Snow Observations List

From FB message: I triggered this one Thursday night (2/2/23). Got lucky it didn't gain speed and sack on itself. Been in this zone 1000 times, never seen it slide, always gotta be on your game... NE aspect in Beaver Creek.

Our group toured up into Beehive Basin yesterday with the goal of skiing Peru and returning via Middle Basin. Our ascents and descents on the day showed signs of small pockets of wind slab instability (cracking and small pockets pulling loose), but nothing significant. On our final ascent up the backside of middle peak, there was a large shooting crack, maybe 30 feet in length, but we adapted our ascent route and were able to avoid further significant instabilities. Hand pits showed a thin 2" wind slab on our final ascent slope. Throughout the day we noticed a few old crown lines varying from 1 to 2' in depth and up to about 150' wide. These crown lines were on E, NE, NW and W aspects. The debris appeared to not be recent as it was covered with new snow and eroded, and some of the crown lines were filling in. 

A 2’ storm snow avalanche in the Chippewa Notch area was apparently triggered by a rider. It propagated significantly across complex terrain, and ran through plenty of terrain traps/trauma trees.

We looked at the snowpack at lower elevations in the northern Gallatin Range (SE aspect, 8,300' elev.) and found a layer of buried surface hoar below last week's snow that was reactive in stability tests (ECTP20, ECTP22). There was also weak, sugary snow through the bottom half of the snowpack that should be kept in mind, especially where the snowpack is relatively shallow. Triggered one small, isolated collapse on a west facing slope around 7,500' where the snowpack was mostly 1-2' deep weak facets, and we found one small pocket that had a drift over the weak snow. The buried surface hoar below last week's snow makes large avalanche possible to trigger for at least a few days.

Impressive avalanche cycle in the Bridgers to view as the skies clear.  Most slides seemed to have happened mid storm.  Here’s some photos of a large slide on the west side/behind north boundary.  Not sure the name.

Avalanche (possibly sled/human triggered) on an easy to northeast facing slope around 9300 feet.  There were lots of sled tracks on the slope, which is located just out of the wilderness at the far end of Buck Ridge.  Slide and sled tracks appeared to be from after the weekend storm and we're covered with light snow from the last couple days.  Noted lots of wind transported snow along buck ridge this afternoon.

Today we skied the northmost avalanche path on the east face of Blackmore; the farthest lookers right avi path before the trees. There were strong winds blowing from the southwest which created a very strong, 3-5in deep, wind crust. Certain aspects were heavily wind-loaded creating a very pocketed snowpack in some places. In the first 100 feet of my descent, I experienced three whumpfs; all of which came from different pockets of snow. Some areas appeared to be very well bonded, whereas others were far less so. We also observed multiple crowns across the eastern face, all of which appeared to have slid a few days ago. They ranged in width from 50-300ft and looked to be 1-3ft tall. The runout and debris were not visible. 

Dug at South facing snowpit at 9700' near the base of a wind-loaded slope, ECTX HS:280. Continued on less than 200' up the slope, the skier breaking trail triggered the avalanche. The third skier in the group of five was caught, carried, and buried to the waist. The crown was 1-2' deep, and 50 feet wide. Location: South of Fisher Mountain. Yesterday triggered a small windslab on a north-facing slope on miller ridge, no one was involved. 

We triggered this very small slide on a steep convex  rollover by mt abundance. South facing. Triggered from on top by snow bike. Was only 60’ wide and didn’t run far at all. About a foot deep.  Some impressive high mark tracks in the area. No other signs of instability today.

Just wanted to report that I found very thin snow on west aspects in Specimen Creek, with unstable test results today.

Had an ECTP 13 down about 20 cm on the new/old snow layer from last weekend. Couple whoomphs, and observed some stiff WS formation on ridge lines. HS of 90cm and absolute junk on the bottom.

Great skiing on non-avalanche terrain, however.
 

Big Sky Ski Patrol reported a skier triggered avalanche in "The Mullet" in the backcountry outside the ski resort boundaries. One skiers was reportedly caught and carried by the slide. The initial skier triggered slide also triggered another avalanche in the adjacent "Rattail" avalanche path. Details are second hand and specifics could not be confirmed due to low visibility.

