18-19

Natural Avalanches Around Cooke City

Miller Ridge
Cooke City
Code
SS-N-R1-D2-O
Elevation
10000
Aspect Range
E-NE
Latitude
45.04700
Longitude
-109.97600
Notes

A skier reported recent natural slab avalanches on Miller Mtn. near Cooke City. They failed on E-NE aspects just below 10,000'. Another group saw a recent wind slab avalanche on the east face of Mineral Mtn (R1D1.5). A third group sent in a video of a powder cloud from a natural avalanche on Barronette Peak. Photo: B. Fredlund, Video: J. Hodges

Multiple Avalanches
Number of slides
4
Number caught
0
Number buried
0
Number killed
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
1
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Natural Saddle west side

Bostwick Creek
Bridger Range
Code
HS-N-R3-D3.5-O
Elevation
8800
Aspect
NW
Latitude
45.79640
Longitude
-110.93800
Notes

From BBSP on 3/2/19: "Large natural avalanche pulled out last night/early morning on the backside of north peak of saddle peak in Bostwick canyon, the slide path is known as the 'Y' to local skiers and hasn't run this year, or been skied. Crowns looked to be 3-6ft, it ran further than anything i've seen there in the past decade, knocking over small trees and some old standing dead in the run out. R3 D3.5." 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
3.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

From BBSP on 3/2/19: "Large natural avalanche pulled out last night/early morning on the backside of north peak of saddle peak in Bostwick canyon, the slide path is known as the 'Y' to local skiers and hasn't run this year, or been skied. Crowns looked to be 3-6ft, it ran further than anything i've seen there in the past decade, knocking over small trees and some old standing dead in the run out. R3 D3.5." Photo: BBSP

Bridger Range, 2019-03-03

From BBSP on 3/2/19: "Large natural avalanche pulled out last night/early morning on the backside of north peak of saddle peak in Bostwick canyon, the slide path is known as the 'Y' to local skiers and hasn't run this year, or been skied. Crowns looked to be 3-6ft, it ran further than anything i've seen there in the past decade, knocking over small trees and some old standing dead in the run out. R3 D3.5." Photo: BBSP

Avalanche Details: Natural Saddle west side
Bridger Range, 2019-03-03

Deepest part of crown from slide triggered 3/2 by the YC Ski Patrol conducted avalanche mitigation work above one of their roads. A 2lb explosives charge was detonated from an aerial tram and triggered a R4/D3 avalanche that ran to the ground on depth hoar. The crown was 4', The max path width was around 250', and it ran 350 vertical feet to the bottom of the runout zone. The elevation was 8400' on a ENE aspect and max slope angle of 36 degrees. Photos courtesy YC Ski Patrol.

Northern Madison, 2019-03-03

Large explosive triggered slide at Y.C.

Yellowstone Club
Northern Madison
Code
HS-ABc-R4-D3-G
Elevation
8400
Aspect
NE
Latitude
45.23510
Longitude
-111.44800
Notes

From YCSP: "Today the YC Ski Patrol conducted avalanche mitigation work above one of our roads. The area is outside of our ski area boundary and receives no skier traffic. A 2lb explosives charge was detonated from an aerial tram and triggered a R4/D3 avalanche that ran to the ground on depth hoar. The crown was 4', The max path width was around 250', and it ran 350 vertical feet to the bottom of the runout zone. The elevation was 8400' on a ENE aspect and max slope angle of 36 degrees. Two sections of road, which were controlled for traffic, were buried with an estimated 15-20 feet deep deposition pile. We’ve seen this path go big in the Spring, but we can’t recall it ever going quite this big."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
An explosive detonated above the snow surface (air blast)
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
4
D size
3
Bed Surface
G - Ground
Problem Type
Deep Persistent Slab
Slab Thickness
48.0 inches
Vertical Fall
350ft
Slab Width
250.00ft
Weak Layer Grain type
Depth Hoar
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Today the YC Ski Patrol conducted avalanche mitigation work above one of our roads. The area is outside of our ski area boundary and receives no skier traffic. A 2lb explosives charge was detonated from an aerial tram and triggered a R4/D3 avalanche that ran to the ground on depth hoar. The crown was 4', The max path width was around 250', and it ran 350 vertical feet to the bottom of the runout zone. The elevation was 8400' on a ENE aspect and max slope angle of 36 degrees.

Northern Madison, 2019-03-03