Looking at a weak layer of facets that the avalanche propagated on. Photo: GNFAC
From Obs: "We skied into Blackmore late yesterday with chief concerns of the weak layer @ around 110cm and wind loaded new slopes. We dug two pits and found no failures in our column or ECTs. With the wind on the ridge we dug a hasty pit near the ridge to see how it was bonding. Again no results.
We decided to ski our lines taking care to avoid potential trigger zones and particularly loaded slopes. About half way down, I took a turn to the skier's left of a spine and the skier's right side had a small surface-level release. This would probably not have buried a skier, but likely would have taken them or a ride above the cliff band."
We skied into Blackmore late yesterday with chief concerns of the weak layer @ around 110cm and wind loaded new slopes. We dug two pits and found no failures in our column or ECTs. With the wind on the ridge we dug a hasty pit near the ridge to see how it was bonding. Again no results.
We decided to ski our lines taking care to avoid potential trigger zones and particularly loaded slopes. About half way down, I took a turn to the skier's left of a spine and the skier's right side had a small surface-level release. This would probably not have buried a skier, but likely would have taken them or a ride above the cliff band.
On Sunday, February 6, Gallatin Country Sheriff Search and Rescue and the GNFAC responded to a avalanche in Lionhead. A snowmobiler was killed on a small steep slope when a shallow avalanche carried him into a terrain trap of trees. Photo: GNFAC
Climbers on the big sleep on Saturday reported strong wind and blowing snow. They witnessed a wind slab that broke above the climb, and estimated that it was large enough to bury, injure, or kill a person.
From obs 2/5/22: "We hiked into Flanders to check out the Big Sleep ice climb. It was super windy with lots of blowing snow and the ice was thin so we decided not to climb it.
We witnessed a sizeable wind slab or sluff pour over the big sleep. It covered the whole climb for a second and probably would've slammed a climber off the route. Maybe 20 x 20 x 6 in slab but thats loose estimate."
I toured out to Alex Lowe Peak today, and thought I’d share my observations. The wind was blowing fairly hard today, but was not transporting a great deal of snow anymore. I did not observe any natural activity, collapsing, or cracking, but there are some things to keep an eye on. A pit on an east aspect at 9500’ was 145cm deep, and an ECT failed at 12 on the new/old interface 15-20cm down. It would not propagate, and after 30 hits I tipped over the meter or so of column without it coming apart. The surface it bonded to is variable, though, so I would hesitate to make generalizations off of a single pit.
Another observation worth noting is that standing in my snow pit, I sank pretty much to the ground in the weak, faceted, lower portion of the snowpack. I experienced this again stepping off my skis at 8200’ along south cottonwood creek, when I promptly sank to my thighs. I imagine some areas will react poorly to a substantial load, but that doesn’t seem to be in the forecast.
I toured up to Divide today
the wind was still cooking and loading the east facing slopes
i did 3x stability tests (quick pits using my snow saw) as I gained the ridge towards the peak
each pit receiving poor test scores, failed and propagated just below the new snow from this week
i stuck to the sheltered lower angle trees
I would not have trusted any wind loaded/loading slopes today
on the way to the “pillow factory” I kicked off a very small harmless slide (photo attached)
this slide was on the same aspect and slope angle as the very small slide I kicked off yesterday (report submitted) just in a slightly different location
From obs on Divide Peak (2/4/22): "On the way out a surfed over a steep roll over that fractured and slid. It appeared to have slid on the new snow interface."
