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.
24-25
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 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 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
Wind Slab Avalanche in Frazier Basin
Date
Activity
Skiing
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.
Region
Bridger Range
Location (from list)
Frazier Basin
Observer Name
R. Bechtold
We also witnessed a falling cornice today that washed some snow through rocks. Be aware of what's above you.
South of Cooke City
Date
Activity
Skiing
Expected to find a different snowpack in the area southwest of Cooke/Silvergate, but once again we found deep (HS 235cm), strong, stable snow.
Digging more than a foot or two into the snowpack is a chore. Even the north-facing snow below 8000' is incredibly dense and supportive.
It seems like recent warm weather really helped consolidate the snowpack.
Don't take this good stability for granted - Even though the snowpack is generally stable, there is still trouble to be found in more consequential terrain. In one area, we did find some upside-down snow. It seemed stable, but in very steep terrain, even a small pocket releasing can cause trouble. We also witnessed a falling cornice today that washed some snow through rocks. Be aware of what's above you.
Region
Cooke City
Location (from list)
Abiathar Peak
Observer Name
Staples
Wind Loading in Ainger Lake Basin
Date
Activity
Snowboarding
Toured into Ainger Lake Basin in the Northern Bridgers today. From the Shafthouse Trailhead we could see debris from past wet snow avalanches coming from Ainger Peak and Hard Scrabble Peak area. The slide in Ainger Lake Basin must have been at least a few days old as the slide path and debris were covered in new snow from the last snowfall. The evidence of multiple slides we saw in Ainger Basin looked like they came from rocks shedding snow in the warm weather we've been having. Our objective was the middle couloir on Ainger Headwall. It was very windy in the basin. The slope above Ainger Lake Basin that we had to cross to get to the couloir was heavily wind loaded. We toured up and the snow felt stable so I decided to slowly skin out to see how the snow on this slope felt. It quickly became hollow sounding and we turned around and got a couple laps in for the day from there. Up high in the basin sun baked slopes that froze over night were very slick and hard with a couple inches of new snow on top making skinning difficult in places as well.
Region
Bridger Range
Location (from list)
Frazier Basin
Observer Name
Connor Culver
GNFAC Avalanche Forecast for Sat Mar 8, 2025
Snowpack and Avalanche Discussion
<p><span><span><span><strong><span><span>Wind Slab avalanches </span></span></strong></span></span></span><span><span><span><span><span><span>breaking in drifts built from this week’s new snow are the </span></span></span></span></span></span><span><span><span><strong><span><span>primary avalanche concern</span></span></strong></span></span></span><span><span><span><span><span><span> today. These drifts are up to 2 ft deep and were easily triggered yesterday (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=Y8xb7L0c0Ug"><span><span><span><strong>…;). Drifts may be a little more stubborn today, but I expect there are many slopes where they can still be triggered. Winds on Thursday were out of the east and then shifted westerly yesterday, so drifts may be found in unusual locations. The surface texture of the snow will give you a good idea of where the drifts are. Either avoid these drifts today, or carefully assess and make sure they’re well bonded before getting onto steep slopes.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Around West Yellowstone, Persistent Slab avalanches are an additional concern</span></span></strong></span></span></span><span><span><span><span><span><span>, breaking deeper on weak layers buried at the end of January. We haven’t seen a ton of activity on these layers lately, but we did get a report of a slide breaking deeper yesterday in the Lionhead area, so they’re clearly still possible (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/25/wind-loaded-slide-backside-lionhe…;). These slides have mostly been breaking on mid-elevation slopes with trees around and have been surprising riders, leading to several close calls (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34421"><span><span><span><span><span><…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34413"><span><span><span><span><span><… Creek</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>). Make sure you’re only exposing one person at a time to steep slopes and have a partner watching from a safe spot, in case you get unlucky and trigger a deeper slide.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Expect small</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>as the new snow warms up in the strong March sun. These slides could break at your feet or sled or come down naturally from above, particularly around rock outcrops. These slides probably won’t be big enough to bury you, but could knock you off your feet, so be alert in terrain where that would be a problem.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>The avalanche danger is MODERATE today.</span></span></span></span></span></span></p>
<p><span><span><span><strong><span><span>Winds Slab</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 also the primary concerns near Cooke City, but they will be small and isolated today. </span></span></span></span></span></span><span><span><span><strong><span><span>The snowpack is generally stable.</span></span></strong></span></span></span><span><span><span><span><span><span> There are weak layers in the snowpack, but it’s been almost two weeks since the last slide on them (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/34382"><span><span><span><span><span><…;). </span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Stay alert so you don’t get surprised. Watch for cracking as a sign that a wind drift is unstable and pay attention as the snow surface gets wet, especially in very steep terrain where a tiny slide would have big consequences.</span></span></span></span></span></span></p>
<p><span><span><span><span><span><span>Large avalanches are unlikely and the avalanche danger is LOW.</span></span></span></span></span></span></p>
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