Snow Observations List

From Email:

"Observed a fresh natural avalanche this afternoon on Woody Ridge. The avalanche occurred on a NW aspect, around 9200' (likely last night). I'd estimate the size to be 1-3' deep, and about 100' wide. 

No other avalanche activity observed today.  (ski tour up Republic Creek this morning, low visibility while I was up there).

No collapsing. Minor cracking of the fresh, dense wind drifts, though they felt quite stubborn.

New snow:  about 10", dense/ rimed forms."

From email: "Saw this recent crown while xc skiing out above Mill Creek today.  It's on the east-southeast aspect of Peak 10526 east of Emigrant Peak at ~10,200'.  In what I like to call the Arrastra Ridge Avalanche Observatory Plot*.  The photo is taken approximately 5 miles in line of sight from the crown.  It is roughly 1000' wide.  If I had to guess, the crown is 10'+ tall—definitely a very destructive avalanche. I won't venture a guess on the rating.  I'd bet good money it ran all the way to the lake at the head of Burnt Creek and rearranged some timber.

*If one wanted to create a laboratory for observing large, regularly occurring naturally triggered avalanches, this would be one of the best locations in SW MT."

A group of skiers saw a natural avalanche on an east, facing slope off of Naya Nuki Mountain in the Bridger range. It likely avalanche early in the morning on April 2.

From IG: A group of riders reported seeing three new natural avalanches on April 1. 

From IG: “North meadow creek tobacco roots today“

Experienced a very large whumpf on the Middle Basin Ridge at Beehive.

We had just finished digging pits in the first large open section of the ridge and one of our skiers was jumping on the snow above the pit when there was a large whumpf. We guessed that the whumpf could have extended out to be about 100 m total(of course this is an estimate), but the point is that it was very large. One other group experienced two separate smaller whumpfs about 200 m away on a different section of the ridge.

The large whumpf occurred at approx. 9020 ft on a west aspect. 2 smaller whumpfs occurred at approx. 9030 ft on south/southwest aspects.

We rode to the Taylor Fork Weather station, then to the Wilderness Boundary above Beaver Creek, and then through Sage and Carrot Basin. There was 13-14" of new snow throughout the area. At the Wilderness Boundary we saw several R2-D2 avalanches on a NE facing ridgeline above Beaver Creek. We dug a pit on a SW aspect at 8,800' that was 9' in depth (HS: 279 cm). We had an ECTP 11 at the interface between the new and old snow. We also had an ECTP 24 on a layer of 1.0 mm facets sandwiched between two melt freeze crusts. These results and the recent avalanche activity highlighted the instability that exists from this most recent snow. When we were leaving our pit site the visibility improved, and we saw  a R3-D3 avalanche in a high alpine bowl. This avalanche confirmed that deep slab avalanches are still a concern for our advisory area.

We dug a pit to the ground (260cm) on the west wall in Beehive Basin to target observations for the Deep Slab problem. Attached is a SnowPilot graph of the layers, hardness, and grain identification. We performed a PST but did not get any results on the deeper facet layer, possibly due to the column not being fully isolated in the 260cm pit. 

We skied/snowboarded in the Lionhead range today and dug a pit on a southeast facing slope at 8900 feet. There was about 3" of fresh on top of a 3/4" thick crust. Then about 11 inches of 1-4 finger density snow, a hard 3/4" thick crust, a 1" layer of snow, and a third 1/2" thick crust. Below this was 30 " of one finger density snow to the bottom of our pit, (and 32" of snow below that).

We got ECTN4 at 6" below the surface along an unidentified thin layer, and ECTP11 that slid on top of the second ice crust (about 14" below the surface).

Riding conditions were better than the crusty layers might suggest. We stuck to the trees, less-than-30-degree slopes, and avoided slopes leading to terrain traps. We did not observe any avalanche activity.

Our party of 6 stayed at the Hellroaring Creek hut over the weekend. The winds and snowfall were intense, with the snow turning more graupelly by mid Saturday.
We dug a pit on a southerly aspect of Mount Nemesis, near the hut around 8000.’ We noted the complex layering, including a weak layer about 20” down that failed on the 23rd shovel hit. 

