Snow Observations List

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. 

We rode back to the recommended wilderness boundary through Denny Creek, Watkins Creek, etc. We saw the avalanche triggered by a ground of riders around the corner from Airplane Bowl. It was 150’ wide x 4-5’ deep and 150-200’ vertical. The debris was piled 5-6’ deep, certainly deep enough to bury or injury a rider or skier. This was a close call.

We observed several recent storm and wind slab avalanches from Lionhead Ridge but not other deep slab avalanches. The snowpack structure is similar to what we have seen in the past rides to the area, a 3” thick layer of facets 1-2’ deep and facets buried near the base of the snowpack. Avalanches are becoming less likely without new snow, but the structure will keep the danger heightened for a while.

Looking forward, there was surface hoar covering most slopes, and it is supposed to snow lightly through the week. We will be watching this for a possible new layer of concern.

Drifting snow on ridges at 7,850 ft E aspect.

Obvious Rime on trees 7,850 ft.

Distinct PWL cohesive with previous obs.

Went up to Flanders today, dug a pit at approximately 9800ft on an east aspect. Snow depth was 154cm, with about 20cm of weak snow at the ground. We also found a weak layer at 112cm, which had a planar fracture during our shovel shear. Had an ECTx result, and when prying the column it pulled out as a cohesive block all the way to the ground. There was also quite a bit of surface hoar growth from about 7200ft to just below the summit.

1-2cm surface hoar encountered near 8000’on NW through NE aspects in the Mill Creek region of the Absarokas outside Livingston.

At about 10 AM I was belaying my partner on the first pitch of Bobo Like in the Flanders drainage of Hyalite Canyon.  We heard a low rumble and a couple seconds later we were engulfed in snow that poured out of the the pitch 2 gully, and seemed to keep coming for about 5 seconds.  My partner, who was on lead, was lucky enough to be at the base of the vertical ice of p1, so the snow mostly went over his head.  I was off to the side and close to rock at the base and was engulfed in loose snow, but not buried or injured.  We continued up afterwards.  When I was at the top of the second pitch, belaying my partner up, another small loose snow avalanche came down as river of snow, passing me as I hugged the anchor, and washed over my partner while he was on the pitch.  We were fortunate to have both been in positions to handle these avalanches without incident or injury.  In retrospect, the clear day and blasting morning sun likely loosened the snow above the gully and funneled it all down onto us.  After the first avalanche, the sun must have kept moving onto new slopes above, releasing more snow.  Even with a moderate danger level in the avalanche report for the day, with natural avalanches unlikely, we happened to find ourselves in a very specific scenario, with morning sun and a dangerous terrain feature, that still put us at risk.  Hopefully we will use this experience to improve our assessment of risk, terrain, and evolving conditions in the future.