23-24
Whumphing near Cooke
While skiing near Scotch Bonnet Mountain skiers felt many small collapses and one very large one.
Skiers in Republic Creek also observed cracking and collapsing while in Republic Creek.
Whumphing in Bridgers
Multiple parties of skiers felt "thunderous whumpfs" while crossing a meadow on the way to Texas Meadows.
Cracking, whumphing in Beehive
Multiple parties reported signs of instability in the form of either cracking or whumpfing or poor results in stability tests while skiing in Beehive Basin on 12/17.
From obs: "One pocket in a glade of one of our lines had a short shooting crack ahead of my skis as I set our skintrack. ~1ft. of snow propagated uphill onto my skis." E.Webb
"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). " D. Sandberg
Skiers on 12/17 saw cracking while touring in Beehive Basin. Photo: E. Webb
Forecast link: GNFAC Avalanche Forecast for Mon Dec 18, 2023GNFAC Avalanche Forecast for Tue Dec 19, 2023
Whumpfing and Poor Structure
Today we rode out north of Cooke City towards Lulu Pass. We dug on a northeast-facing slope at 9600' below Fisher Peak with a depth of ~3' (HS = 88 cm). We had ECTP 21, twice, and PST 67/100 END results on weak-faceted snow above a stout crust. It was easy to find surface hoar in most places on this slope. We then traveled to a southern-facing slope where while ascending widespread whumpfing and cracking were heard and seen. At 9600' a very large whumpf was felt. Here we dug another snowpit with a shallower depth of ~2.5' (HS = 74 cm). Results were an ECTP 11, twice, and a PST 20/100 END. These results were again on weak-faceted snow above the same stout crust.
Beehive Basin Instability
We skied two west-facing slopes and one east-facing slope between 8,500 - 9,200ft. on the shoulders of Beehive Basin Sunday morning. The ice crust interface in the lower-middle snowpack seems to sit between two layers of rather incohesive, sugary snow. We did not get results on several hand shears which is thought to be because of the lack of a slab above the ice crust in the snowpack.
One pocket in a glade of one of our lines had a short shooting crack ahead of my skis as I set our skintrack. ~1ft. of snow propagated uphill onto my skis. With further examination (pictures), it seems that the slab in this pocket, located in a small northwest-facing aspect was more cohesive than other slopes skied today.
We did not see any other signs of instability during our tour. One natural, likely old avalanche was observed closer to Beehive Peak, on the east-facing steep section of Beehive Basin's west shoulder.
Whumphing in Bridgers
I skied off the backside of Bradley's with the intention of touring up and skiing those north facing shots off of Texas toward the playground. Skinning across the flat meadow below the cliffs heading toward Texas I got several thundering whumphs. I usually feel pretty comfortable on a Moderate day skinning up that notch and giving the overhead hazard as much birth as possible. But, it felt like remote triggers were a real possibility and I was by myself, so I decided not to test my hypothesis that I could set a low exposure skin track and spun back to the top of Bradley's. I was thinking of that observation from a few years back where the solo tourer skinned up those cones to the skinners left and triggered a slide that tickled the traditional skin track. I didn't get any collapses on other slopes, just skinning across that flat meadow. Coverage was as thin as you would expect. There were some steep tracks down Wolverine and off the side of Ramp that didn't produce any action.
Poor test score in Bradley Meadow
Poor test score near Bradley Meadow on an E aspect, at around 7600', during a Friends course. Height of snow was 65-70 cm, results were a sensitive ECTP 3 on the old facets.