24-25

Skier-triggered Avalanche in Super Couloir at BBowl

Date
Activity
Skiing

From IG Message: “Skier triggered Pocket in super couloir. Wasn't very unexpected, the skiers left side felt a little slabbier than the skiers right and tried to stay off it but got blinded by a sick face shot. Triggered going over a sharky rock spot, not very fast moving and easy to ski out of. Snow depth was 2-2.5 feet”

Region
Bridger Range
Location (from list)
Bridger Bowl

Skier-triggered avalanche in Super Couloir

Date
Activity
Skiing

From IG Message: “Hey guys - my partner broke off a small avalanche in super couloir today… broke full depth across half the couloir, 2-3’ deep/20’ wide and looked like it ran around 500’. No one was caught. He might message you with pictures too but here’s a video from the top”

Region
Bridger Range
Location (from list)
Bridger Bowl

Small natural avalanches below ridge South of saddle peak

Date
Activity
Skiing

Saw debris from several small natural avalanches below the ridge on an east aspect south of saddle peak while driving up to bridger. Most looked like point releases but there was one that might have been a small slab. Unsure because the light wasn't right to tell if there was a crown.

We stayed low but found a pretty uniform snowpack other than a couple of spots with sun crusts.

There was also tons of snow blowing over the ridge when we left around 3pm.

Region
Bridger Range
Location (from list)
Argentina Bowl

BBowl obs

Date

From email: "A little bbowl storm skiing for me yesterday afternoon/evening. Measured 20-25cm settled storm snow at base area and 35-40cm at mid and upper mountain. Very graupel-rich storm, with lots of rimed stellars too. Winds were blowing from the N across the lower mountain and up to the top of bridger, then I got into the calm "detachment zone" with light winds for the rest of the way. Lots of relatively soft wind slab formation going on, maximum encountered slab depth was 30-40cm. Localized cracking in these drifts, and some subtle, muffled collapsing.

I found a variable amount of "older" snow underneath the new snow, not from the Oct 17-18th storm, but from earlier this week. This was absent at the base but increased to a variable 5-20 cm on easterly aspects on mid/upper mountain."

Region
Bridger Range
Location (from list)
Bridger Bowl
Observer Name
Ben VandenBos

N aspect above Bradley’s

Date
Activity
Skiing

45.8305, -110.9307, 7840’, NW aspect, 23°

ECTN3 failing on 3cm layer of 2mm buried facets at the ground. HS 65cm. 

SE aspect hand pit has much more favorable conditions due to the lack of faceted old snow. Snow near the ground was still moist. 

Region
Bridger Range
Location (from list)
Bradley Meadow
Observer Name
Shep

Blowing snow and developing wind slabs at B Bowl

Date
Activity
Skiing

Toured up to the top of PK this morning to check out the fresh snow and see if we could eek out some early season turns. Cold temps to start the day with some light to moderate wind out of the NW and evidence that the wind was certainly blowing snow around during the storm over the past 24 hours or so. Did not see any significantly developed slabs in a multitude of hand pits at mid elevations, but noticed a relatively consistent 2-4 inch denser layer (from the wind) on top of the softer snow below. 

Region
Bridger Range
Location (from list)
Bridger Bowl
Observer Name
E. Heiman

GNFAC Avalanche Forecast for Wed Nov 6, 2024

Snowpack and Avalanche Discussion

<p>This week’s storm changed the avalanche picture. Backcountry travelers will find a layered snowpack capable of producing avalanches across the forecast area in most mid to upper-elevation terrain. Storm totals since Saturday in the mountains around Bozeman and Big Sky are 20-24” (1.3-1.8” of <a href="https://avalanche.org/avalanche-encyclopedia/#snow-water-equivalent-swe… water equivalent-SWE</span></a>), with 10-14” near West Yellowstone and Island Park (1.1-1.4” SWE) and 7” (0.7” SWE) in Cooke City. Visit our <a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><strong><span>wea… log</span></strong></a> for a daily breakdown. As Alex discussed in a short <a href="https://www.youtube.com/watch?v=Fv-xejsRWkg"><strong><span>video</span>…;, the snow on the ground is likely the foundation of this season’s snowpack.</p>

<p>Expect and prepare for avalanches within the new and wind-drifted snow. Slides will be likely at the tail end of this week’s storm, especially around Bozeman and Big Sky, where the most snow fell and winds gusted 40-60 mph. Without additional loading, stability will improve throughout the week. However, uncertainty is high this time of year as we learn the specifics of a new snowpack. Employ an information-gathering mindset and a healthy distrust for steep snow-covered slopes. Signs of instability, such as recent avalanche activity, shooting cracks and collapsing, are red flags and reasons to avoid avalanche terrain. Dig a quick snowpit to assess for instability when obvious signs are not present.</p>

<p>Early season avalanches on the Sphinx last weekend (<a href="https://www.mtavalanche.com/node/32052"><strong><span>photos and details</span></strong></a>), outside the advisory area on Emigrant Peak on Monday (<a href="https://www.mtavalanche.com/node/32047"><strong><span>photo and details</span></strong></a>), along with an observation of signs of instability on Mount Blackmore from Saturday (<a href="https://www.mtavalanche.com/node/32041"><strong><span>observation</span…;) are clear indicators that avalanche season is here. Whether hunting, skiing, riding, climbing or sledding, if you cross a steep slope where snow is deep enough to cover the grass and rocks, you may be able to trigger a slide. Carry rescue gear (beacon, shovel and probe) and follow safe travel procedures in and around avalanche terrain.</p>

<p>Public observations are incredibly valuable as we develop a picture of the season's snowpack. Please contribute to our community’s knowledge by <a href="https://www.mtavalanche.com/node/add/snow_obs"><strong><span>submitting your observations</span></strong></a>, and look through our <a href="https://www.mtavalanche.com/snow-observations-list"><strong><span>obser… page</span></strong></a> for additional information before your next backcountry adventure.</p>

Upcoming Avalanche Education and Events

Our education calendar is full of awareness lectures and field courses. Check it out: Events and Education Calendar

Wednesday, November 13, 4-8 p.m., Montana State University Snow and Avalanche Workshop. Open to the public.

Climber triggered wind slabs at the Sphinx

Sphinx Mountain
Southern Madison
Code
HS-AF-R2-D1-I
Elevation
9600
Aspect
NW
Latitude
45.15820
Longitude
-111.47700
Notes

Triggered a small wind slab:

-9600'

-N aspect on the NW ridge of Sphinx Mountain 

-Strong SW wind

-Noticed other small crowns, likely triggered from another party traversing the north-facing bowl at similar elevations

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Foot penetration
R size
2
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
10.0 inches
Slab Width
25.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year