a bomber crust that was observed on all aspects we traveled on. The weak interface between new, dry snow and the pervasive crust allowed for a large sluff, or dry-loose slide, that began near the top of the Banana Coulior and ran for ~ 500'"

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Skier
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Remote trigger in little bear

NORTHERN GALLATIN RANGE
Northern Gallatin
Code
WS-AMr-R3-D2-O
Elevation
8100
Aspect
NE
Latitude
45.48020
Longitude
-111.13200
Notes

From IG message 4/17/24: "Remote trigger up little bear today. Went to the groundish."... "It was definitely wet below the new snow. It was north east facing at 8100 ft"

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Wet slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
30.0 inches
Vertical Fall
200ft
Slab Width
300.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Dry Loose on Ross Pk.

Date
Activity
Skiing

Skied the Banana Coulior off Ross today. 6-8" of fresh, dry snow has fallen and lies above a bomber crust that was observed on all aspects we traveled on. The weak interface between new, dry snow and the pervasive crust allowed for a large sluff, or dry-loose slide, that began near the top of the Banana Coulior and ran for ~ 500'

Region
Bridger Range
Location (from list)
Ross Peak
Observer Name
E. Webb

Remote trigger in little bear

Date
Activity
Snowmobiling

From IG message 4/17/24: "Remote trigger up little bear today. Went to the groundish."

Region
Northern Gallatin
Location (from list)
NORTHERN GALLATIN RANGE
Observer Name
Loren Griswold