23-24

Continuous Collapsing at Bacon Ridn

Date
Activity
Skiing

We got the same feedback that Dave and Doug did on 2/5/24 - collapsing every time we stepped out of the skin track or turned with any force, as well as a few sizable collapses triggered from inside the skin track. Very touchy, skied very well. Stayed well away from avy terrain.

Region
Southern Madison
Location (from list)
Bacon Rind
Observer Name
Mike Zenker

Multiple recent avalanche Centennials

Centennials - Idaho
Island Park
Code
SS-N-R2-D2-O
Aspect
N
Latitude
44.54240
Longitude
-111.75200
Notes

From obs. 2/11: "No details, came upon them while riding and making observations of the terrain. One was North-Northeast, the other was North-Northwest facing. Across the drainage from each other. Also, notice three other small avalanches on a west facing slope, about two miles east of the first two. All five were on slopes well over 30. In the centennial mountains, close to the continental on the Idaho/Montana border."

Number of slides
5
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
New Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

From obs: "No details, came upon them while riding and making observations of the terrain. One was North-Northeast, the other was North-Northwest facing. Across the drainage from each other. Also, notice three other small avalanches on a west facing slope, about two miles east of the first two. All five were on slopes well over 30. In the centennial mountains, close to the continental on the Idaho/Montana border."

Island Park, 2024-02-12

From obs: "No details, came upon them while riding and making observations of the terrain. One was North-Northeast, the other was North-Northwest facing. Across the drainage from each other. Also, notice three other small avalanches on a west facing slope, about two miles east of the first two. All five were on slopes well over 30. In the centennial mountains, close to the continental on the Idaho/Montana border."

Island Park, 2024-02-12

Still Weak and We Turned Around

Date
Activity
Skiing

We rode into the Throne today in the Northern Bridgers. Our objective was to get to the top of the throne this time and to see what the warm-up in early February did. We felt that without signs of instability and good travel practices, this was an appropriate goal with wind-loaded terrain being off the table. At the bottom of the Throne, we discussed that if we saw signs of instability such as cracking and collapsing it was time to turn around. About halfway up on an east-facing slope at 8000' we dug a snowpit to test for instabilities. What we found is that the warm-up didn't change much, and found dry faceted snow below a stout crust that did form. Stability tests were reasonable with a score of ECTN 21 and we felt comfortable continuing to the ridgeline above. On the backside of the ridge, we were able to easily trigger small avalanches (1-2" deep) in the new snow. While walking on the ridge we felt a large collapse and saw shooting cracks behind, below, and above us. This made us both jump a bit and was an obvious sign that it was time to turn around. We pulled the plug once again and began skiing down, but not before kicking off a few more loose snow avalanches on the north side of the ridge. 

Here's what we took away from this. First, the snowpack is still very weak and it will take more than just a short warm-up to improve stability. Second, areas where new snow has drifted into thicker slabs are concerning, and triggering an avalanche is likely. Third, new snow is bonding poorly to the old snow surface and as snow continues this new snow will be sensitive to human triggers. 

Region
Bridger Range
Location (from list)
The Throne
Observer Name
Zach Peterson

Instability on slopes over 30deg on Buck Ridge

Date
Activity
Snowmobiling

Witnessed multiple natural avalanches on slopes that exceeded 30deg of incline.  When riding on test slopes with similar conditions we saw shooting cracks all around the sled.  We broke a couple slabs on hills around 25degs right at the crest of the hill but only the crest broke or showed signs of instability.

Region
Northern Madison
Location (from list)
Buck Ridge
Observer Name
Ross Keene

Two Avalanche’s within a few hundred yards

Date
Activity
Snowmobiling

No details, came upon them while riding and making observations of the terrain. One was North-Northeast, the other was North-Northwest facing. Across the drainage from each other. 
Also, notice three other small avalanches on a west facing slope, about two miles east of the first two. All five were on slopes well over 30. In the centennial mountains, close to the continental on the Idaho/Montana border. 

Region
Island Park
Location (from list)
Centennials - Idaho

GNFAC Avalanche Forecast for Mon Feb 12, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>A person can trigger avalanches that break 1-4 feet deep and hundreds of feet wide, and avalanches can be triggered from flatter terrain below or connected to steep slopes. Last week the mountains near West Yellowstone and Island Park had an avalanche warning for seven days, and there were many natural and human-triggered large avalanches. Yesterday Doug skied near Hebgen Lake, and he had loud collapses in the skin track and saw large recent avalanches (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=V6p5P9Avcv8&amp;list=PLXu5151nmAvSH326z…;). Over the past week we have been overwhelmed with reports of natural avalanches, avalanches triggered from flat terrain, and large collapses of the snowpack. Before you go in the backcountry, our </span></span></span></span></span></span><a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><span><span><span… and Weather log</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span> is required reading to see the evidence of current dangerous conditions.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Near Big Sky, Cooke City and south of Bozeman less snow fell over the last week compared to the other mountains, but a similarly weak snowpack exists and avalanches have been breaking naturally and triggered remotely from flat terrain. I was in Hyalite yesterday, and while we did not see obvious signs of instability we would not trust this season’s very weak snowpack to hold any slabs of new or wind-drifted snow, and we avoided slopes steeper than 30 degrees (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=j8CwNxm0Hmg&amp;list=PLXu5151nmAvSH326z…;). Near Big Sky, on Saturday riders on Buck Ridge triggered an avalanche from flat terrain (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30621"><span><span><span><strong><span…;), and yesterday in Beehive Basin skiers remotely triggered two avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30670"><span><span><span><strong><span…;). Yesterday near Cooke City skiers and riders reported many recent natural avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30678"><span><span><span><strong><span…. Abundance photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30682"><span><span><span><strong><span…. Republic photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30673"><span><span><span><strong><span… Mtn. photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>).&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The evidence is clear that you could easily trigger a big avalanche. Plan to stay off of and out from under all slopes steeper than 30 degrees. Dangerous avalanche conditions exist and the avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>In the Bridger Range, moderate and strong winds over the weekend drifted recent snow into thicker slabs. These slabs avalanched naturally on Saddle Peak on Saturday afternoon (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30639"><span><span><span><strong><span…;), and yesterday Bridger ski patrol found 12-14” hard slabs near ridgelines. Today, similar slabs can be triggered by a person, and more snow and wind will grow fresh slabs that are easy to trigger.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>We have not seen avalanches break on old persistent weak layers in the Bridger Range since above freezing temperatures in late January, and there have been less signs of widespread instability. Although less likely, it is still possible to trigger an avalanche 1-2 feet deep on sugary, weak snow, especially with more new snow and wind on the way.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Avoid steep, wind-loaded slopes. On non-wind-loaded slopes carefully assess the snowpack for instability, and if you find a cohesive slab over sugary snow choose different terrain. Avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on non-wind-loaded slopes.</span></span></span></span></span></span></p>

King and Queen of The Ridge Results

We closed out King and Queen (of the Apron) with $23,208 raised! A huge Thank You to all who participated and raised funds for The Friends of the GNFAC!