Snow Observations List

From IG: “Pine creek today, some small wind slabs and a full depth wet slide off black mountain”

Three clear storm layers and wind effect piling up larger drifts. Snow height at 9k ft averaged 85-90cm. The rain layer in the center of the pack creating a sheer surface that with more load could trigger the third storm layer.

Sent a couple emails to mtavalanche.com with pics of a R3.9D11 that just missed me by inches last year. Just a heads up about Cornices and slabs 

From email: “These pics are from last June 10-11, after the pass reopened on Friday. I was skiing the Gardner headwall at 5:30, solo, when this monster released. Yah. The initial cornice collapse triggered and entrained a secondary slab of varying thickness whose crown is seen in one of the photos.”

Snowmobilers saw a recent wet slab on the northeast face of Henderson Mtn. on May 20, 2023. Video attached.

Wet slab avalanche on Hollow Top Mtn., Tobacco Roots 

ENE facing slope at 8,800’

On May 14 and 15 we saw crowns and debris of wet slabs that ran naturally over the past couple weeks.

Scotch Bonnet, S aspect, 9800'; Sheep Mtn. SW aspect, 9800'; Crown Butte, SE aspect, 10000'.

Hard to say exactly when they all occurred. The slides on Scotch Bonnet and Sheep appeared slightly fresher, but could have been a week old.

Skier triggered slide in a steep, north facing couloir in the Torrey Peak cirque. Triggered with a ski cut, no one was caught. Slide failed on interface between the old snow surface and 4” of consolidated graupel that fell 5/11. Prior to skiing this chute, we had not observed any avalanche activity failing on this same interface. 

Natural R3-4, D4 ripped out a large chunk of the south face of Wilson during the last warm period I would assume. Debris everywhere and one large boat-sized pile even scoured a path further down than the rest of the debris. Looked to be a mix of wet loose and wet slab release from high up. Alpha angle at the bottom of the debris was 25 degrees

A natural wet slab avalanche that occurred just south of Cooke City yesterday May 3, around 6pm.

The slide is on a northerly spect around 8500'.

Pictures from this morning (May 1) but I’m sure these all ran late last week. They took out at least one or two skin tracks set during the big dump (40”) that ran right up the center.

Unconsolidated, dripping wet snow this morning mid mountain around 830 AM. Top 3-4” had frozen but soft by 830.

Natural wet slab avalanche, north of Cooke City, which likely happened on April 30th (observed May 1).

It's on a SW aspect, about 10,500'.  Crown estimated to be 4-6' deep.

While touring into the Dry Boulder Creek drainage, we noticed remnants of many recent wet loose slides, and one significant wet slab avalanche. The wet loose slides had occurred on all aspects, including low-elevation north facing slopes. I estimate that most of the wet loose slides we observed were no larger than R2 for their respective paths, and most were D2, with some large, high elevation slides, reaching a possible D3.

We observed the remnant of one large wet slab on an east facing slope at around 8500 ft. I estimated the crown to be around 500 ft wide, and 5 feet deep at its maximum. I estimate this slide was a R2 D3, with an unknown natural trigger.

We took these observations into account, staying off of solar aspects, and staying out of avalanche terrain once the snow began to soften.

A skier triggered a small (D1) wind slab near the top of the Peruvian. Roughly 1ft deep and 20ft wide.

Saw a number of large wet slides at Bridger Bowl the morning of 4/26. One running deep into North Bowl, and a couple other large slides in Bridger Gully coming off the ridge. These seemed to be recent -- likely from the past 48 hours. 

Yesterday 4/25, Walked to the top of Pierre's Knob. The snow was unconsolidated mush, very sticky skiing. While hanging out at the top shack I heard 3 large avalanches running in the south bowl, white out conditions so was unable to see how big the slides were they sounded like they ran a long ways.

On 4/22 at 12:30pm we were part way up the boot pack (now skin track) up from Bridger chair to the ridge. We heard someone yelling and looked over to see a skier caught in an avalanche just above North Bowl Road. The slide came to a stop at the road (they were on top the whole time), and the skier yelled that they were ok. Seemed like they were skiing alone but more of the party may have been out of view. We had not seen wet snow concerns until about 30 minutes before the incident. By the time we left bridger, most chutes had slides out of them.

Our party toured into Beehive on Saturday. There was about 20-25 inches of new snow on our approach in.

We dug a pit at approx. 8,700 ft on a S aspect. Our 280cm probe couldn’t reach the bottom of the snowpack, it was the most snow we’d seen in the zone. There was 60cm (24in) of new snow that was perfectly bonded the the crust layer below. The next 60cm below this was a mix of 1f to P hard melt-freeze crusts that showed now signs of instability.

Our extended column test resulted in an ECTX and showed nothing but stability within the new snow. We reached the summit and skied the S ramp of 10,602, it was deep. As we exited the basin there was significant warming that had taken place at lower elevations but no signs of instability yet.

Spent the day choking on DEEP snow in the meadows around Fairy Lake. Light to mod. showers all day with a brief lull around 330 which allowed a window of visibility into the upper elevation terrain: No slab avalanches observed which surprised me (hence the obs.), very minimal loose snow moving despite the impressive SWE totals. Some wind texture at upper elevations but the new snow appears to be settling out quickly in typical April fashion. 

At 5pm on 4/20/23 I dug a quick snowpit to look at the storm snow o the Bridger Ridge. at 8,400’ there was 36” of settled snow equal to 3.6” SWE from the last two days. Total depth was 311cm (~10’ 3”).

No cracking or easy triggered loose snow on small test slopes. Surface was getting more slab-like or cohesive. In general the snow was more stable than yesterday, but there was a ton of snow so still potential for big avalanches. Probably less frequent than the recent dry loose snow activity, but potential for larger slab avalanches or wet avalanches.

Stability of the new snow could become worse if wind increases and drifts the snow into dense slabs, or when warm temperatures and sunshine arrive later in the weekend and make the snow wet and weak.