Snow Observations List

From IG: “Here is a big avalanche remotely triggered yesterday up lionshead area”

From IG 2/10/24: “Multiple avalanches in the northern lions head on the eastern half of the compass. All were at around 8,500 feet.”

Toured up an east facing slope near the northwest arm of Hebgen Lake. We did not experience any collapsing or cracking on or off our ascent route but we did experience whumpfs on the ski down. At the top of the ridge at 9000 ft on either side of our skin track were three different avalanches. They all looked to be natural. One was pre recent storms, one was perhaps 24-48 hours old and maybe 500 feet wide, and one looked to be very recent, perhaps in the last 12 hours. We got a good look at the recent slide. It had no tracks in or out of it. It was at least 200 feet wide and broke 1-1.5 meters deep, gouging to the ground in spots and ran to the trees almost full path. Besides the avalanches, near the ridge line was a 30° planar slope that had a small concavity. There were shooting cracks everywhere, and it looked like the cracks propagated into a slab that would have broken up more if the slope had been steeper. It almost looked like a crevasse field with how many cracks there were. Photo is included but I don't think shows just how broken up that "relatively benign" terrain was. I have never seen anything like that before! 

From facebook: "We saw 4 different avalanches today at the west end of lions head. One triggered close to us. We were at the bottom in a safe spot on a high spot. North 44.73482. West 111.36946. 100 feet wide 100 feet vertical. Broke to the ground. Afterwards we watched 4 more go from a 1/4 mile to 1/2 mile away from us as we were in a safe position on a high spot watching them go. I'm sure we triggered the first one from the bottom, but we were 100 feet from the slope toe."

Rode along Lionhead Ridge from Denny Creek to Watkins Creek and around into the head of Targhee Creek. Saw dozens of avalanches that broke within the last week. Most of the slides looked to have broken early this week with a couple looking like they broke in the last 24 hours. Slides broke on all aspects, both above treeline and well below treeline, and on both wind-loaded and nonwind-loaded slopes. Some looked to be naturals and some looked to have been rider triggered. One of the slides in Watkins Creek broke across three avalanche paths/gully features and was one of the larger slides we've seen this season, looking to have piled up debris 10+ ft deep. All these slides looked to have broken on one of the December surface hoar layers at the top of the early season facets.

Dug a pit adjacent to one of the slides in Targhee Creek and got an ECTP13 on the lower of two well defined surface hoar layers. 

Riding today it was quite dramatic how much stiffer the slab is than it was the 10 days ago. Instead of just trenching through the whole snowpack you now mostly ride on top until you dramatically break though. We got a couple of shooting cracks while approaching our snowpit site, but they were not nearly as dramatic as the cracks last week. 

There was low visibility at Lionhead with a thick fog engulfing the ridge. We rode to Ski Hill and dug a pit on the south end. As we approached our pit site we noticed a recent avalanche on the steep center section of ski hill. It looked natural, possibly rider triggered in the last 24 hours, 14-18" deep, 225' wide, 200' vertical. SS-R2-D2-O.

Our snowpit had a layer of well-preserved 10-20mm surface hoar below 14" of snow (measured 2.45" SWE in 14" slab). Below that was soft facets, another layer of surface hoar, and more soft facets. We got ECTP4, and PST22/100end on the upper layer of surface hoar. The nearby avalanche probably failed on that surface hoar layer. 

We went to look a little closer at the avalanche from a low angle (25 degree) slope above. While approaching we had a large collapse and shooting crack.

A group of riders in the parking lot saw a similar depth recent avalanche a little further up the ridge.

The snowpack is very unstable and avalanches large enough to bury or injure a person are likely to be triggered on any steep slope.

It was snowing lightly all day with calm wind and overcast to foggy skies.

Snow warmed up significantly and felt heavy compared to a few days ago. Dug a snow pit on on an easterly slope.  ECTP 11. Didn’t notice as much cracking as a few days ago. 

We dug pits and rode on Sawtelle Peak. At 9,100 feet we had unstable test results (ECTP13 x 5; ECTP10 x2; CT4, Q1). When the clouds lifted we could see a crown of a snowmobiler triggered slide that occured yesterday. It broke on the buried surface hoar and facets about 1.5 feet under the surface. Recent snow and wind-loading has created dangerous avalanche conditions.

The avalanche:

Multiple remotely triggered avalanches. Lots of shooting cracks and visible whomping(poofs of snow dust). 

Triggered from over 140 yards 

From facebook message: "Multiple remote triggers across this slope."

