23-24

Mixed observations in Beehive Basin

Date
Activity
Skiing

ECTN x 5 and ECP x 1, down 45 (shallower spot as compared to the other 5). PST 30/100 SF, 60/100 end down 58. PST 40/100 end down 55. Two large whumpfs nearby. All obs were at 8700', W aspect (meadow between gem chute and next chute to the South). 

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

Midway meadows Republic Cr.

Date
Activity
Skiing

Republic creek tour snowpack observations: 

Observed collapsing/cracking in lower Midway meadows.  Snowpit tests produced unstable results - easy propagation and failure between old snow (Oct-Nov) and new snow (early December).  

Noted one old natural avalanche on south Woody Ridge, west aspect ~9500'.  

Significant surface hoar growth in Republic creek.  

Region
Cooke City
Location (from list)
COOKE CITY
Observer Name
BMG Level 1

GNFAC Avalanche Forecast for Sun Dec 17, 2023

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>A person can trigger a large, dangerous avalanche that breaks on weak snow in the lower half of the 1-3 foot deep snowpack. These avalanches can break wide, and can be triggered on slopes steeper than 30 degrees or from lower angle terrain that is connected to steep slopes.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>On Friday at Big Sky, ski patrol reported two avalanches thought to be naturally triggered during the day, and yesterday they confirmed at least one was triggered by a mountain goat. Based on the goat’s tracks, it was carried over 1000’ vertical and walked away from the debris apparently uninjured (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29552"><span><span><span><strong><span…; </span></span></strong></span></span></span><a href="https://www.mtavalanche.com/images/23/natural-avalanches-closed-terrain…;). Additionally, over the last three days we continued to receive reports of collapsing and whumphing of the snowpack, a clear sign avalanches can be triggered on steeper slopes. This red flag was experienced by skiers in the Bridger Range (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29561"><span><span><span><strong><span…;), Cooke City (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29555"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29539"><span><span><span><strong><span…;), Lionhead (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29563"><span><span><span><strong><span…;), and Beehive Basin (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29538"><span><span><span><strong><span…;).&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The poor snowpack structure is responsible for a long list of avalanches over the last week and a half (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/avalanche-activity"><span><span><span><stro… log</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>), both natural and human-triggered. On Friday Ian saw a couple recent natural avalanches at Lionhead which he discusses in a </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=OhmeSvFN4hI"><span><span><span><strong>…; (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29546"><span><span><span><strong><span…;). On Tuesday a skier triggered a large avalanche on Mt. Blackmore in Hyalite, and he generously shared a video from his POV (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=ff4qS1aF9Fs"><span><span><span><strong>…;). These videos are good examples of the type of avalanche you could trigger today.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The snowpack is slowly becoming more stable since the last storm, but recent avalanches and collapsing of the snowpack are warnings that dangerous human-triggered avalanches are possible. Choose terrain carefully. Consider the consequences of an avalanche if you travel on or below slopes steeper than 30 degrees, and thoughtfully evaluate the snowpack for the potential of an avalanche. Clear signs that you should stay off steep slopes include cracking, collapsing, recent avalanches, or poor stability test scores.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Heightened avalanche conditions exist, human-triggered avalanches are possible, and the avalanche danger is rated MODERATE.</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.

Observations North of Cooke City

Date
Activity
Skiing

From email: "Miller Ridge snowpit from today:  9300', NE Aspect.  HS: 67cms.  ECTP 11 at 36.  

Then we toured over for some runs on SW Henderson.  Obviously more supportable over there.  Less collapsing.

Aside from the widespread SH that has been forming on all aspects and elevations this week, the shady aspects appear to be getting more faceted mid-snowpack, while the solar aspects appear to be gaining strength"

Region
Cooke City
Location (from list)
Miller Ridge
Observer Name
Beau Fredlund

Collapsing in Bradley Meadow

Bradley Meadow
Bridger Range
Code
Latitude
45.83390
Longitude
-110.92700
Notes

Skiers in Bradley Meadow felt a large collapse while touring.

From obs: "Experienced a large collapse below the N half of Bradley Meadows in a small meadow - 7400 ft east aspect."

Number of slides
0
Number caught
0
Number buried
0
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year

Tour N of Bridger Bowl

Date

Height of Snow from 50-65. Traveled around Bradley Meadow area and down into Wolverine Basin. ECTP 19 @35 cm down (unstable result) 7500 ft east aspect. Experienced a large collapse below the N half of Bradley Meadows in a small meadow - 7400 ft east aspect.

Region
Bridger Range
Location (from list)
Bradley Meadow
Observer Name
MSU Avalanche Instructors

Instability in the Lionhead Range

Date
Activity
Skiing

Widespread wumfing between 7,000 - 8,700ft. in Targhee Creek. (12/15)

No natural slides observed.

Crazy large surface hoar also observed on open, southerly clearings, measured 1+ cm. Very rotten snowpack otherwise.

Region
Lionhead Range
Location (from list)
LIONHEAD AREA
Observer Name
E. Webb