24-25

Mt. Henderson, localized collapsing

Date
Activity
Snowboarding

Localized collapsing and cracking yesterday on the upper slopes of Mt. Henderson, SW aspects.  HS ranged from about 30-75cms.  

Snowpit attached from a SW aspect about 9700', HS 50cms, ECTN9 @ 22cms (1-2mm facets above MF crust).

Region
Cooke City
Observer Name
B. Fredlund

Wet snow avalanches in Hyalite

Hyalite - East Fork
Northern Gallatin
Code
WL-N-R1-D1.5-U
Elevation
7900
Notes

From obs: "With the inversion and warmer temperatures yesterday, we (group of 3) discovered a super saturated, cohesive snowpack in Hyalite on the approach to High Fidelity. On the first pitch, I narrowly avoided a point release wet loose, probably around D1-1.5. After this we decided to bail. On the rappel, my partner narrowly avoided another wet loose, which he estimated to be D1.5 and deep enough to bury a person past their chest. The sun was not out but the mountains were shedding and there was evidence of warming and wind, because the trees had no snow on them. We were able to make ~2.5 feet in diameter “cinnamon rolls” by rolling a snowball downhill. If you’re going to any of the more exposed climbs in Hyalite, be very mindful of overhead hazards and wet loose problems which you would not expect this time of year." 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Wet loose-snow avalanche
Trigger
Natural trigger
R size
1
D size
1.5
Bed Surface
U - Unknown
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Wet Snow Instability in Hyalite

Date
Activity
Ice Climbing

With the inversion and warmer temperatures yesterday, we (group of 3) discovered a super saturated, cohesive snowpack in Hyalite on the approach to High Fidelity. On the first pitch, I narrowly avoided a point release wet loose, probably around D1-1.5. After this we decided to bail. On the rappel, my partner narrowly avoided another wet loose, which he estimated to be D1.5 and deep enough to bury a person past their chest. The sun was not out but the mountains were shedding and there was evidence of warming and wind, because the trees had no snow on them. We were able to make ~2.5 feet in diameter “cinnamon rolls” by rolling a snowball downhill. If you’re going to any of the more exposed climbs in Hyalite, be very mindful of overhead hazards and wet loose problems which you would not expect this time of year. 

Region
Northern Gallatin
Location (from list)
Hyalite - East Fork
Observer Name
Jackson Krause

Wet snow instability in Hyalite

Date
Activity
Ice Climbing

With the inversion and warmer temperatures yesterday, we (group of 3) discovered a super saturated, cohesive snowpack in Hyalite on the approach to High Fidelity. On the first pitch, I narrowly avoided a point release wet loose, probably around D1-1.5. After this we decided to bail. On the rappel, my partner narrowly avoided another wet loose, which he estimated to be D1.5 and deep enough to bury a person past their chest. The sun was not out but the mountains were shedding and there was evidence of warming and wind, because the trees had no snow on them. We were able to make ~2.5 feet in diameter “cinnamon rolls” by rolling a snowball downhill. If you’re going to any of the more exposed climbs in Hyalite, be very mindful of overhead hazards and wet loose problems which you would not expect this time of year. 

Region
Northern Gallatin
Location (from list)
Hyalite - East Fork
Observer Name
Jackson Krause

Lick Creek Obs

Date
Activity
Snowboarding

Toured up lick creek on Thursday morning. Mostly Cloudy, pretty warm around 37 degrees. Wind was gusting fairly hard at the ridge from the SW and had deposited and compacted lot of snow on the top of the NE Bowl. Dug a quick pit around around 8000' on the NE side of the ridge. Snowpack was about 60 cm deep and a quick compression test failed around CT 24 on near surface facets about 4 cm from the ground. The block that failed was a cohesive slab about 50 cm thick.

Region
Northern Gallatin
Location (from list)
Lick Creek
Observer Name
Alex A

GNFAC Avalanche Forecast for Fri Nov 22, 2024

Snowpack and Avalanche Discussion

<p><span><span><span><strong><span><span>Wind slab avalanches</span></span></strong></span></span></span><span><span><span><span><span><span> are the primary concern through the weekend. They could break under the snow that fell yesterday or in the new snow that is going to fall and be blown around tomorrow and Sunday. Either way, they could easily have enough power to knock you off your feet and into the plethora of rocks and stumps that are still exposed with a thin, early season snowpack. Avoidance is the key as getting caught in an avalanche of any</span></span></span></span></span></span><span><span><span><span><em><span> </span></em></span></span></span></span><span><span><span><span><span><span>size is likely to result in traumatic injuries. Skiers yesterday in the northern Bridger Range triggered several small slides that demonstrate how surprising quickly even a thin slab can get snow moving (</span></span></span></span></span></span><a href="https://www.youtube.com/shorts/cb81DKQ0G4M"><span><span><span><strong><…;). Wind drifts will be the largest and most dangerous in the areas with the most new snow (likely the Island Park area).&nbsp;</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>From public observations and our own limited fieldwork so far, the snowpack structure is looking pretty good for early season. Lots can still change, but for now, we’re cautiously optimistic about the lack of dramatic weak layers near the ground (</span></span></span></span></span></span><a href="https://www.youtube.com/watch?v=YCqhiLWpnrE"><span><span><span><strong>…’s video from Beehive Basin</span></span></u></span></strong></span></span></span></a><span><span><span><span><span><span>).</span></span></span></span></span></span></p>

<p><span><span><span><span><span><span>With each snowfall, there are more slopes that have continuous snow cover and are more appealing to ski or ride. Unfortunately, these are exactly where you need to be most wary about avalanches. It is a cliche for a reason - if there is enough snow to ride, there is enough snow to slide. Tilt the odds in your favor watching for signs of instability (recent avalanches, crack, or collapsing), carrying rescue gear (beacon, shovel, and probe) and following safe travel protocols in and around avalanche terrain. If you’re not ready to shift into winter-mode and follow these safe travel practices, plan to avoid steep snow-covered slopes with more than a foot of snow.&nbsp;</span></span></span></span></span></span></p>

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Thin windslabs in northern Bridgers

Frazier Basin
Bridger Range
Code
SS-AS-R1-D1
Latitude
45.92330
Longitude
-110.98000
Notes

Skiers triggered several very thin avalanches in the northern Bridger Range on 11/21/24. They broke only a couple inches deep on windloaded slopes, mostly in north facing couloirs. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
R size
1
D size
1
Slab Thickness
2.0 inches
Slab Width
20.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year