Up Targhee Creek, near Lionhead Ridge. 1/18/24

From FB: Taylor’s Fork today, 8-10 inches of new snow last night. A few small slides but tons of cracking.

Rode up Denny Creek and out along Lionhead Ridge through Watkins Creek to the divide with Targhee Creek. Saw evidence of numerous older avalanches along the ridgeline and in lower steep meadows that likely broke last week (1/10-1/11). The crowns of these slides were blown in, but would estimate they generally broke 1-2 ft deep. Some broke quite wide ~1000 ft. Saw a couple smaller slides that looked to be a bit fresher as well. 

Got a number of collapses and shooting cracks as we rode today, shooting out 20+ ft. 

Stopped and dug a pit at the crown of an avalanche that broke on the north end of ski hill (likely during last weeks warning). Broke ~1 ft deep, 50 ft wide and ran 100 vertical. Another similar slide broke at the same time on the south end of ski hill. Today, we got an ECTP12 on the surface hoar about a foot deep.

The snowpack remains unstable and human triggered avalanches (including remote triggers from a distance) remain likely. Expect the danger to rise as it snows over the next couple days. 

From FB Messenger: "Major fractures and shooting cracks across whole hillsides today. Dry Fork. Targhee Pass."

While riding today on Lionhead we saw several natural releases on steeper terrain Mainly on Targhee Peak. On all aspects of slopes we experienced large cracks and collapses that would extended 75 plus yards ahead of our sled. We did not venture into steeper slopes but it sure felt like they would slide easily if we did! 

I was cutting down a hill and this slide broke loose around 20 feet away, no one was hurt I’ll attach screenshots of where we were on maps and a picture of the minor slide. 

We observed widespread shooting cracks on all ridges and all NE facing slopes. Cracks would propagate up to 200’ in front. Heavily wind effected sastrugi conditions.

We rode into Lionhead today towards Lionhead Ridge. Cloudy with consistent snowfall through the afternoon. The wind was out of the west and was blowing snow around at all elevations. We stopped at Ski Hill and dug on an east-facing slope at 8000'. While isolating our ECT we had a failure 15cm below recent snow on a well-preserved layer of surface hoar (ECTPV). From here we transitioned to skis and continued up to the ridge. As we approached the ridge we experienced frequent collapses and shooting cracks that extended 20 feet in front of our skis. At a rollover, while breaking trail there was a collapse, and 3" wide cracks shot in all directions and the slab moved a few inches downhill. If this terrain had been any steeper it certainly would have been an avalanche. 

We continued towards the ridge and intentionally remotely triggered an avalanche on the steep terrain below the south end of the ridge. This avalanche broke 1000' wide, 18" deep, and ran 100 vertical feet to the trees. This avalanche likely happened on a layer of buried surface hoar similar to what we found in our pit on ski hill. Strong west winds at the ridgeline continued to blow snow and made for poor visibility but as we continued more cracking was seen and cornices were remotely triggered when walking near them. 

Snowfall and strong winds continued making for poor visibility at ridgetop. We skied back to the snowmachine and portions of our skin track had been filled in by the steady wind and snowfall. 

We toured up Lionhead Ridge from Targhee Pass for a nice Xmas day tour.  Was a calm and comfortable day.  Just beyond the first large opening above 8200', I veered off the existing skin track and experienced a sizeable collapse on the NE side of the ridge.  I'd estimate the collapse extended roughly 30 feet in either direction.  I continued along this path and experienced one additional collapse.  Fun day out.  We did manage to find some supportable soft snow on the shadier side of the compass (NE to E aspect) from 8200' down to 7600' for some fun turns.

We rode to Ski Hill and dug 10-20 feet north of where it looked like an avalanche class had dug earlier this month. East aspect, 8,500'. Snow depth was 65-75 cm and we had an ECTP30 on the weakest, soft facets 20-30cm off the ground. Poor structure. We suspect this slope had been collapsed at least once from previous groups. Surface hoar was buried below the recent 6" of snow and was not reactive in tests, but pretty easy to see in the pit wall with large 1-2cm crystals above near surface facets.

We rode further up the ridge to "Marge" and dug on an east-northeast aspect. HS was 70-85cm and we had ECTP14 on weak depth hoar/facets 30cm off the ground. Also similar findings of non-reactive surface hoar below 6-7" of recent snow. Interestingly, we also easily found surface hoar in hand pits on more wind-loaded/exposed parts of the ridge and it seemed to break more easily here. This is noteworthy because wind-loaded slopes with buried surface hoar can be a deadly combination.

Calm and sunny today with some recent drifting of the new snow, but plenty of snow to be drifted into wind slabs still.