23-24

Climb Above Dribbles Gully

Date

Well I had to go see what the snow was doing today. We climbed the Fallen (about 100m below Climb Above Dribbles). On ascent there were no signs of instability (no cracking, collapsing, naturals, good results in hand pits, etc). New snow had accumulated to around 1m in spots however! No activity in the old snow, which seemingly gained some strength in the warm weather midweek (hardness in FCs went from fist to 4F from mon-fri). 
 

During the day, snowfall rates hit S2 at times, and accumulation was around 5 cm, with moderate winds and moderate drifting. On descent this new snow was touchy, and we observed 2 natural avalanches, max depth 15 cm, on the small end of size 1, F hardness, running less than 30-50m exclusively in new snow. (SS-N-R1D1-N)

Structure remains poor overall.

Region
Northern Gallatin
Location (from list)
Hyalite - main fork

Whumpfing and poor test scores near Bridger

Date
Activity
Skiing

Skinned up Bridger Bowl (currently backcountry above the Quad) to Bradley's Meadow and the Ramp. As we neared the top of the Alpine lift we started getting collapses and whumpfs whenever leaving the established skin track. There were a few inches of old, weak, faceted snow near the top of the Alpine lift, this increased to approximately a foot of old snow at the bottom of the Ramp (7900 ft). This was covered by a foot of new snow (1.5" snow water equivalent measured). We dug at the base of the ramp on a NE aspect and got two ECTP11s on the facets. 

Every other group we spoke with also experience multiple collapses. This clearly showed the snowpack was unstable and made decision making easy. We stuck to slopes <30 degrees. 

Region
Bridger Range
Location (from list)
The Ramp
Observer Name
Ian Hoyer

GNFAC Avalanche Forecast for Fri Dec 8, 2023

Snowpack and Avalanche Discussion

<p><span><span><span><span><span><span>Human triggered avalanches are likely today across our advisory area. New and wind drifted snow sitting on top of weak snow that fell in October and early November make for an unstable combination. Conditions are much less dangerous where this new snow fell onto dirt.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>The snowpack situation is relatively simple, but that doesn’t diminish its danger. Any slope that was snow covered before last weekend has the recipe for an avalanche. Unfortunately, this includes essentially any slope that has enough snow to ski or ride. You’ll find more of these slopes with weak snow at higher elevations and in the southern part of our advisory area. Our recent field videos from</span></span></span></span></span></span><span><span><span><strong><span><span> </span></span></strong></span></span></span><a href="https://www.youtube.com/watch?v=k7Hgppi96Rk"><span><span><span><strong>… Park</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/tCIhNk8uJoM"><span><span><span><strong><span><u><span>… City</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>, and </span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=ChZK6ex_f7k"><span><span><span><strong>…; illustrate the setup. As Doug identified in his video yesterday from Hyalite you can even find these conditions in snowy gullies surrounded by bare ground (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=GRMhHCvR_e4"><span><span><span><strong>… video</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>). The deeper the new snow is, the touchier and more dangerous conditions will be. Drifts from yesterday’s high winds have piled new snow up even more deeply.</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>Clear signs of instability were noted across the advisory area yesterday as heavy snow fell. Dave and I felt collapses (whumpfs) in Island Park (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29394"><span><span><span><strong><span…;). Big Sky Ski Patrol reported large natural avalanches in closed terrain with a snowpack similar to the surrounding backcountry (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/images/23/natural-avalanche-headwaters"><sp…;) and a skier triggered an avalanche in a backcountry snowpack at Bridger Bowl (</span></span></span></span></span></span><a href="https://www.mtavalanche.com/node/29393"><span><span><span><strong><span…;). Expect to trigger similar slides today if you get onto steep slopes.&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>We have a long winter ahead of us, keep your early season excitement in check and make appropriately conservative decisions. Avoid traveling on or beneath slopes steeper than 30 degrees today. The avalanche danger is CONSIDERABLE in the mountains near Bozeman, Big Sky, West Yellowstone, Island Park, and Cooke City.</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.

Natural avalanche in closed terrain at Big Sky Ski Resort on 12/7/23. Photo: BSSP

"A large natural slide came down from 3rd Fork, stepped down in the Elbow and again in the cone, and ran almost to the runout of Obsidian. Naturals came out of most of the Headwaters, with both Firehole and Hellroaring stepping down into old snow in the cones."


Forecast link: GNFAC Avalanche Forecast for Fri Dec 8, 2023
Northern Madison, 2023-12-08
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