23-24

Remotely Triggered Avalanche Below Hyalite Peak

Hyalite Peak
Northern Gallatin
Code
SS-ASr-R1-D2-O
Aspect
E
Latitude
45.38710
Longitude
-110.96100
Notes

An avalanche was triggered by skiers crossing a slope 400' below the crown. 

From obs: "My partner and I remotely triggered a persistent slide on an East facing slope at 9350ft. The slide ran off the Evil Twin ridge, just below the large main summer trail bowl of Hyalite Peak. My partner and I were spaced out ~50ft when we both felt and heard a large whumpf. We looked up and saw the avalanche slide, but were both out of harms way from the path. The starting zone was ~400ft above us and the slide ran ~500ft in total length. The crown was just over 2ft deep at its max and 150ft+ wide. The were signs of recent wind loading as we approached the bowl prior to the slide." 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
1
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
18.3 inches
Slab Width
150.00ft
Images
Crown of a Skier Triggered Slide on Hyalite Peak
Debris Hyalite Peak
Hyalite Peak Avalanche 2
Hyalite Peak Avalanche 1
Snow Observation Source
Remotely Triggered Avalanche Below Hyalite Peak
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
23-24

Skiers triggered an avalanche on an east-facing slope at 9350ft.

From obs: "The crown was just over 2ft deep at its max and 150ft+ wide. The were signs of recent wind loading as we approached the bowl prior to the slide. We did not observe any other avalanches while we were out." Photo: T. Hoefler

Avalanche Details: Remotely Triggered Avalanche Below Hyalite Peak
Northern Gallatin, 2024-01-21
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    • Poor Structure and Collapsing, Centennials

    Centennials - Montana
    Island Park
    Code
    Latitude
    44.56530
    Longitude
    -111.80300
    Notes

    From obs: "Spent a day digging out the Hut in the Centennial Saturday 1/20. Our hasty pit, 20 deg. SW aspect at 7,000’ about 1/2 way into the hut showed 75 cm snow depth and various sized facets to a depth of 45 cm from the ground overlain by new snow. The structure was poor, and weak but we did not observe propagation in an ECT. Snow surfaces were damp on all aspect that we touched below 8,000’, pin wheel rollers on many steep slopes could be seen near the creek. Plenty of collapsing and “whumfing” on the way in kept us wary. Snow depths below 7,000 feet were as shallow as I have seen in 10 years operating the hut."

    Number of slides
    0
    Number caught
    0
    Number buried
    0
    Attached Videos
    Heads Up, We Are Seeing Avalanches, Island Park - 19 Jan
    Snow Observation Source
    Poor Structure and Variable Depth/Conditions in Hellroaring
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Red Flag
    Advisory Year
    23-24

    Skier Triggered Avalanche on SE bowl of Flanders

    Flanders Creek
    Northern Gallatin
    Code
    SS-ASr-R1-D2
    Aspect
    SE
    Latitude
    45.44020
    Longitude
    -110.93100
    Notes

    Skiers in the SE bowl of Flanders triggered an avalanche from the bottom of the slope. 

    From Obs: "as he turned into the bowl, a remote triggered avalanche ripped out above him. He was fast to reach a safe position in the trees by the time the avalanche finished its ride. The photo shows the 3 ski tracks, and the most left one is what remote triggered above." 

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Soft slab avalanche
    Trigger
    Skier
    Trigger Modifier
    r-A remote avalanche released by the indicated trigger
    R size
    1
    D size
    2
    Problem Type
    Persistent Weak Layer
    Images
    Avalanche on SE Bowl of Flanders
    Snow Observation Source
    Avalanche on SE bowl of Flanders
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    23-24

    Whumpfing at Ramshorn

    Date
    Activity
    Skiing

    We experienced widespread whumpfing on all aspects between 7200'-10200'. Solid slabs were also widespread, ranging between 4''-12'', all of which were sitting on facets. We dug many handpits and the results were extremely reactive, often propagating while cutting the pit. We did not observe any natural slides. We remotely triggered a cornice and large slab, but it did not run due to the slope angle. I'm certain if we ventured into or near steep terrain, something would've run. Between 7200'-9000' we saw many wet loose on slopes > 30, and set off large roller balls on most slopes. Down low it was very warm and felt like an early spring snowpack. From 9000'-10200' it was much colder and wind slab/board was widespread on E & SE aspects. Every aspect we touched up high had shooting cracks and loud whumpfing.

    Region
    Southern Gallatin
    Location (from list)
    Ramshorn Peak
    Observer Name
    Danyon Halama

    Skiers in the SE bowl of Flanders triggered an avalanche from the bottom of the slope. This happened on 01/20.

    From Obs: "as he turned into the bowl, a remote triggered avalanche ripped out above him. He was fast to reach a safe position in the trees by the time the avalanche finished its ride. The photo shows the 3 ski tracks, and the most left one is what remote triggered above." Photo: Anonymous 

    Avalanche Details: Skier Triggered Avalanche on SE bowl of Flanders
    Northern Gallatin, 2024-01-21
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