Northern Gallatin

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

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." 

From obs (2/4/22) on Divide Peak: "the wind was cooking for most of the day and each lap the skin track was covered in places. There was wind loading along the ridge the snow was pretty cohesive and wanted fracture and propagate but I was not surfing steep enough slopes for this to happen"

I toured up to the East shoulder of divide to surf the 30 deg east facing slope

the wind was cooking for most of the day and each lap the skin track was covered in places

There was wind loading along the ridge 

the snow was pretty cohesive and wanted fracture and propagate but I was not surfing steep enough slopes for this to happen

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 

I would not have trusted any slopes that were getting loaded today 

attached are the photos 

Dug on Blackmore today. Aspect: 100 degrees. Elevation 9600 feet. Winds were moderate. HS 105cm. Concerning layer was Interface between older January snow and recent snow approx 92cm from the ground. This layer was very visible within the pit. Multiple Extended column test were done. All with similar results ECTN9 on this layer. Seems like there just wasn’t enough load on this yet to be a problem in this very specific area. Areas that are more loaded with this layer present are probably a different story. Going forward with caution based on these obs.