Snow Observations List

We rode into The Throne, and skinned up the ridge. While skinning we saw cracks in front of our skis in the 6” of new snow. The wind was gusting from the north most of the day–our skin track was filled in by the time we skied out. Where we dug, HS was 130 cm (~4 feet) on the NE aspect at 8,100 feet. ECTN 8 on the new snow, and ECTN 24 at a layer of graupel about 1 foot down from the surface. This layer was noted by skiers in Texas Meadows yesterday.

While skiing back to our sleds we triggered a small slide in a wind loaded pocket of snow on a ~35º, isolated terrain feature (SS-ASu-R1-D0.5). This was on a southerly aspect, at about 7,000 feet, 4-6” down on surface hoar, 15’ wide, 30’ vertical run.

While skiing around our boundaries I observed well developed surface hoar that was relatively widespread in undisturbed areas. The photo included seemed to go well with the fx. 

I came across this older avalanche yesterday when I was guiding a group in the Kirkwood area, it’s an area in the Cabin Creek drainage. It looked to be an older natural slide probably just after the last storm cycle a few days to almost a week ago now. After seeing the old slide and taking a look we found a safe slope with the same aspect approximately 300 yards away with the same NNE aspect, dug a pit and did an ECT test with stabile results.

Kirkwood

North, North East Aspect

Approximately 39 degree slope (Because of a creek with open water just below the slide, I couldn’t get close enough to accurately measure the slope)

ECTX…When digging the pit we could see what looked like 2 weak layers in the snow pack and a faceted layer at the ground. We had no failures during the test and even after the test when I pulled and pried with a shovel, the snow held together and showed signs of stability.

Recent low density snow was drifted into 10” soft slab from west wind, north of Cooke City. Skier triggered intentional on test slope. 

Same PWL's as observed in recent past. Newly forming wind slabs and a more recently formed 2 cm (very fragile) melt freeze crust at 228 cm. 

4-5 in. HST on top of melt freeze crust

A lot of blowing and lightly falling snow the past few days. Larger drifts forming on the NE aspect ridge line where we dug our test pit today.

CTH 192 cm above melt freeze crust

Submitted via instagram: "Ectp12 and 22 at 85 and ~25-30 cm (less planar) respectively on S aspect we did not ski and bailed from after initial pit ~300m away in slightly more protected terrain yielded ectN. Was dug adjacent to ~33-35 degree slope. Slope is located near the head of Flanders Basin"

Dug a quick test pit yesterday (2022-01-04) in Texas Meadows zone on a SW asp at 7800 ft. 

Had an ECTN21 down 25 on a thin layer of small (size 0.5-1) facets. Though it didn't propagate, the block sheared off easily and cleanly on this layer after the test.

Also got an ECTN26 down 17 on a layer of graupel ~1cm thick which overlay a melt-freeze crust ~1cm thick. The graupel was large, up to size 5.

We additionally noticed some surface hoar up to size 4 in isolated shady places, though much of it appeared to have been knocked flat from previous wind.

Extended column test at lat/long 45.84006, -110.93326, elevation 7698 feet, east facing, approximately 20 degree slope.  Depth of snow = 95 cm.  There were 2 obvious interfaces: 1) approximately 20 cm below the surface (ice crust) and 2) approximately 20 cm above gound, the heigth of the faceted snow.  ECTP18, shear quality q1.  The snow is noticeably dense/stiff.  We stayed on lower angle slopes, the skiing was good.

We rode into Teepee Basin first. We had perfect visibility and saw no avalanches. We dug on the far north ridge on a south facing slope: HS 105, ECTN25 on facets about 40 cm off the ground. There is a lack of recent ava activity and ECTN score, which point towards a snowpack trending towards stability, but the snowpack structure is still suspect: facets underlying a slab.  

Next we rode to a small and recent avalanche in Cabin Creek. We were alerted to it last night. Although it was steep and wind-loaded, it illustrated the lurking problem we are finding in most areas. Faceted snow is not entirely trusted. We did not see evidence of avalanches on Skyline ridge and folks are starting to climb.

