Northern Gallatin

Two skiers triggered an avalanche while ascending the Banana Couloir on Ross Peak on the morning of 12/5/22. The skiers were approximately 150 ft from the top of the couloir when the avalanche broke 20 ft above the upper skier. The slide broke in wind drifted snow 6 inches deep and approximately 30 ft wide, across most of the couloir. The lower skier was waiting in a "safe spot on the side" but was also caught by the slide. The slide ran ~600 vertical feet, pulling out a deeper pocket of snow (1.5-2 ft deep) midway down the path. Both skiers were fully submerged as they were carried, but ended up partially buried near the toe of the debris. One skier had snow packed into his mouth and underneath his eyelids. They returned to the trailhead under their own power. 

We skinned into the Divide Peak cirque to check out the conditions in Hyalite for the first time this season. On our tour we saw a couple of small R1-D1 slides that had broken within the new snow. At our first pit we saw HS at 124 cm with 10 cm of new snow. We had a ECTP 30 on facets 64 cm down from the surface. Next we dug on a SE aspect with a HS of 127 cm and 15 cm of new snow. We got an ECTN-3 within the new and old snow. More importantly, the wind was picking up throughout the day, and it was transporting snow. Our primary concern today was new snow, and in the next few days it will be wind drifted snow.

Observed active windloading on the eastern side of Lick Creek today.

12-18 inch slab broke easily when ski cut and a small but very reactive cornice was rapidly building.

There was 6" of new snow in Hyalite Canyon with increasing winds throughout the day. Our primary concern is avalanches within the new and wind-drifted snow. Photo: GNFAC

Snow pack of 108cm on a 25 NE facing slope at 9,625'

Observed CT11 Q2 at new/old interface, 93cm, as well as an ECTN13 Q2 on what we believe to be a buried layer of surface hoar at 26cm. Also had some warming of the surface.

With the poor pit performance we decided to not ascend to the ridge and ski the intermediate terrain in the cirque, then out the drainage.

I toured in Lick Creek yesterday and thought I'd share a few things we noticed. Hopefully they are helpful observations!

While the skin track was still relatively flat and cutting through sloping meadows, we noticed a small sun crust on a southern aspect. 

As we skinned through the front side skiing zone, we noticed evidence of wind affected snow. We found some strong layers that sounded hollow, sometimes underneath ~2 inches of snow. As we gained the ridgeline, the wind slab became more obvious. It cracked under my weight, but I didn't see any shooting cracks or distinct collapses.