Northern Gallatin

Photo taken from Silken Falls

Date
Activity
Ice Climbing

You guys probably already know about this one, but if not then here’s a photo of what appeared to be a natural D2 underneath the Maid today.

Region
Northern Gallatin
Observer Name
Henry Coppolillo

Little Mt. Ellis

Date
Activity
Skiing

At 6450 feet on a north facing aspect on Little Mt. Ellis I found a snow depth of 75 cm. I dug a pit and got a Ct -7. Ect - 18, both failing on ground facets at 15-20 cm depth. I didn’t see any slides, but I did feel and hear one whumpf on the way up. Needless to say, I kept it low angle on the way down. Hope you can use this data. Thanks for all the great work you do!

Region
Northern Gallatin
Location (from list)
Mt Ellis
Observer Name
Rodney Claiborne

Very Large, Natural Avalanches Divide Basin

Divide Peak
Northern Gallatin
Code
HS-R4-D3
Elevation
9800
Aspect Range
S-E
Latitude
45.39250
Longitude
-110.97600
Notes

From Obs: "I skied around the little hills in the basin south of Divide Peak today, and saw quite a bit of recent activity. The southwest corner of Divide Cirque slid on the storm slab and broke 1200-1500’ wide, an east aspect had a crown that exceeded 6’ in places, and the south side of Divide broke 2-6’ deep and ran full track. Things up high are active. I observed no collapsing or cracking, but the signs of instability were still pretty clear"

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
R size
4
D size
3
Problem Type
Persistent Weak Layer
Slab Thickness
72.0 inches
Vertical Fall
650ft
Slab Width
1200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

From obs: "The southwest corner of the cirque slid on the storm slab and broke 1200-1500’ wide, an east aspect had a crown that exceeded 6’ in places, and the south face of Divide Peak broke 2-6’ deep and ran full track. I observed no collapsing or cracking, but the signs of instability were still pretty clear." Photo: S Reinsel

Northern Gallatin, 2021-02-15

From obs: "The southwest corner of the cirque slid on the storm slab and broke 1200-1500’ wide, an east aspect had a crown that exceeded 6’ in places, and the south side of Divide broke 2-6’ deep and ran full track. I observed no collapsing or cracking, but the signs of instability were still pretty clear." Photo: S Reinsel

Northern Gallatin, 2021-02-15

From obs: "The southwest corner of the cirque slid on the storm slab and broke 1200-1500’ wide, an east aspect had a crown that exceeded 6’ in places, and the south side of Divide broke 2-6’ deep and ran full track. I observed no collapsing or cracking, but the signs of instability were still pretty clear." Photo: S Reinsel

Northern Gallatin, 2021-02-15

Divide Basin

Date
Activity
Skiing

I skied around the little hills in the basin south of Divide Peak today, and saw quite a bit of recent activity. The southwest corner of the cirque slid on the storm slab and broke 1200-1500’ wide, an east aspect had a crown that exceeded 6’ in places, and the south side of Divide broke 2-6’ deep and ran full track. I am not sure what the bigger slides failed on, and would not feel particularly confident guessing, but things up high are active. We dug a pit on the south side of Palace Butte on Saturday and found what appeared to be a very stable snowpack, but seeing Divide slide on the same aspect is evidence that a snowpit is only part of the puzzle. I observed no collapsing or cracking, but the signs of instability were still pretty clear.

Region
Northern Gallatin
Location (from list)
Divide Peak
Observer Name
Sam Reinsel

Splitboarder triggered, caught and killed in Beehive

Beehive Basin
Northern Madison
Code
HS-ARu-R4-D2.5-O
Elevation
9100
Aspect
SW
Latitude
45.32690
Longitude
-111.38400
Notes

On February 14, 2021, two splitboarders triggered an avalanche in Beehive Basin north of Big Sky. They were skinning up the slope when they triggered the avalanche. Both members of the party were caught, but Boarder 1 was able to grab trees and not be buried. Boarder 2 was carried approximately 300 feet downslope where he hit a tree and was critically injured. He was partially buried, entangled around a tree with his head downhill. Boarder 1 heard his partner’s screams, called 911 and went to his aid. He administered first aid and worked to keep him warm and calm. Gallatin County Sheriff Search and Rescue in Big Sky (GCSAR) left the trailhead within 45 minutes of the 911 call, skied to the scene and began providing care. A GCSAR helicopter arrived soon afterward and the injured boarder was short hauled to Big Sky Fire Department and medical care. Boarder 2 died from his injuries that night. The avalanche was 300 feet wide, 500 feet vertical and averaged 2 feet deep. It broke on a layer of facets and near the ground. Read the full accident report here: https://www.mtavalanche.com/accident/21/02/16

Number of slides
1
Number caught
2
Number buried
1
Number killed
1
Avalanche Type
Hard slab avalanche
Trigger
Snowboarder
Trigger Modifier
u-An unintentional release
R size
4
D size
2.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
24.0 inches
Vertical Fall
500ft
Slab Width
300.00ft
Weak Layer Grain type
Faceted Crystals
Weak Layer grain size
3.00mm
Weak Layer Hardness
F+
Slab Layer Grain Type
Precipitation Particles
Slab Layer Grain Size
0.50mm
Slab Layer Hardness
4F+
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

West pine creek

Date
Activity
Snowboarding

Toured into west pine today for a short outing. Got a handful of large and small whomps. Dug a snow pit on a south east aspect at 6800’ I got ectn however I had a log running through the side of my pit so I think that altered my results. I did take my shovel afterwards and did a pull test and the recent storm slab (30”) came off pretty easy.

Region
Northern Gallatin
Observer Name
Elton