Extremely crusty snow. Dug a pit and found three very defined ice layers around 5500ft. 

From instagram: "Right off the trail at tepee creek just before the cabin. A natural slide about 2ft crown"

The snowpack structure has deteriorated on Ellis since the last time I was there a couple of weeks ago, but without loading, it remains generally stable. I am less optimistic about future stability. All slopes were covered by a layer of surface hoar and near-surface facets. Light winds will do little today to disrupt the surface snow. Hopefully we get some wind that beats this layer up a bit before it gets buried. 

We felt that finding instability was unlikely today with ECTXs and ECTNs in the 20s in both our pits.

Rode through 1st, 2nd, & 3rd Yellowmules, into the heads of McAtee, Muddy, and Bear Creeks. Saw a small snowmobile triggered slide (~1ft deep and ~20x20 ft) at the head of Muddy Creek (NE Aspect, 9400 ft). Looks like it was likely triggered on Sunday (Jan 1st) in a shallow spot near rocks. No other avalanches or signs of instability. Dug on NE and SE aspects around 9400 ft (HS100-140) and found F+ to 4F facets in the bottom 2/3rd of the snowpack, but got ECTN21 and ECTX. 

Widespread big crystals of surface hoar (feathers around 1 cm in size). We will be watching to see if it is buried as it is potentially our next weak layer of concern.

Newly formed melt freeze crust near surface and wind slab continuing to form due to current weather conditions. Wind loaded slopes will continue to be a hazard along with PWL's.

We dropped in off the summit and my partner watched me from the top of the first cliff band while I dug below. HS 125cm. I got CT13, Q1 one foot under the surface which coincided with the natural wind slab avalanche from a few days ago. A CT16, Q1 failed one foot under that and a CT19, Q1 broke on the facets/depth hoar about one foot off the ground. Facets were F+ to 4F-. Slabs were 1F to P hardness. I was not happy about it the snow structure or test results. I decided to skin and boot back up to my partner and then head to the ridge. A big load an it’ll avalanche at the ground. It’s not great out there and the bigness of the terrain certainly increased my concern and effected my decision making, as it should. 

Widespread surface hoar in Hyalite observed up to 8200ft, mostly on E and NE aspects 

Had 7 sleds in a relatively small area on the south facing side of Taylor mountain at about 10k ft.

Group noticed a substantial wumph after sitting for less than a minute.

Don't believe it is cause for serious alarm as a snow pit showed relative stability. Just something we all noticed and talked about and to be aware of as the snow continues to fall.

1/3/23

From FB message: “Near Sage Creek/Sage Mountain in carrot basin. This was a east facing, wind loaded slope. Snowmobile triggered below the rock line. No burials.”

Did two extended column tests on the east-facing slope of Little Ellis, both pits being ~20 ft down from the summit. The snow surface was a layer of surface hoar on top of ~12 cm of new snow. Slope angle was roughly 23 degrees and each pit was 75 cm deep.

We were looking for this season's problematic and persistent weak layers in the snowpack and found them quickly. Our first pit produced an ECTP10 and pulled out all the way to the ground (the entire 75 cm slab propagated on top of a sugary layer of snow at the ground-bed surface). We decided to dig a second pit on the same slope to test again and got different but still unstable results. Our second pit produced an ECTP14 on a layer of sugary snow 30-40 cm deep, and then ECTN on the remaining column of snow (potentially due to a varying ground-bed layer of snow between the two pits – most of the snow beneath the fracture in the second pit was just sugar).

We chose to ski the ridge back to the Mount Ellis parking lot for lower-angle turns (which was our plan before digging the pit, but reinforced by our results).

Dug at 9000’ E aspect, HS 110cm ECTN7 down 35cm on .5-1mm facets. 1-2mm F basal facets in bottom 30cm. 2-4 mm SH throughout zone.