23-24

GNFAC Avalanche Forecast for Tue Mar 19, 2024

Snowpack and Avalanche Discussion

<p>Wet snow avalanches will increase in size and volume as temperatures rise. These will most likely release as loose snow avalanches, but larger, wet slab avalanches are possible. Backcountry travelers or smaller wet snow slides may trigger large, dry snow avalanches breaking on deeply buried persistent weak layers. The danger of both will rise throughout the day as melt-freeze crusts break down and the surface snow becomes wet.</p>

<p><span>Temperatures barely dipped below freezing last night, and wet snow concerns are increasing.</span> The snow surface and avalanche conditions will evolve quickly and will vary significantly by aspect. At Beehive Basin yesterday, we noted these differences and that backcountry travelers must anticipate these daily changes to stay safe (<a href="https://youtu.be/Eb7HWFq7A0Q"><strong><span>video</span></strong></a&gt;). Local ski patrols mitigated the risk of wet snow avalanches with terrain closures. Look at the photos and read about a small avalanche on <strong><a href="https://www.mtavalanche.com/node/31515">Mt. Blackmore</a></strong>, a small, wet snow avalanche that triggered a dry snow avalanche on Woody Ridge (<a href="https://www.mtavalanche.com/node/31513"><strong><span>photo and details</span></strong></a>), and slides on Crown Butte and Scotch Bonnet that gained significant volume for examples of wet snow activity (<a href="https://www.mtavalanche.com/images/24/wet-loose-snow-avalanche-crown-bu… Butte wet snow avalanche</span></strong></a>,<a href="https://youtu.be/__KumkBkUJ4"><strong><span&gt; video</span></strong></a>). Think like the local ski patrols and “close” terrain by moving to cooler aspects or heading home before surface crusts break down and more than the top few inches of the snowpack get wet. Ensure a safe exit through lower elevations where temperatures are likely warmer.</p>

<p>Large, dry slab avalanches breaking deep and wide on persistent weak layers remain a scary possibility. The recent avalanche on Woody Ridge <a href="https://www.mtavalanche.com/node/31513"><strong><span>outlined above</span></strong></a>, a slide in the Taylor Fork that piled debris high in the runout zone (<a href="https://www.mtavalanche.com/node/31479"><strong><span>Taylor Fork photo and details</span></strong></a>) and an avalanche on the <a href="https://www.mtavalanche.com/node/31460"><strong><span>Lawnmower</span><…; just outside the advisory area demonstrate the potential. Select smaller slopes with fewer consequences and follow safe travel protocols if you choose to enter avalanche terrain (<a href="https://youtu.be/__KumkBkUJ4"><strong><span>Cooke City video</span></strong></a>). Like the rest of the advisory area, the snowpack structure is weak in the Bridger Range, but we are unaware of any recent deep slab avalanche activity. Thus, wet snow avalanches are the dominant concern in the Bridger Range.</p>

<p>The avalanche danger will start the day rated as MODERATE. The danger of wet snow avalanches will quickly increase to CONSIDERABLE, with slides becoming likely as the day warms.<span>&nbsp; </span></p>

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Wet loose snow avalanche Mt Blackmore

Mt Blackmore
Northern Gallatin
Code
WL-AS-R1-D1
Elevation
9750
Aspect
SE
Latitude
45.44440
Longitude
-111.00400
Notes

From IG:

Southeast aspect on Mt Blackmore. Unknown time and date. Elevation 9700 to 9800’

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Skier
R size
1
D size
1
Problem Type
Wet Snow
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Natural Wet Snow Avalanche Triggers Dry Slab Avalanche Woody R.

Woody Ridge
Cooke City
Code
SS-NL-R2-D2-O
Elevation
9500
Aspect
E
Latitude
44.99970
Longitude
-109.91600
Notes

From Obs: “We were skinning in the valley to the East of Woody Ridge near the North end and observed a wet slide occur naturally due to a point release, moving about 500 ft downslope. While that was occurring it remotely triggered a dry slab avalanche approx. 50-100 ft adjacent on the same slope and elevation. The crown appeared to be 3 ft deep, possibly thicker, but we were viewing from afar so hard to tell. 9500 ft elevation, East aspect. 12:02 PM March 17, 2024. Air temp approx. 30F clear skies all day.”

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Avalanche triggered by loose snow avalanche
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Slab
Slab Thickness
36.0 inches
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Wet loose snow avalanche Mt Blackmore

Date
Activity
Skiing

From IG:

Southeast aspect on Mt Blackmore. Unknown time and date. Elevation 9700 to 9800’

Region
Northern Gallatin
Location (from list)
Mt Blackmore
Observer Name
Cooper Daniels

Natural Wet &amp; Dry Avalanche Activity on Woody Ridge

Date
Activity
Skiing

We were skinning in the valley to the East of Woody Ridge near the North end and observed a wet slide occur naturally due to a point release, moving about 500 ft downslope. While that was occurring it remotely triggered a dry slab avalanche approx. 50-100 ft adjacent on the same slope and elevation. The crown appeared to be 3 ft deep, possibly thicker, but we were viewing from afar so hard to tell. 9500 ft elevation, East aspect. 12:02 PM March 17, 2024. Air temp approx. 30F clear skies all day. 

Region
Cooke City
Location (from list)
Woody Ridge
Observer Name
Nathan Iltis