Photos

From Obs: "Today I watched as a sledder dropped a cornice causing the cornice to fall triggering an avalanche chasing him down the hill. The snowpack consisted of a wind slab on top of near-surface facets and a couple buried layers of surface hoar." Photo: B Rasmussen

Skiers observed several slab avalanches on the east face of Woody Ridge. They broke about 12" deep on a weak layer buried by recent snow. Photo: B Zavora

Skiers observed several slab avalanches on the east face of Woody Ridge. They broke about 12" deep on a weak layer buried by recent snow. Photo: B Zavora

The avalanche was triggered by a snowmobiler on a small, but steep slope that carried him into the trees in picture. The avalanche was shallow and wide. The rider was partially buried but did not survive. Photo: GNFAC

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

Small natural slides on 2/6/22 near Cooke City. @coldfear

From obs 2/6/22: "Small natural soft slab avalanche on a SE aspect at 8737'... Crown was 20cm deep and  approximately 15m wide... Around 10am"

We saw this natural avalanche on Feb 6, 2022 on the north side of Miller Mtn. near Cooke City. It appears to have broke near the end of the 10-14" snow storm that fell the prior day (2/5). Photo: GNFAC

On Feb 6, 2022 we rode north of Cooke City and found 10-14" of new snow and a layer of buried weak facets that created unstable conditions. This setup makes avalanches possible to trigger on steep slopes. In this pit we had an ECTP13 break on weak facets a couple inches below the new snow. Photo: GNFAC

From obs 2/5/22: "We were planning on skiing ainger basin area. Snow seemed safe while we were skinning, but we dug 3 pits because the wind was so strong. got semi-unstable results each time, ect 12 to 18 with clean propagation around 4 to 9 inches down, depending on the slope."

From obs (2/5/22): "Attempted to ski the SE Couloir on Emigrant Peak today. As we approached, we noticed recent avalanche debris in the runout zone of the line. We approached carefully and it looked to be somewhat recent in the last few days. Not buried by much recent snow but also did not look fresh as of that day. I am guessing it was triggered by a collapsed cornice but with poor visibility it was challenging to see any sort of crown or broken cornice above us. We did not ski the couloir. I dug a pit in the open east facing bowl below at 9200 ft. The snowpack was between 55-75cm deep. In this location, the bottom 30cm of the snowpack were very large, well-developed facets with some depth hoar. I got ECTN 14 about 45cm up and ECTX on the facet/midpack interface (30cm up)." Photo: H. Darby

Debris pile from a recent avalanche on the SE Couloir of Emigrant Peak. The avalanche appears to have occurred within the last few days and was likely triggered by a cornice fall. Photo: H. Darby

Ski for scale next to debris from a recent avalanche on the SE Couloir of Emigrant Peak. The avalanche appears to have occurred within the last few days and was likely triggered by a cornice fall. Photo: H. Darby
 

From obs (2/4/22): "…the last 2 days was finding buried surface hoar in many locations, up to 10'000'..... And we also observed a fresh avalanche yesterday on the NW aspect of Meridian Peak.  I couldn't discern a crown, due to our vantage point and a low cloud, but the debris pile looked relatively deep, and 12-48 hours fresh. Also, we had one significant collapse today on a mid elevation east aspect.  A slope with just a touch of wind deposit. (first collapse I've had in months!) The snow that collapsed appeared to be about 30-40' wide.  And a hasty pit showed the layer of concern to be buried SH." Photo: B. Fredlund

From obs (2/4/22): "Touchy surface hoar layer buried under slabs on top of old surface facets in wind protected north and east facing aspects. The layer was observed between 8400 and 9400 feet in the southern Absaroka Range, in Yellowstone National Park. Intentionally skier triggered D1 and D2 slabs 10-30cm thick." Photo: S. Rathbun

From obs (2/4/22): "Touchy surface hoar layer buried under slabs on top of old surface facts in wind protected north and east facing aspects. The layer was observed between 8400 and 9400 feet in the southern Absaroka Range, in Yellowstone National Park. Intentionally skier triggered D1 and D2 slabs 10-30cm thick."

Photo: S. Rathbun

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"

This morning while ascending a line on Sawtooth Mountain (Lower Novocain) we triggered an avalanche (ASu-SS-R2-D2-O)  that caught and carried my partner an estimated 180M and partially buried him. His leg and hand were unburied and excavation of the head was done in less than 2 minutes of the incident. The avalanche only involved new snow from the last 48hrs and was triggered on a MF crust/facet combo 30cm down(formed 1/30/22). The avalanche was 30cm at its deepest and 20-30M wide and ran 250M. We were lucky to find both skis and poles a little ways downslope. No injuries were sustained.

We both agree that we were trying to outsmart the instability that was present on steeper S facing terrain and should have turned around much sooner, we were very lucky. There was 30+cm HST in favored areas and the high winds from 1/31/22 formed some sensitive windslabs in specific areas. 

Graph of Snow Water Equivalent (SWE) at SNOTEL sites in the GNFAC forecast area from October 1, 2021 to January 30, 2022. It highlights the extended dry conditions in January that contributed to weak layers forming at the top of the snowpack. GNFAC