22-23

This Beacon Checker was installed by the Hebgen District FS snow rangers at the trailhead to Denny Creek and Lionhead Ridge. It was made possible by the family of Bradie Becker in partnership with The Friends of GNFAC. Bradie was killed in an avalanche on Lionhead Ridge on February 6th, 2022. Photo: J. Norlander

Lionhead Range, 2022-12-23

Natural avalanches in new snow near Cooke

COOKE CITY
Cooke City
Code
SS-N-R2-D2-I
Elevation
9500
Aspect
NE
Latitude
45.02020
Longitude
-109.93800
Notes

photos attached of some recent natural avalanches observed north of Cooke City today.

They all appear to be on N through E aspects, and primarily NE.  

Elevations between 9,000'- 10,000'.

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
New Snow
Slab Thickness
24.0 inches
Vertical Fall
800ft
Slab Width
150.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Weak Snow and Small Avy

Date
Activity
Skiing

Snowpack at 8000 ft in pioneers is about 2 feet deep and mostly facets. About a foot of 3 mm large squares on the ground, a slightly more dense 4F- layer of crust and facets and another foot on top of that of soft NSF and new snow. Intentionally triggered a very small test slope, slab failed on the lower facet layer. See pics of quick pit and test slope results. Boot and ski penetration to the ground. Weak.

Region
Dillon Area
Location (from list)
West Pioneer Mountains
Observer Name
Alex Dunn

GNFAC Avalanche Forecast for Fri Dec 23, 2022

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Triggering avalanches 2-4 ft deep in the recent and wind drifted snow remains possible today. More than 20” of snow fell in Cooke City earlier in the week accompanied by strong winds. A number of natural avalanches broke during the storm (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27293"><span><span><span><strong><span…; </span></span></strong></span></span></span><a href="https://www.mtavalanche.com/node/27300"><span><span><span><strong><span…;). The storm snow is slowly settling. Look out for shooting cracks as a sign that the new and drifted snow remains unstable. It’s been almost two weeks since the last slide broke on deeper weak layers, but even the slight possibility of such a slide should lead you to tone down your terrain ambitions a bit today (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27114"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/27148"><span><span><span><strong><span…;). The avalanche danger is MODERATE.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Avalanches breaking on weak layers low in the snowpack are the primary concern. Weak layers buried 3-4 ft deep are present on most slopes and in many places are capped by a cohesive slab. There hasn’t been recent activity on these layers, but our stability tests are showing they still hold the potential to slide (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=RNMts6wt0JQ"><span><span><span><strong>… Lake video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). Dig and test these layers. If there is any doubt - stay out of avalanche terrain.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Wind drifts of recent snow could also break in somewhat shallower avalanches (but still plenty deep to be a serious concern). Avoid wind drifts entirely or check to make sure they’re well bonded before committing to steep terrain. Triggering avalanches remain possible and the avalanche danger is rated MODERATE.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Please share avalanche, snowpack or weather observations via our</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/add/snow_obs"><span><span><span><span>…; </span></span></span></span></span></span><span><span><span><strong><span><u><span><span>website</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, email (</span></span></span></span></span></span><span><span><span><strong><span><span>mtavalanche@gmail.com</span></span></strong></span></span></span><span><span><span><span><span><span>), phone (406-587-6984), or Instagram (#gnfacobs).&nbsp;</span></span></span></span></span></span><span><span><span><span><span><span>&nbsp;</span></span></span></span></span></span></p>

<p>In Island Park, avalanches breaking on weak layers low in the snowpack are the primary concern today. Dig and test these layers. If there is any doubt - stay out of avalanche terrain. Wind drifts of recent snow could also break in somewhat shallower avalanches (but still plenty deep to be a serious concern). Avoid wind drifts entirely or check to make sure they’re well bonded before committing to steep terrain.</p>

Upcoming Avalanche Education and Events

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Photos attached of some recent natural avalanches observed north of Cooke City today.

They all appear to be on N through E aspects, and primarily NE.  

Elevations between 9,000'- 10,000'.

Photo: B. Fredlund

Cooke City, 2022-12-23

Photos attached of some recent natural avalanches observed north of Cooke City today.

They all appear to be on N through E aspects, and primarily NE.  

Elevations between 9,000'- 10,000'.

Photo: B. Fredlund

Cooke City, 2022-12-23

Photos attached of some recent natural avalanches observed north of Cooke City today.

They all appear to be on N through E aspects, and primarily NE.  

Elevations between 9,000'- 10,000'.

Photo: B. Fredlund

Cooke City, 2022-12-23

Natural avalanches around Cooke City

Date

Photos attached of some recent natural avalanches observed north of Cooke City today.

They all appear to be on N through E aspects, and primarily NE.  

Elevations between 9,000'- 10,000'.

 

Region
Cooke City
Location (from list)
COOKE CITY
Observer Name
Beau Fredlund