Snow Observations List

Observed evidence of natural slide activity yesterday while snowmobiling Buck Ridge. First pics are on a northerly aspect off Sphinx near the wilderness boundary, second set of pics are south facing off Pioneer Mtn.

Approx coordinates of slide #1: 45.15872, -111.46923

Approx coordinates of slide #2: 45.22781, -111.46531

Was able to spot a deep slab avalanche from Gallatin peak, slab was at the headwaters of S Fork Hellroaring (N aspect @ 9800) Hard to tell when this released as it was a few miles away, I would estimate the crown being around 10 feet. Observed a small storm slab on a north aspect as well (1-2 foot crown). Also saw a few dozen wet slides that released earlier this week, some tearing all the way to the ground. 

This afternoon my group triggered a dry-loose avalanche on the north face of Big Timber Peak in the Crazies. The slide was about 12 inches deep, 50 feet wide, and ran about 1,000 vertical feet. Thankfully, no one was injured. We didn’t officially measure the slope angle but we’re estimating it to be in the 38-degree zone—prime avalanche territory. The slide consisted of new snow that fell during this recent storm. It hadn’t bonded to the thick crust underneath and released during the second skier’s run.

While skinning into Big Bear gulch, off Wisconsin creek, we encountered a couple of small whumphs in a flat meadow below treeline. We also encountered one instance of localized cracking within the trees, near the hollow created by a dead tree. At the top of the ridgeline there were small cornices, and we noticed significant wind loading higher up on Old Baldy mountain.

In our east facing pit, just below the Little Bear ridgeline, we found a large melt freeze crust complex near the surface, interspersed with layers of much softer snow and NSF. Below the stout crust layers, the snowpack drastically reduced in hardness, with fist hardness facets near 50cm from the ground. We had moderate CT results (CT 12 Q2 @140cm) within the crust complex, and more difficult CT results (CT 23 Q2 @30cm) within a layer of large (3mm) striated depth hoar near the ground. Our ECT test resulted in an ECTX, possibly indicating the strength of the crusts, which neither skis nor boots would penetrate through. Our ECT column did pull out of the wall as a cohesive block when we applied shear from behind. Our pit profile was submitted through Snowpilot.

Based on these observations, and the warming we believed would occur later in the day, we decided to not ski off of Old Baldy mountain, and rather took some laps at a nearby low-angle meadow. 

Pretty much the entire wall skiers right of the prayer flags back into beehive slid. Wet slide. Multiple crown lines and long running. 

Photo from IG 4/13/23: @waxeman

Small storm slab off the steep drift on skier's R/skinner's L side of upper Thunder Road. Also felt some cracking and collapsing when I (briefly) stepped off the skin track to get to the top of Pierre's Knob. 

skinned up to the ridge and observed 5-9 inches of new and accumulating snow forming into wind drifts that were highly reactive. Multiple remote triggers occurred while traveling N on the ridge, propagating  both on W and E faces of the ridge. Both Hidden and Northwest Passage slid with little effort down to an icy bed surface. Debris at bottom of hidden was substantial but great skiing. 

Pics below of a natural wet slide that came out of Close Call yesterday afternoon (4/11/23), debris ran to the bottom of moonshine.

From 4/11/23: Yesterday (4/10) Colters released a wet slide (approx 1-3pm) that filled the top of the wiggle and left debris 300ft past the south bowl traverse.

Today Stupor had a similar sized release just after noon.

The best noted natural release was a wet slab release on the southern edge of the football field that put a pile of debris below the cave.

Although I only photographed North Bowl slides that ran very far, most of the chutes showed signs of wet slides running from the ridge. These were both in the bowl next to PK and north bowl.

From Big Sky Ski Patrol: "Temps remained a little cooler than yesterday and generally topped out in the mid 40’s F. That didn’t stop the free water from moving
and continuing to destabilize the snowpack, primarily on solar aspects below 10,000’. Near full depth to full depth wet loose avalanches continued to naturally release in what was left of the A-Z’s as well as LRT which had not seen any activity yesterday."

We rode up to Lulu pass, around the back of Fisher Mtn, behind Crown Butte and out Miller Creek south of Crown Butte/Daisy Pass. The upper snowpack was wet, but supportable. We dug down about 3 feet in a meadow in Miller Creek. HS 255cm. The snowpack was wet in the top 20 cm. -1.5degree C down 20cm and -3C down 60 cm. Still dry 40 cm below surface.

Wind was strong out of the southwest. Skies became mostly cloudy around midday, but seemed to clear slightly in the afternoon. Temperatures in the high 30s to mid-40sF.

There were maybe 6-10 D1.5-D2 wet loose slides scattered around the area that we could see, similar to attached picture of Crown Butte (We could see Miller Mtn. east and north, Scotch Bonnet, Henderson, Crown Butte, Abundance, Wolverine). At lower elevations where the snowpack is shallower, closer to silver gate and the northeast corner of the park, there were some deeper wet loose slides (D2) and a couple small wet slabs (photo). I would estimate most of these happened yesterday (4/10). Today, a D1.5 wet slide buried one lane of road in YNP on a steep, treed ENE facing slope at 6900'.

From IG: “Couple shots from today In the cooke area.”

Drove Bridger Canyon to Seitz road around 5pm on 4/10. Saw 4-5 D2 wet loose, plus many D1 wet loose. No huge slides or widespread large wet activity, yet.

From email: "This afternoon en route back to Livingston from Idaho, lots of slide activity at all elevations…

The first picture is the cornice collapse. One block in the debris pile was probably the size of my airplane - a giant ass snowball. 

The next few photos are wet slab a mile north along the same ridge, location: approximately 1-2 miles SW of the coordinate photo (it took me a minute to get cords up). Elevation of both approximately 9,800-10,000. 

Too many point releases to count in every range I’ve crossed today…"

While descending from a trail “run” (definitely more of a post hole) up towards Baldy, I saw a medium-sized wet slide on the eastern side of the ridge underneath some large rocks. The slide was roughly 15-20’ across at the portion I could see and traveled several hundred feet down the mountain. I could hear trees snapping (sadly in the video I don’t think you can, as my breathing is way too loud) and watched the avalanche move for almost a minute. I was very thankful for my careful route finding and avoidance of steep slopes! 

~ (45.7311237, -110.9639991)

Big Unit of a avalanche, photo taken from the Seitz road.

Today we observed wet loose avalanche activity on the southerly aspects in the mountains around Pioneer mountain. We also observed one dry slab avalanche on a NE aspect of Sphinx mountain at approximately 9,000’. 

We toured in Hyalite today. By 10:30 in the morning we saw wet, natural avalanches coming down east facing cliffs. We also saw several pinwheels from yesterday. By noon we were at 9,900' on a SE facing aspect, and the snow surface was wet at this altitude. Once we were down at 9,000' the top 8" of snow was wet, and it was beginning to move as a slab on small rollovers.