On Sunday morning the sun broke through for a bit and allowed us to view the widespread avalanche cycle that occurred overnight on all aspects. Across the creek, we saw a large crown (approx 3’ in depth) in the meadows. 

An avalanche that occurred on Nemesis’s south face ran from mid mountain all the way into Hellroaring Creek, running over our old skinner. 
 

The natural slides on Nemesis’s north face were some of the biggest we have seen in any slide, knocking out a lot of trees towards the bottom.  

Large natural on the E facing head wall above ainger lake. One smaller crown above the large main crown, broke on a deep layer. Debris ran past the lake. 

Winds started cranking this afternoon in the alpine and ridge tops. Lots of snow being transported around. Ski and skin tracks were disappearing close to the ridge between laps. 

ECTP 22 & ECTP 27, down 50 and PST 75/100 end, down 50 & 80 at 7800 ft on E aspects on the ramp above Bradley Meadows

PST 45/100 end, down 180 on E aspects at 7700 ft on E/NE aspects at N end of the top of Bradley Meadows 

Toured into Frazier Basin today and noted a few instabilities. First, on our approach, we experienced a loud "whumph" around 7000' on an East facing slope. Second, we saw a large natural avalanche above Ainger lake (E-SE facing) that ran from near the top of the ridge itself to propelling debris up, over, and past the lake. The crown ranged from 2-5ft high spanning 400-500ft across the face. Lastly, the wind was whipping and transporting lots of snow. As we gained a North-East facing ridge around 8500' a couple of pole/hand pits reviled a 4" pencil hard wind crust. Spring is in the air but it is still very much winter out here.   

Saw this crown from a distance today. Possibly natural R3-D3 on ESE aspect, likely caused by wind loading. Unsure when it occurred, but crown looked large and debris ran into the flats mowing down some small flag trees. 

We were forced to turn around yesterday on emigrant peak. We heard 2 large wumphs occur under our feet while skinning up and a visible crack was also seen. We dug a pit and obtained a score of 14 and it propagated all the way across the snow pack. The snow near the ground is very sugary and weak. This was on a SE facing slope at 7500 feet. 

My ski partner and I toured into Frazier Basin on Saturday, April 1st. We observed obvious signs of wind loading as we made our way up from Fairy Lake to the Frazier ridge. We found a crust layer a few centimeters thick that was widespread throughout the basin. The crust was not shooting cracks as we moved but hand pits showed that it was cohesive and easily breaking on the soft snow below. My ski Partner popped off a small wind slab that had enough energy to knock him off his feet. This was the only slab we found that moved after skiing three lines on different aspects. The wind slab that broke was just below a ridge in a bowl feature that probably experienced more wind loading than most other areas in the basin. We also observed an old avalanche at the end of the basin possibly from a cornice fall that ran the whole length of the slope down to the trees in the center of Frazier Basin. Overall it was not feeling like a spring snowpack and you should continue to be skeptical of multiple layers in the Bridgers. 

We were snowmobiling up portal creek today near the hidden lakes trailhead and I set off a small slide remotely by riding below a small ridge. The slide was about 3 feet at its crown 30 or 40 feet wide and ran about 40 yards. It just came down to where my track had crossed underneath. Everything was fine and we stayed safe and continued on with our plan and had a nice day.

This natural avalanche was observed in the afternoon around 1500. It was not seen earlier in the day and is thought to occurred at some point after 1200. It was seen from a distance on Pioneer mountain. It occurred on an E facing slope around 9600’. Active wind transport was noted on the ridge line above the avalanche. It looked to be around a R3-D2.

Toured in Beehive, Middle, and Bear Basins. In hand pits on W aspects we observed soft slab moving easily on a thin layer of facets over a melt-freeze crust buried about 40-50 cm. We dug on an E aspect at 9275' in Middle Basin and got ECTP24 on the same layer. Kept our objectives mellow. Did not observe any avalanche activity.