23-24

GNFAC Avalanche Forecast for Sat Feb 10, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Don’t let today’s sunny skies lull you into complacency. The avalanche conditions remain remarkably dangerous and we have continued the avalanche warning through tomorrow morning. If you get on, or even near, steep slopes, you are very likely going to trigger an avalanche.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Yesterday, after investigating an avalanche that was triggered in Tepee Basin on Wednesday, breaking 3/4 of a mile wide and 3-4 ft deep (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30547"><span><span><span><strong><span… and video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>), we remotely triggered an avalanche from the flats that broke 30 ft away below us, 2-3 ft deep, ~250 ft wide, and ran full path to the valley bottom (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=Nyk_y6bKPW4"><span><span><span><strong>…;). Riders in Lionhead yesterday triggered one slide from 100 ft away and saw several others break naturally (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30588"><span><span><span><strong><span…;). Slides are breaking deeper and larger than they have all season and are being triggered from a long ways away.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Expect more of the same today. This season’s extraordinarily weak snowpack will take a long time before it starts to stabilize. Stay off of and out from under all slopes steeper than 30 degrees.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Human triggered avalanches are very likely and the avalanche danger is HIGH.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Human triggered avalanches remain likely. Today’s new snow builds on an incremental load that has been accumulating all week, now adding up to 1.5-2 ft of snowfall since last Saturday (with reports of more at higher elevations).</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The snowpack has stayed touchy. Yesterday, a splitboarder remotely triggered a small avalanche south of Cooke City from 100 ft away and noted several recent small natural avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30573"><span><span><span><strong><span…;). Riders on Buck Ridge yesterday got large collapses (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30569"><span><span><span><strong><span…;). There have been many natural and human triggered avalanches over the last week (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/weather/wx-avalanche-log"><span><span><span…. and avalanche log</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>Be skeptical of all steep slopes, but be even more wary of slopes where the recent snow has drifted into deeper, stiffer slabs. Avoiding all slopes steeper than 30 degrees is the best way to avoid triggering and being caught by a dangerous slide. Be cautious passing beneath these slopes as well since you can just as easily trigger a slide from below.</span></span></span></span></span></span></p>

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

Upcoming Avalanche Education and Events

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Four avalanches at Lionhead

Date
Activity
Snowmobiling

From facebook: "We saw 4 different avalanches today at the west end of lions head. One triggered close to us. We were at the bottom in a safe spot on a high spot. North 44.73482. West 111.36946. 100 feet wide 100 feet vertical. Broke to the ground. Afterwards we watched 4 more go from a 1/4 mile to 1/2 mile away from us as we were in a safe position on a high spot watching them go. I'm sure we triggered the first one from the bottom, but we were 100 feet from the slope toe."

Region
Lionhead Range
Location (from list)
Lionhead Ridge
Observer Name
John Traxler

New snow above Melt Freeze Crust MFC

Date
Activity
Snowmobiling

  Test snow profile. The snow was surprisingly deep at HS 180, most likely from wind loading.  Felt and heard various collapses of the snow during the day while riding snowmobiles.  Approximately 30CM of fresh snow over a thin MFC followed by a dense thick snow slab.  CT and ECT indicate this MFC is the weakest layer.   CTM(16)SC down 30, ECTN(6) down 30

Region
Island Park
Observer Name
Ride Rasmussen Style - JA

New snow in wolverine bowl

Date
Activity
Snowboarding

Went for a quick tour into wolverine bowl today. Found new snow totals of around a foot in most places and a very thin melt freeze crust from high-pressure system on all shadier aspects while sunnier aspects had more of a noticeable crust beneath the new snow. Dug a 130 cm pit adjacent to the refrigerator chutes and got a CT15 Q1 @ 99cm and CT21 Q1 @ 30cm. Shallower result failed on facets beneath the recent melt freeze while the deeper result failed on the old melt freeze interface from earlier this season. Snow was coming down heavy by the time I left the bowl and wind was calm.

Region
Bridger Range
Location (from list)
Wolverine Bowl
Observer Name
A. Glenn

Remotely Triggered Avalanche, Tepee Basin

Tepee Basin
Southern Madison
Code
SS-AMr-R2-D2-O
Elevation
9200
Aspect
N
Latitude
44.90410
Longitude
-111.18500
Notes

While crossing flat terrain above a steep slope a rider triggered a large avalanche from 30' away. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
24.0 centimeters
Vertical Fall
350ft
Slab Width
300.00ft
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year