Snow Observations List

Triggered by BBSP

Skied the meadows northeast of Blackmore today. Saw numerous loose dry slides on the way up. Didn't see any wind slabs. No whumphs or shooting cracks. SW wind was pretty strong most of the morning. HS 240cm!

Two obs - two days ago I was poking around Mosier Creek drainage.  Weird thing was that there was no wind impact - no drifts and snow was still on all the trees.  Other than that, super weak snowpack with lots of collapsing.  In fact at the lower elevations, snow pack was ~24" deep and my dog was breaking through all the way to the ground (she is about 60#)

This morning I was up in Bear Canyon - only about half the snow (4") as on the south side of town by SMS.  Pretty bullet proof layer under the new snow, but it seems it came in wet enough that it adhered well.  It wasn't even sluffing off at the break over points.  Snow was not done at that measurement as it was still dumping when I left around 6:30.

While on a walk up the main fork of hyalite today I noticed a slide on the west side of the drainage south of the maid of the mist 

Climbing near the Silken Falls / Dribbles areas from 11:00 to 17:00, we observed strong winds throughout the day. HN was 7-12cm on valley floors, and as we passed the Dribbles on the approach we noted a 20-25cm stiff wind deposit near the base of the buttress was that 1F- in firmness.

Wind transport was intense throughout the day both in areas we traveled and visible plumes at alpine ridgelines with the amount of fresh snow available for transport —a photo will not do the experience justice. Due to the protected nature of the climbs we were on, it was hard to tell which direction winds were blowing from. We observed 15 to 45cm of snow in the gullies we traveled (N & NW facing, ~7600-8600'), with the average HS being 20cm. While there was limited wind stiffening at the surface of much of the snow in these gullies, wind slabs were not present in the areas we traveled. We did not travel to the very top of any gully system, so I cannot speak at length to the hazard at the upper reaches of this wall.

Looking out towards Divide Peak and the Divide Cirque at the end of the day, we noted 3 fresh crowns that were not present in the morning. These were D1 to D1.5 in size, breaking along the base of cliffs, and appeared to be wind slab avalanches from a brief peek through some glass. There was a lot of small loose dry activity that we observed across canyon at middle to upper elevations as you would expect with strong winds and fresh snow. All activity was in line with what one would expect given the forecast and weather inputs. 

We rode portal creek meadows as an exploratory mission as neither Kyle Marvinney nor myself had ventured there much. New snow from the previous storm cycle had settled to about 4 inches, but it was hard to tell due to widespread wind effect. Judging from the snow, temps up there have mostly stayed below freezing during this previous warm cycle (after Monday/Tuesday storm), though there is fairly supportable crust below the storm layer. winds were blowing consistently 10mph up high gusting to and estimated 25mph. We observed one small avalanche in the riding area that occurred before the recent storm cycle and seemed characteristic of other similarly sized avalanches we have been observing throughout the season.

We rode into Lionhead with the USGS and USFS snow chemistry, hydrology and soil science teams. At the top of Ski Hill we dug a snow pit and in stability tests we got an ECPT27, that failed on weak snow near the ground. 
From here we rode to Motor Hill via Denny Creek. While crossing below Lionhead Ridge we saw an avalanche in Airplane Bowl that likely happened a few days ago. This avalanche broke 12” deep and 100’ wide. 
Above Motor Hill we dug another snow pit on an easterly aspect at 8600’. We had unremarkable test scores of ECTX (twice) and a PST 63/100 end. We saw a similarly poor structure as our previous pit, with weak sugary snow low in the snowpack. 
This morning with better visibility we stopped at the Hebgin pull out and were able to see 3 recent avalanches along Lionhead Ridge that were likely the result of recent wind blown snow. 

Our snow pit results above and the lack of deep avalanche activity were encouraging and initiating failure is becoming more difficult. This will change with incoming snow and wind so expect the avalanche danger to increase. This storm will hopefully test the snowpack and we are curious to see if it results in widespread avalanches or is able to support the new and wind drifted snow. 

Toured up Republic Creek today. Went to the ridge below Republic Mountain and then to Woody Ridge. 
 

winds picked up throughout the day and by afternoon were moderate gusting to strong at treeline and ridge tops from the W,SW.

started lightly snowing around 1 pm. 

observed 2 crowns in wind loaded terrain. One at the end of Woody ridge on a north facing sub ridge (Peterson’s prow ) and the other on an East facing Ridge seen from the top of Wyoming bowl. 

Rode Sawtell past two days. Very wide spread stout slab formed under the new snow that’s fallen. Heavy winds have scoured new snow away in places and deposited pillows in other aspects. Dug a pit with ECTX results but did not two layers of concern. One thin buried facet layer about 60cm down and the thick melt freeze about 80cm down. HS was 160 on a SE aspect about 8300. 

