23-24

Snow appears stable

Date
Activity
Snowmobiling

Centennial range blue and Wilson creeks. Did not see any signs of avys , or snow collapsing or whooping. Riders were on exposed slopes steeper than 30 degrees on all aspects high marking. It seems the centennial range has A more stable pack than other advisory areas. Although did not evaluate snow pack or dig pit, we stayed in low angle terrain 

Region
Island Park
Observer Name
Tony

GNFAC Avalanche Forecast for Mon Feb 19, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>It is no secret that it is dangerous in the backcountry. Sledders and skiers are regularly triggering avalanches from hundreds of feet away. Yesterday, near </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/19875"><span><span><span><span><span><… Mtn.</span></span></u></span></span></span></span></span></a><span><span><span><span><span><span>, Alex and I saw over a dozen recent avalanches and likely triggered a slope ourselves from 500’ away (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30851"><span><span><span><strong><span…;, </span></span></span></span></span></span><a href="https://youtube.com/shorts/FiXdQ2N7Da4?feature=share"><span><span><span…;). We did not see the slide release during the 5-minutes we took our eyes off the slope, so it may have been a natural slide, which is even worse. No matter, the snowpack is fragile </span></span></span></span></span></span><span><span><span><span><em><u><span><span>throughout our entire forecast area</span></span></u></em></span></span></span></span><span><span><span><span><span><span> and traveling in or underneath slopes steeper than 30 degrees is hair-raising.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Triggering avalanches and collapsing (whumpfing) of the snowpack is all the “data” we need to determine its danger. No stability tests are required. There have been many close calls since Friday. People are getting bolder, but not necessarily wiser. Our </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> is breathtaking in its list of activity. Recent “greatest hits” include:</span></span></span></span></span></span></p>

<ul>
<li><span><span><span><span><span><u><span><span>N. Gallatin Range</span></span></u></span></span></span></span></span><span><span><span><span><span><span>: (Fri) Snowmobilers in Portal Creek remotely triggered 4 avalanches from ~900 ft away (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30799"><span><span><span><strong><span…;),&nbsp;</span></span></span></span></span></span></li>
<li><span><span><span><span><span><u><span><span>N. Madison Range</span></span></u></span></span></span></span></span><span><span><span><span><span><span>: (Sat) Snowmobilers near Cedar Mtn. triggered two big avalanches (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30818"><span><span><span><strong><span… 1</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, </span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30819"><span><span><span><strong><span… 2</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>).</span></span></span></span></span></span></li>
<li><span><span><span><span><span><u><span><span>S. Madison Range</span></span></u></span></span></span></span></span><span><span><span><span><span><span>: (Sat) In Taylor Fork a rider triggered a slide, was caught, deployed their airbag, got partially buried, and was uninjured (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30839"><span><span><span><strong><span…;).</span></span></span></span></span></span></li>
<li><span><span><span><span><span><u><span><span>Lionhead</span></span></u></span></span></span></span></span><span><span><span><span><span><span>: (Fri) At Lionhead, Ian and Alex&nbsp; saw a slide that was triggered by riders 150 ft away (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/30792"><span><span><span><strong><span…;).&nbsp;</span></span></span></span></span></span></li>
<li><span><span><span><span><span><u><span><span>Cooke City</span></span></u></span></span></span></span></span><span><span><span><span><span><span>: (Fri) Dave investigated a snowmobiler triggered avalanche on Scotch Bonnet which broke 2-4 feet deep and hundreds of feet wide (</span></span></span></span></span></span><a href="https://youtube.com/shorts/PP7ASWPJnlQ?feature=share"><span><span><span…;
</ul>

<p><br />
<span><span><span><span><span><span>A nibble of new snow yesterday is not enough to raise the likelihood of triggering a slide, but it isn’t helping either. Playing in avalanche terrain is serious and dangerous and rated </span></span></span></span></span></span><span><span><span><strong><span><span>CONSIDERABLE </span></span></strong></span></span></span><span><span><span><span><span><span>around Bozeman, Big Sky, West Yellowstone, Island Park, and Cooke City.</span></span></span></span></span></span></p>

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2 Natural Slides at Skyline

Skyline Ridge
Southern Madison
Code
N-R1-D1-O
Latitude
44.92050
Longitude
-111.23000
Notes

From IG: 2 avalanches from either this morning or yesterday at the bottom of Skyline ridge 2’ at the crown

Number of slides
2
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
1
D size
1
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

2 Natural Slides at Skyline

Date
Activity
Snowmobiling

From IG: 2 avalanches from either this morning or yesterday at the bottom of Skyline ridge 2’ at the crown

Region
Southern Madison
Location (from list)
Skyline Ridge
Observer Name
Jordan Meyers

Natural Avalanches S. of Cooke City

COOKE CITY
Cooke City
Code
N
Aspect
E
Latitude
45.02020
Longitude
-109.93800
Notes

From email: "Noted several 1-2 day old dry loose in steep terrain above the cliffs to the lookers left of Hang Ten. Also A large avalanche. crown propogated through the cliffs and looked to be about 200' wide and 1 1/2-2 ft. deep. Debris was no longer visible so I suspect this ran sometime during or shortly after the storm. (02/15)." 

Number of slides
2
Number caught
0
Number buried
0
Trigger
Natural trigger
Problem Type
Persistent Weak Layer
Slab Thickness
18.0 inches
Slab Width
200.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Photos of a Recent Avalanches S. of Cooke City

Date
Activity
Skiing

From email: "Noted several 1-2 day old dry loose in steep terrain above the cliffs to the lookers left of Hang Ten. Also A large avalanche. crown propogated through the cliffs and looked to be about 200' wide and 1 1/2-2 ft. deep. Debris was no longer visible so I suspect this ran sometime during or shortly after the storm. (02/15)." 

Region
Cooke City
Location (from list)
COOKE CITY
Observer Name
Gloria Roe