23-24

GNFAC Avalanche Forecast for Wed Mar 6, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>An Avalanche Warning has been issued for the mountains around Cooke City, the Lionhead area near West Yellowstone, and Island Park, ID. Over a foot of snow has fallen in the last 24 hours and very dangerous avalanche conditions exist. Since Friday these mountains have received 3.6”-4.7” of </span></span></span></span></span></span><a href="https://avalanche.org/avalanche-encyclopedia/snowpack/snowpack-observat… water equivalent</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>. </span></span></span></span></span></span><span><span><span><span><em><span>This is a lot of weight! </span></em></span></span></span></span><span><span><span><span><span><span>It translates into 4-5 feet of snow. The snowpack is weak and strong wind has loaded slopes even further. Avoid all avalanche terrain including flatter areas underneath steeper ones. Don’t mess around. Slopes that previously avalanched are avalanching </span></span></span></span></span></span><span><span><span><span><em><span>again</span></em></span></span></span></span><span><span><span><span><span><span>. The danger is rated HIGH on all slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The Bridger, Madison and Gallatin Ranges had 2-3 feet of snow falling since Friday (1.7-2.8” of </span></span></span></span></span></span><a href="https://avalanche.org/avalanche-encyclopedia/snowpack/snowpack-observat…;). With this snow and strong wind came avalanches: a jaw dropping large avalanche in Hyalite on Arden Peak (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31175"><span><span><span><strong><span…; </span></span></strong></span></span></span><span><span><span><span><span><span>and </span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/24/arden-peak-slide"><span><span><sp…;), avalanches running a second time on Buck Ridge (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31217"><span><span><span><strong><span…;), and Dave getting surprised in Bacon Rind where he found 3-4’ deep avalanches in small, low-angled openings (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/31226"><span><span><span><strong><span…; </span></span></strong></span></span></span><span><span><span><span><span><span>and </span></span></span></span></span></span><a href="https://youtu.be/ZFbDhwpmdzA"><span><span><span><strong><span><u><span>…;). As a forecaster he was stoked, because seeing unusual avalanches is cool, but as a skier he was less stoked since it showed how bad things are. He found an equally unstable snowpack in Taylor Fork yesterday (</span></span></span></span></span></span><a href="https://youtu.be/BWLm-bYLkDE"><span><span><span><strong><span><u><span>…;). And let’s not forget that the Bridger Range had an Avalanche Warning on Sunday from a 24” storm (</span></span></span></span></span></span><a href="https://youtube.com/shorts/5bOHsGISbjQ?feature=share"><span><span><span…’s field video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>).</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Conditions are dangerous. Triggering avalanches is a real consequence of getting into avalanche terrain. A person needs to be extra careful traveling under steep slopes because triggering avalanches from the flats is possible.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Be patient. The snowfall just stopped and the snowpack needs a breather to adjust all the added weight.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The avalanche danger is rated CONSIDERABLE on all slopes.</span></span></span></span></span></span></p>

Upcoming Avalanche Education and Events

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

Sheep Mountain Avalanche

Sheep Mountain
Cooke City
Code
N
Elevation
9700
Aspect
SE
Latitude
45.07220
Longitude
-109.92800
Notes

While riding north of Cooke City today we observed a large debris pile southern end of Sheep Mountain. SE facing at ~9700'. With poor visibility, I couldn't see a crown but much of the path had been filled in by wind and the debris was covered with fresh snow, making it at least a few days old. This slope was remotely triggered earlier this year in January by riders from the bottom of the slope. 

Number of slides
1
Number caught
0
Number buried
0
Trigger
Natural trigger
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Sheep Mountain avalanche from few days ago

Date
Activity
Snowmobiling

While riding north of Cooke City today we observed a large debris pile southern end of Sheep Mountain. SE facing at ~9700'. With poor visibility, I couldn't see a crown but much of the path had been filled in by wind and the debris was covered with fresh snow, making it at least a few days old. This slope was remotely triggered earlier this year in January by riders from the bottom of the slope. 

