Snow Observations List

ETCP 7. Broke on top of the facet layer mid pack. Only change that was noticeable from last week is the warming from the bottom up of the snow pack making nerd candy sized facets on the base of the pack. Domino surface hoar between facet layers not as present. 28degree slope. Fracturing present on roll over below into middle. Pit was dug down the ridge from the cornice release slide east side of prayer flags from last weekend.
 

1/20/2024 ETCP7. Facets were smaller and surface hoar layer domino layer between the bottom 8in facet layer and next 8in facet layer present. Pit dug east side prayer flag up the ridge from cornice release into middle.

Well developed (2-3mm) surface hoar observed at the S shoulder of Bradley Meadows (at the top of the skin track). Some of the crystals had already been blown over, but most were still upright.  

We skied in the Bridger Range where unstable snow was not widespread, but does exist on previously wind-loaded slopes. Weak snow exists on all slopes, and where a wind slab sits over this weak snow you can trigger a dangerous avalanche. Attached pit profile from Hourglass shows a wind loaded slope, and other pit profile is in more sheltered terrain.

Slopes without a slab on top of the weak snowpack are less likely to produce a slab avalanche, but even the slightest bit of a supportable slab could easily break on the weak snowpack. Also, the sugary, weak snowpack is easily entrained by smaller slides causing more powerful loose snow slides on sustained steep terrain.

Wind was moderate at the ridge, but not transporting any snow. Light wind below the ridge. Temps near to above 0 C. Broken to Overcast skies.

Great walk, much better travel than other areas. Started noticing cracking, collapsing, and whumfing around 7800' on east facing slopes. ECTP 11 on our stability test. Much better snow than bacon rind and other similar areas.

Whumping on approach when not is snowmobile tracks. Dug a pit on a north east face slope off the Miller creek road approach to daisy pass at ≈ 9000ft . Shallow snow pack 110cm. Ectp 10 60 cm from ground 26 deg slope. Choose to ski low angle south west facing slope with no terrain above. No recent natural slides were observed. 

Starting at  45°11'13.26"N /  111°27'36.92"W, the NNE slope slid  (likely rider caused 2 days ago).
The adjacent slopes at  45°11'18.09"N / 111°27'54.78"W further west were slightly newer perhaps the 26th or late on the 25th. Each ripped down to the ground at the crown. Severe instability was present even when cresting over the slope from the entrance through the regular access to cedar - still not broke open.

Heard two large whumpfs when heading up the low angle slopes of Telemark Meadows. Dug a quick pit and found it was collapsing 30cm (rough estimate) deep on the second weak layer from the top. Lightly snowing, not much accumulation.

Conduction ECT test. 
Observed two well preserved layer of surface hoar
1st layer- 45 cm below surface. 3cm thick layer of surface hoar.

Went for a tour up to Blackmore today. We observed a few natural slides that released in the past few days. Most had relatively small crowns being 1foot, with crowns around 50 foot and ran short distances. We observed a rather large crown near the Blackmore summer trail just below the saddle that also released naturally and looked to have up to a 4 foot crown.

Went for a walk on skis in the low-elevation meadows below Blackmore and Elephant Mountain. Observed roller balls and snow glopping to our skins. Dug on a small NE facing test slope at 7760'. HS 48cm, ECTN12 & CT10 Q3 up 27cm on what looked like an old layer of buried surface hoar. A nice day for a low angle walk. 

Similar to your complete ripout of the slope at the head of first yellow mule, this aspect pulled out naturally likely on the 25th - natural caused. No tracks around.

South of two top north west of trail intersection #20. (saturday 1/27)

rode low angle stuff all day, creek bottom is normally not visible and its down to dirt. The whole area (south of two top) seemed really shallow and west facing slopes were very windswept when exposed, but filled in down low.

We found that the weak layers are all over the place after the warm weather and rain. Super faceted snowpack everywhere we went and even in low angle trees you could stick your hand in next to where a snowmobile track was and break a slab off. When rolling sleds over on a small hill we broke off lots of big 3' x 3' chunks down to the old really deep  weak layer.

We did not see any avalanches.

From IG message 1/26/24: "2nd yellowmule. Main north facing ridge. Whole thing ripped out. Appears like yesterday, but unsure. Massive slide."

Toured up Republic Creek, skied both East and west facing. Dug three pits, two west facing, one east facing.  Similar results on all three.

Pit 1 W facing 8750

Hs 84 f

75 4f

63 1f

50f  ECTP 14

404f

20 crust

4f to f below crust

Pit 2 WNW facing 9750

HS 115

ECTP 11 @ 78CM.  January storm slab to December facets 1f to f

Pit 3 E facing 8500

HS 90

ECTP 10 60CM St January storm slab to December facets 1f to f

Slide right off groomed trail near Chimney Rock 

Looks like a natural slide on the SW face of Crown Butte/ Bull of the Woods pass. Spoke with some skiers that thought it slide morning of 01/25/2024.

Couple days old [1/23 or 24]. Better light on it today. S aspect. 9800'

19° at 11:00 a.m. under overcast skies but warmed up when the sun came out. 

(Photos by T. Parrie)

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. 

Skier triggered several small avalanches while skiing near the zimmer creek yurt and observed a large natural avalanche on Sheep Mountain.

From email: "

 I did not get a good photo but yesterday (01/24) skiing out of the yurt with friends noticed a large natural on the NorthEast facing bowl on Sheep Mountain. Similar size to the Henderson slide if not a little larger. 

~300 ft. crown and ran a similar distance (300-400ft?) 

Also remote triggered a few D1 avalanches over the past 2 days. Continous cracking/collapsing even in a day old skin track. "