We skinned up the ridge of the Throne, and we dug two quick pits on the lower half of the slope. On the E aspect at 7,800' we had a HS of 4 feet. We got an ECTP 24 and 30 on the facets at the ground. 30 feet away, we dug a pit with less than 3 feet of snow, and we got an ECTX in that pit. This showed how spatially variable this area is after the new snow and wind. We continued skinning up the ridge to the top of the Throne, and we dug another pit. Here, we found 190 cm of snow, and we had an ECTP 14, 1.5' below the surface within the new snow from the last week. We did not see other signs of instability while touring or riding today. 

Did a couple runs just to the north of bacon rind, had good runs. Dug a pit and did an ECT test at about 8300 ft on a SE aspect, snow pack was about 4 ft deep. I got an ECT-P10 with a Q2 shear quality. My column failed and propagated on a thin barely visible strip of surface hoar in between the new and old snow, there was about 12 inches of new snow. Also noticed ‘many thin (appeared to be 4-5 inches)slab crowns, on steeper terrain right off the rode near the pulloff West facing aspect, also tons of the same shallow looking crown on the spur road up to big sky on the steep south facing stuff above the road.
 

Skied near Bacon Rind Creek on 2/1/2023. Surprisingly little wind affect, still some snow on trees and a soft snow surface. Excellent low angle powder skiing in wind protected areas. Underlying snow structure very weak though. Weak layer likely from the December cold snap buried ~40-50cm from surface is super concerning, not to mention basal weak layers and new snow interface... New snow from the 1/27-1/28 storm has settled to a soft slab (F-4F) 35cm thick. Still lots of snow available for transport.

100 cms of snow in the meadow at the head of Moonshine.  So much snow took a long time to make it to the top.  I have not seen the summit area wind affected like it is for a long time.  Actually dug a pit and performed an ECT approximately 50 meters north of the of the burn on an east facing swallow angle slope.  Pit depth 135 cms.  There was a thin hard/ice layer at mid depth in the snow.  ECTN with initiations  at 2 locations in the upper half of the snow pack.  An encouraging sign is the strengthening of the facted snow at the ground.  Skiing in the trees was good, the snow is dense.

I went for a walk up the main fork of hyalite (hyalite lake trail) and noticed several small slides on the east facing walls of the canyon. When I made it to Hyalite lake, it was snowing and poor visibility so I could not see the back basin walls very well but noticed a small slab avalanche in the back of Divide basin 

As we rode into Lionhead we saw many slides that either ran naturally or from cornice falls. Most of the slides happened Fri or Sat. Winds are blowing strong at all aspects and elevations. Slopes are being loaded further and we triggered a small slide (video) from 50 feet away (aka remotely triggered). This is a serious sign of instability and we were careful to not get on or underneath avalanche terrain.

Went skiing up in in Flanders area and saw several avalanches with crowns ranging from 1-3ft deep and running a several hundred yards wide. Also experienced 2 whumpfs and some cracks on a wind loaded aspect near the ridge

Not sure if this will be useful information, but it was interesting to me. Yesterday (1/30) in the illumination of the low-angle evening sun, I could see at least 4 crowns in the Crazies with a pair of binoculars from downtown Livingston. Mostly W-SW facing slopes above treeline on the group of peaks surrounding and including Iddings Peak. I am used to seeing windscoured W aspects, and had never noticed such conspicuous slides from town. Crowns estimated 2-3 feet deep, and most slides looked to be a couple hundred feet wide beat I could tell. I’m sure todays wind will remodel and transport all remaining evidence to the E side of the range. 

We rode up to Henderson Bench and then rode up the Goose Lake drainage. We dug two pits today, and we found buried weak layers that failed and propagated in both pits. On Henderson Bench (NE aspect) there was 7’ of snow (HS 213 cm), and we got an ECTP28 on a layer of buried surface hoar 2.5’ below the surface. We also dug on a west aspect above Goose Creek. There was 6’ of snow (HS 190 cm). The 14” of new snow had a SWE of 1.7”. Here, we got an ECTP 14 on a layer of near surface facets and surface hoar 1.5’ below the surface. After two days of finding buried weak layers that failed and propagated on different aspects, it’s apparent that triggering an avalanche on these buried weak layers is possible throughout the area.