Skiing some dog pow across Hyalite reservoir between 7200-7800’ on a NE pitch I got lots of whumphs and shooting cracks while braking trail. This was a shallower snowpack than most other areas, it was still easy to break into basil facets with skis on.

I was skiing inbound at Bridger Bowl today and noticed a small wind slab avalanche that failed on quarter saddle. I estimate comparing the photo to Google Earth that the slide ran 250 vertical feet and broke 100+ feet wide. Ongoing wind-loading and obvious instability. 

From IG: This avalanche was from this morning (02/28). It was windy and the gully was likely wind-loaded. One video shows the debris and crown. The pin on the map (below) shows the location of the debris.

We exited Bridger Bowl ski area via the gate at the top of the Alpine Lift, ascended Bradley's Meadow and The Ramp and dug in one of the Refrigerator Chutes on a NE aspect at ~8000 ft. We found a snowpack that made us pretty hopeful about the direction things are headed in the Bridger Range. Snow depth was 160 cm and we got ECTX results. At least in this location, the weak layers are starting to heal. The early January weak layer was 1Finger hardness. We are not at all confident yet about how widespread this is, but nonetheless, it is nice to see things getting better somewhere.

Winds were calm below the ridgeline, but we could see big plumes transporting in Wolverine Bowl. Yesterday's skin track was completed drifted in in some places.

Around a foot of new snow from the last couple days made for good riding conditions.

Touring from 6800' - 8800'  breakable crust - both directions! Lots of whumphing down low but then none above 84-8600'.  

From email: "We didn't see any avalanches on E Henderson or E Sheep with decent vis on the ride in. One large avalanche on a heavily wind loaded slope below a huge cornice north of Scotch Bonnet. That one looked like it broke deeper/in the old snow, about 100' wide. Also saw one wind slab on a small slope north of Long Lake. 14-16" deep, 20' wide, and within the fresh wind slab. "

We rode up Taylor Fork around Skyline Ridge towards Cabin Creek. We found 12" of new snow had fallen over the last 24 hours. With poor visibility, we were unable to see any recent avalanche activity except for a small recent avalanche that happened near Beaver Slide. This was right next to a much larger slide that Doug and Ian had seen on 02/14/2024. While riding back we had a good view of the backside of Skyline Ridge above us and again saw no recent avalanche activity. However, many slopes had been stripped by recent winds. Strong winds and a foot of new snow that fell onto a weak snowpack kept us off of and out from underneath steep slopes, and recent snow made for pleasant riding conditions. 

From IG message: “These are on the ridge between Miller Mtn and Sunset Peak on North aspect. All of the North facing ridge of Miller Creek up to Miller Mountain had similar slides too. The crowns filled back in overnight… The North facing ridge on Sheep Mtn slid as well, not sure on the trigger but a rider from another group send the following image of the Sheep slide“

Toured up the west side of Woody via Central Park approach. Moderate to high wind gusts at the ridge line. Skied a couple laps in variable conditions on Sub bowl and then returned to the West aspect for a lap down South Central . 

Traversed into the tube at tree-line roughly 9900’ and triggered a small wind slab. Crown was around ~1 foot deep and maybe 40 feet wide. Possibly stepped down a bit once in the tube and then ran for about 300 feet. 

HS-AS-D1-R1

Went up to the prayer flags today. On the ridge about 100yards below the flags I went to the end of the cornice and gave it a stomp. Triggered a windslab that propagated about 50 to the left. 
HS-ASc- D1-R1-I

The crown was roughly 1-1.5 ft deep in the most wind loaded area. 
Multiple slides have went on this slope already this year, some running a good distance down through the trees. 

We rode up the road to Henderson Bench and dug on a northeast facing slope at 9,670'. While digging it was clear how poor the snowpack structure was. It was difficult to dig through a 2 foot thick hard slab, but once through the slab I sunk to the ground through 1.5 feet of weak sugary facets. We had an ECTX. After some extra hits, removing 2/3 of the slab, and a few more hard hits, we got a dramatic collapse and propagation. The facets were F+ in hardness below a P+ hard slab. Although the weak layer was difficult to affect in this spot, finding the right spot on a slope to collapse the weak layer would produce a big avalanche, as shown by a rider triggered slide two days ago on Fisher Mtn.

We also rode up to Daisy Pass. Visibility was good enough to see most slopes, but in flat light. We didn't notice any new avalanches.

Snow was falling lightly (S -1). Overcast skies. Wind was moderate with frequent strong gusts out of the west-southwest, forming drifts along road cuts and convexities.