Avalanche Details: Many natural avalanches on Mt Blackmore
Northern Gallatin, 2020-02-22
Northern Gallatin
From IG #gnfacobs post: "An avalanche from early Tuesday (02/18) morning caused by a natural cornice fall. Note the step down partway down the path. ENE @ 9700. Ran 1300’." Photo: A. Whitmore
Avalanche Details: Natural Avalanche in Absarokas
Forecast link: GNFAC Avalanche Forecast for Sat Feb 22, 2020
Out of Advisory Area, 2020-02-22
Forecast link: GNFAC Avalanche Forecast for Sat Feb 22, 2020
We saw this crown on an east aspect around 9,000 feet above Blackmore lake on 2/21/20. It likely broke during the weekend of 2/15-2/16, but could be more recent. Photo: GNFAC
Avalanche Details: Many natural avalanches on Mt Blackmore
Northern Gallatin, 2020-02-22
Crown of an avalanche that broke the weekend of 2/14-2/15 on a SE aspect around 9,700' on Mt. Blackmore in Hyalite. Depth was 3-5 feet. Avalanche in background is one of at least seven we saw in this drainage. Photo taken 2/21/20: GNFAC
Avalanche Details: Many natural avalanches on Mt Blackmore
Forecast link: GNFAC Avalanche Forecast for Sat Feb 22, 2020
Northern Gallatin, 2020-02-22
Forecast link: GNFAC Avalanche Forecast for Sat Feb 22, 2020
Crown of an avalanche that broke the weekend of 2/14-2/15 on a SE aspect around 9,700' on Mt. Blackmore in Hyalite. Depth was 3-5 feet. Photo taken 2/21/20: GNFAC
Avalanche Details: Many natural avalanches on Mt Blackmore
Forecast link: GNFAC Avalanche Forecast for Sun Feb 23, 2020
Northern Gallatin, 2020-02-22
Forecast link: GNFAC Avalanche Forecast for Sun Feb 23, 2020
Debris from an avalanche that broke the weekend of 2/14-2/15 on the north face of Mt. Blackmore in Hyalite. Photo taken 2/21/20: GNFAC
Big Deep Slabs in Maid of the Mist, Hyalite
Maid of the Mist
Northern Gallatin
Code
HS-N-R4-D3.5-O
Elevation
9900
Aspect
SE
Aspect Range
E-S
Latitude
45.41640
Longitude
-110.97000
Notes
Skiers saw these deep slabs in Maid of the Mist in Hyalite on 2/21/20. Doug Chabot went to the site on the 2/22.
The avalanches were big and deep. They ran on the facets/depth hoar near the ground. The slide (1&2) ran to their maximum runout.
Aspect: South to East
Elevation: 9900'
Slope Angle: estimated 45+ degrees at the steepest with average of 40 degrees.
Using Google Earth
Crown: 9930'
Toe of Debris: 9316' with a measured Alpha Angle of 16 degrees
- Latitude: 45°24'49.65"N
- Longitude: 110°58'49.04"W
Using picture "4 avalanches..." as reference:
- was 300' wide, 6-8 feet deep
- 1300' wide; it ran from east to south aspect; was 10-12 feet deep; ran 2150' slope distance,
- was 150' wide, 450' slope distance, 4-5 feet deep
- was 250' wide and had a measured Alpha Angle of 26 degrees, 4-5 feet deep and ran 775 slope distance.
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
4
D size
3.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
120.0 inches
Vertical Fall
600ft
Slab Width
1300.00ft
Weak Layer Grain type
Depth Hoar
Images
Attached Videos
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
Natural avalanche in the Maid of the Mist Cirque. Photo taken 2/21/2020. Avalanche appears to have broken earlier in the week.
Photo: R. Phipps
Avalanche Details: Big Deep Slabs in Maid of the Mist, Hyalite
Northern Gallatin, 2020-02-21
Deep slab avalanche in the Maid of the Mist Cirque. Photo taken 2/21/2020. Avalanche likely occurred around a week prior.
Photo: R. Phipps
Avalanche Details: Big Deep Slabs in Maid of the Mist, Hyalite
Forecast link: GNFAC Avalanche Forecast for Sat Feb 22, 2020
Northern Gallatin, 2020-02-21
Forecast link: GNFAC Avalanche Forecast for Sat Feb 22, 2020