24-25

Avalanche in Storm Castle Creek Basin

Date
Activity
Skiing

Somewhat fresh looking slab avalanche in upper Storm Castle Creek on an East facing slope. Looks like there might be a wet loose slide to the right of it as well. One small wet loose avalanche, probably from yesterday, in Maid of the Mist bowl. 

Region
Northern Gallatin
Location (from list)
Storm Castle

Stubborn Windslabs in Hyalite

Date
Activity
Skiing

Widespread wind effect in the alpine of Hyalite yesterday. The windslabs were fairly stubborn however, and were only breaking in very small pockets, not propagating outwards. Where the recent snow was still protected from sun and wind, large dry loose slides were easy to trigger.

Region
Northern Gallatin
Location (from list)
Hyalite - main fork
Observer Name
Wyatt Hubbard

GNFAC Avalanche Forecast for Sun Mar 9, 2025

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Today the primary avalanche problem is </span></span></span></span></span></span><span><span><span><strong><span><span>wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> where 5-7” of snow from Thursday was drifted into stiffer slabs. These drifts were reactive and easily triggered the last couple days. Yesterday in the northern Bridgers skiers triggered a few wind slabs that were 8-10” deep and 10-20’ wide. One person was caught and carried ten feet (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34550"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Two days ago Ian and I found similar fresh drifts that easily cracked under our skis (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/25/reactive-wind-slabs"><span><span>…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/25/reactive-wind-slabs-2"><span><spa…;, </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=Y8xb7L0c0Ug"><span><span><span><strong>…;

<p><span><span><span><span><span><span>Above freezing temperatures and sunny skies will make </span></span></span></span></span></span><span><span><span><strong><span><span>wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> a concern later in the day. These will probably be small, but could easily knock over a person. Watch and feel for a wet or moist snow surface to indicate you could trigger shallow loose snow slides, and anticipate this hazard to develop mostly around rock outcrops on slopes that receive direct sunshine.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Remain cautious of travel on steep wind-loaded slopes and steep sunny slopes today, especially above cliffs, rocks or thick trees where even a smaller slide would be more dangerous.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near West Yellowstone and the southern Madison and Gallatin ranges an additional concern is </span></span></span></span></span></span><span><span><span><strong><span><span>Persistent Slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> breaking 2-3’ deep on weak layers buried in late January. The last of these deeper avalanches were over a week ago (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/25/wind-loaded-slide-backside-lionhe…;). The likelihood has decreased, but the size would be big enough to have serious consequences. These slides were mostly on mid-elevation slopes with trees around and have surprised riders, leading to several close calls (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34421"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34413"><span><span><span><strong><span… Creek</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). </span></span></span></span></span></span><span><span><span><span><span><span>Travel one person at a time across steep slopes and have a partner watching from a safe spot. If you ride steeper slopes, choose terrain with minimal trees, rocks, cliffs or confined gullies.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Cooke City got less new snow last week, so the likelihood and size of potential avalanches is smaller. </span></span></span></span></span></span><span><span><span><strong><span><span>Wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> and </span></span></span></span></span></span><span><span><span><strong><span><span>wet loose avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> are a concern, but their size will be small and distribution is minimal. Avalanches breaking deeper on buried weak layers are unlikely. The last of these persistent slab avalanches were a couple weeks ago (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34382"><span><span><span><span><span><…;), and were the only slides of this type near Cooke City over the last couple months.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>While the snowpack is generally stable, you should follow standard safe protocols for travel in avalanche terrain. Expose only one person at a time to steep slopes and carry proper rescue gear (transceiver, probe and shovel). Stay alert for recent drifts and wet loose avalanches, especially in terrain where a small slide has higher consequences.&nbsp;</span></span></span></span></span></span><span><span><span><span><span><span>The avalanche danger is LOW near Cooke City.</span></span></span></span></span></span></p>

Upcoming Avalanche Education and Events

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Skier triggered Wind Slab Avalanches in Frazier Basin

Frazier Basin
Bridger Range
Code
SS-AS-R2-D1.5-S
Elevation
7500
Aspect
NE
Latitude
45.92780
Longitude
-110.96200
Notes

From obs: "Skier triggered wind slab on Northeast slope at 7,450 feet elevation. One skier was caught and carried roughly 10 feet before the slide came to a stop."

We also received reports from another group (IG story video) that triggered a couple similar sized wind slab avalanches in north facing chutes in Frazier Basin.

 

Number of slides
3
Number caught
1
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
R size
2
D size
1.5
Bed Surface
S - Avalanche released within new snow
Problem Type
Wind Slab
Slab Thickness
8.0 inches
Vertical Fall
100ft
Slab Width
20.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

small loose snow slides N. Bridgers

The Throne
Bridger Range
Code
L-N-R1-D1-S
Elevation
8500
Aspect
S
Latitude
45.88220
Longitude
-110.95200
Notes

The new snow was low density and sluffed easily on steep shady northerlies. On steep slopes facing the sun (south and east, and probably west) the new snow sat on a crust and became moist as the sun warmed it up and started to slide under skis. We saw a couple very small natural loose snow slides below rock outcrops on south facing slopes. Air temperatures were well below freezing, especially with wind chill, but the sun quickly warmed the recent new snow.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Loose-snow avalanche
Trigger
Natural trigger
R size
1
D size
1
Bed Surface
S - Avalanche released within new snow
Problem Type
Loose Dry
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Fresh reactive wind slabs N. Bridgers

The Throne
Bridger Range
Code
SS-ASc-R1-D1-S
Elevation
8300
Aspect
SE
Latitude
45.88220
Longitude
-110.95200
Notes

There was 6" of low density snow from yesterday. Winds were stronger than expected, from the north at the top of the Throne, and increased through the morning.

We found fresh drifts that were reactive, cracking easily and 5-10' wide out from our skis, on south and east facing slopes around 8000-8300'.

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
1
D size
1
Bed Surface
S - Avalanche released within new snow
Problem Type
Wind Slab
Slab Thickness
10.0 inches
Vertical Fall
100ft
Slab Width
10.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Shooting cracks in wind slab north of Cooke

Date
Activity
Skiing

From obs: "We found up to a 6” deep wind slab producing shooting cracks at Goose Lake on a NW facing slope at 10500ft."

Region
Cooke City
Location (from list)
Goose Lake
Observer Name
Noah Mattes