23-24

Republic Creek Avalanches

Republic Creek
Cooke City
Code
SS-N-D2
Elevation
9000
Aspect
E
Aspect Range
W, E, NE
Latitude
44.98550
Longitude
-109.94100
Notes

From email on 01/13: "Toured into Republic creek with our class. Noted two D2 soft slab avalanches. One on a west aspect and the other on an east aspect at about 9000'. I estimate the crown was 15-40cm deep and likely ran on the same layer as other recent avalanches in the area." 

From email on 01/13: "From Miller Ridge today, I had a brief look into Sheep Creek, and to the mountains south of Cooke City, and observed 7 fresh slab avalanches (that happened in the last 1-3 days).  Will send photos of them later if I can get better views.

Most of them were on NEerly aspects, and appeared to be on the new/old Jan. 5th interface.  Mid and upper elevations, most commonly in wind loaded terrain.  Some propagating a few hundred feet wide. "

From email on 01/14: "One crown on the Middle Siren, probably part of the last cycle."

 

 

Number of slides
9
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
D size
2
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Republic Creek Obs

Date
Activity
Skiing

From email: "Toured into Republic creek with our class. Noted two D2 soft slab avalanches. One on a west aspect and the other on an east aspect at about 9000'. I estimate the crown was 15-40cm deep and likely ran on the same layer as other recent avalanches in the area. 

ECTP4 down 25cm on SH in one pit where there was recent wind transport and a more cohesive slab. Other pits in sheltered areas produced ECTN's on the same layer. HS 100cm, 8200', W aspect. Some localized cracking and ,collapsing."

Region
Cooke City
Location (from list)
Republic Creek
Observer Name
Nina Hance

From obs: "Saw this avalanche today on the North end of Sheep from the Round Lake warming hut. Natural or possible snowmobile trigger" Reported yesterday, 01/12, likely a natural avalanche that happened near 01/10. Photo; J. Mundt

Cooke City, 2024-01-13

Large Whumpf

Date
Activity
Skiing

I observed a large whumpf in a flat meadow, around 8500'

Region
Northern Madison
Location (from list)
Beehive Basin
Observer Name
Anonymous

Avalanche on Sheep Mt

Date
Activity
Snowmobiling

Saw this avalanche today on the North end of Sheep from the Round Lake warming hut. Natural or possible snowmobile trigger 

Region
Cooke City
Location (from list)
Sheep Mountain
Observer Name
Jake Mundt

GNFAC Avalanche Forecast for Sat Jan 13, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Temperatures are dangerously frigid and the snowpack is unstable. This is a worrisome combination. Think long and hard before venturing out into the backcountry today. Any bad situation you get into can very quickly become much worse in such cold conditions.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Natural avalanches were reported over the last several days on The Fin, Henderson Mtn., Sheep Mtn., and Scotch Bonnet Mtn. near Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29906"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29921"><span><span><span><strong><span…;) and in closed terrain at the Yellowstone Club near Big Sky (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29873"><span><span><span><strong><span…;). There were two skier triggered slides yesterday. One slide broke a foot deep on Miller Mtn. near Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29915"><span><span><span><strong><span… and photos</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>) and another 2 ft deep on a wind-loaded slope in the Big Sky area (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29925"><span><span><span><strong><span…;). Slides are being triggered from a distance, raising concerns that you could trigger a slope from below (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=aTnE5gzG1sc"><span><span><span><strong>… Fork video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://youtu.be/QNkJeGFSPYs"><span><span><span><strong><span><u><span>… 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>The snowpack situation is simple - a very weak snowpack has been pushed to its breaking point by snow and wind over the last week and avalanches are being triggered, both naturally and by people. Human triggered avalanches are likely today. Avoid traveling on or beneath steep slopes. The avalanche danger is CONSIDERABLE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Thursday’s foot of new snow was low density and noncohesive, but the winds picked up last night and drifted it into stiffer slabs (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=GJxMtiIQGbs"><span><span><span><strong>… Range video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). This will make it easy to trigger avalanches on any wind loaded slope, breaking on the weak layers beneath the new snow. Watch and feel for signs of wind drifting and avoid those slopes. Dig and perform a stability test before riding any steep slope. Triggering avalanching is likely and the avalanche danger is CONSIDERABLE on wind-loaded slopes and MODERATE on all other slopes.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The northern Gallatin Range has received less new snow than elsewhere, reducing the likelihood of an avalanche, but the same sorts of slides as elsewhere are still possible, including facet sluffs gouging deep into the weak snowpack (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=Y0LROtnc7Us"><span><span><span><strong>… Ridge video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Carefully evaluate the snowpack before committing to steep slopes and be alert for signs of instability. The avalanche danger is MODERATE.</span></span></span></span></span></span></p>

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Skier triggered wind slab near Big Sky

NORTHERN MADISON RANGE
Northern Madison
Code
HS-ASu-R2-D2-O
Elevation
9700
Aspect
S
Latitude
45.29520
Longitude
-111.41000
Notes

On 1/12/24, a skier triggered a 2 ft deep avalanche on a wind loaded south facing slope at 9700 ft near Big Sky and was caught and carried by it.

Number of slides
1
Number caught
1
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
24.0 inches
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Skier triggered slide near Big Sky

Date
Activity
Skiing

On 1/12/24, a skier triggered a 2 ft deep avalanche on a wind loaded south facing slope at 9700 ft near Big Sky and was caught and carried by it.

Region
Southern Madison
Location (from list)
NORTHERN MADISON RANGE