Northern Gallatin

Strong winds and wind slab avalanche in Hyalite

Date
Activity
Ice Climbing

Climbed in the Mummy II area in Hyalite today. West facing ~7,500'. Lots of spindrift coming down onto the climbs in the area and we noticed lots of snow blowing around up high. No snow fell while we were there but our trail in was almost fully filled in and covered with a few inches to a couple feet of wind slab on the way out. Saw a small natural slide that started at the bottom of Cyptorchid. Crown was 10' wide and 8-18" deep, it ran 150' down a very shallow slope and covered the climbers trail. 

Region
Northern Gallatin
Location (from list)
Hyalite - main fork
Observer Name
Reid Beck

Wind slab triggered on east face of Mt Blackmore

Date
Activity
Skiing

Triggered a small wind slab avalanche on the east face of mt Blackmore today at 9850 ft elevation. Around 5 inches thick, ~ 20 ft wide, and ran for 100 ft. No skiers were caught but the slab was very reactive. We were assessing the snow as we climbed but skied a slightly more eastern aspect than we were planning and it was more reactive than expected. Strong winds gusting all day, no active transport observed but obvious that the wind slabs have not settled. 

Region
Northern Gallatin
Location (from list)
Mt Blackmore
Observer Name
Isabel Masi

Lower Hyalite

Date
Activity
Skiing

Explored slopes in lower Hyalite Canyon between 6000-7000 ft in elevation. Really close to being skiable and good. Otherwise, we found snow depths ranging from 6 inches to 2 feet. Generally very weak and faceted with thick crusts on slopes with a southerly tilt. All this weak snow probably won't be an issue because this area only gets the scraps from storms and never has enough loading to make an avalanche problem. 

Region
Northern Gallatin
Location (from list)
Hyalite - main fork
Observer Name
Staples & Darby

Surface Hoar on Big Ellis Ridge

Date
Activity
Skiing

Cold temps and sunny days starting to create some surface hoar forming seen on the primary ridge of big Ellis. Surface hoar was less widely distributed on the primary ski zone but was present all along the top of the ridge. 

Region
Northern Gallatin
Observer Name
Koby Gordon

Sub-par test scores in Big Creek

Date
Activity
Skiing

I toured Big Creek today in the southern Paradise Valley, taking Donahue Creek trail up off of Big Creek to ski the low angle meadows above. The west face of the first meadow was fairly wind loaded and approximately 80cm deep.
The snowpack appeared to be approximately 20cm of soft powder over 30cm of a wind slab, all sitting on top of another 30cm of fairly loose, course, facets. 
I conducted a compression test, and had a failure at 17 taps where the wind slab collapsed on the loose snow below. I did an extended column next, and recorded a score of ECT16P, with the failure propagating below the top layer of powder within the slab on the facets. 
Prior to filling in the pits, I jumped on my skis approximately 4 feet upslope of them, and the second jump caused the snowpack on the back of the pit to collapse when the slab slid. 

Region
Northern Gallatin
Location (from list)
NORTHERN GALLATIN RANGE
Observer Name
Jake Ahmann