Region
Cooke City
Location (from list)
Sheep Mountain
Observer Name
Zach Peterson

Remote Trigger Beaverhead Range

West Big Hole- Beaverhead Range
Dillon Area
Code
ASr-R2-D2
Elevation
7600
Aspect Range
N-NW
Latitude
45.33720
Longitude
-113.68900
Notes

From a phone call with a friend: "Pretty sure we remote triggered this slide while skiing down a low angle ridge next to it. We saw it while we were ascending the uptrack and it wasnt there on our first lap."

2 Pics are from highway and are from the next day.

N-NW Facing slope at 7600ft. approx 100 cm deep. some stepped down to ground. approx 250 feet across and ran 3-400ft vertical. Large dangerous avalanche.

Number of slides
1
Number caught
0
Number buried
0
Trigger
Skier
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
2
D size
2
Problem Type
Persistent Weak Layer
Slab Thickness
100.0 centimeters
Vertical Fall
400ft
Slab Width
250.00ft
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Photo from 03/03/2024: Skiers remotely triggered this avalanche while skiing down the low-angle ridge next to the slope on 03/02/2024. N-NW Facing slope at 7600ft. approx 100 cm deep. some stepped down to ground. approx 250 feet across and ran 3-400ft vertical. Photo: A. Dunn

 

Dillon Area, 2024-03-05

Photo from 03/03/2024: Skiers remotely triggered this avalanche while skiing down the low-angle ridge next to the slope on 03/02/2024. N-NW Facing slope at 7600ft. approx 100 cm deep. some stepped down to ground. approx 250 feet across and ran 3-400ft vertical. Photo: A. Dunn

Dillon Area, 2024-03-05

A Simple Equation in the Taylor Fork

Date
Activity
Snowmobiling

We rode into the Taylor Fork past Consolation Hill and to the weather station at Sunlight Basin. Winds were strong through the morning and we rode in a ground blizzard in all the open meadows along the trail in. There was not much for obvious drifting on the road, but the snow was obviously going somewhere. Snowfall intensity varied from a trace to an inch per hour (S -1 to S2). The highest precipitation intensities occurred around 1-1:30 PM as we began our ride out. 

We did limp our way to the Sunlight Basin pit site in poor visibility and dug, but the wind, snow and light were such that we couldn't even visualize the bowl near the weather station. Digging a pit, we found more of the same structure that we have tracked for a few months now. The depth hoar does not seem to have gained any measurable strength, but the layers of surface hoar are somewhat more decomposed. We got an ECTP 23 on a layer of facet in the mid-snowpack and an ECTP27 on the depth hoar

As we discussed in our video for the day, today and tomorrow the equation is simple... new and wind-drifted snow on a weak snowpack equals dangerous conditions. As we move into a period of high pressure for the rest of the week, the likelihood of triggering an avalanche will decrease as will signs of instability and, most likely, the frequency of avalanches. However, the consequences of getting caught will remain unchanged. As folks are enticed by steeper terrain later in the week, we strongly recommend an incremental approach to expanding terrain selection and avoiding slopes with terrain traps. Additionally, safe travel practices become essential if you are stepping into the ring, especially carrying rescue equipment, knowing how to use it, and traveling one at a time on any slope steeper than 30 degrees. 

Region
Southern Madison
Location (from list)
Taylor Fork
Observer Name
David Zinn

Another Remote Trigger

West Big Hole- Beaverhead Range
Dillon Area
Code
SS-ARr-R3-D2-O
Elevation
7600
Aspect
NW
Latitude
45.63320
Longitude
-113.81900
Notes

From a phone call with a friend: "Pretty sure we remote triggered this slide while skiing down a low angle ridge next to it. We saw it while we were ascending the uptrack and it wasnt there on our first lap."

2 Pics are from highway and are from the next day.

N-NW Facing slope at 7600ft. approx 100 cm deep. some stepped down to ground. approx 250 feet across and ran 3-400ft vertical. Large dangerous avalanche.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowboarder
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Slab
Slab Thickness
100.0 centimeters
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year