Avalanche Activity

We skied into Beehive Basin today and found unstable snow. The bottom half of the 1.5' snowpack is weak, sugary facets that collapsed with audible "whumpfs" as we toured up. We dug at 8,700' on a SE aspect (a few hundred meters up valley of Tyler's slope) and the snowpit revealed a poor snow structure and instability. Even though some ranges have more snow, the set up is the same: weak, unstable snow underlying new snow. Avalanches, whumpfs and cracking are warning us to be careful throughout our entire forecast area.

Skiers in Beehive basin observed a natural avalanche on Saturday 12/9

From email: "Solo skier that released a small pocket of snow at the bottom of Super Couloir - he was not caught and it was just the recent new snow and it didn't run far."

Riders in Taylor Fork saw natural avalanches on Saturday, 12/9

Skiers in the Southern Madison, Lionhead, and Northern Madison areas experienced widespread cracking and collapsing on Saturday 12/9.

From email: "LOTs of collapsing again today while breaking trail on low angled S, E and W aspects.  Some collapses were quite large (100'+ diameter)."

From email "Observed a fresh slab avalanche on Mt. Henderson this morning.  E, SE aspect, 9,900'. I skied up to  investigate it and would estimate the size of the crown to be 2-4' deep and about 80' wide. Somewhat surprised by the size relative to the starting zone. Likely a natural avalanche (from about 36 hrs ago), but there were fresh sled tracks in the vicinity from yesterday, so possibly a remote trigger."

Big Sky Ski Patrol intentionally ski cut an avalanche breaking on the weak snow near the ground during avalanche mitigation work on 12/8/23.

From email: "[An avalanche] released on a ski cut, breaking on facets above a basal crust, easterly aspect, just below tree line."

Cracking and collapsing reported across the advisory area in the Bridger Range, Big Sky area, near West Yellowstone and Island Park, and near Cooke City.

Upon descending climbers saw two recent natural avalanches in the Dribbles Gully. These avalanches were failing within the new snow. 

From IG: Pocket I set off between finger 2 and 3 at Bridger Bowl just above the road. Finger 1 had someone ski it while we were hiking and they got a face wide crack.

From GNFAC: We rode up Daisy Pass road... saw a couple 8-10" deep natural avalanches on the steep slopes above Miller Creek that probably ran in the last 24-48hours. We had multiple collapses on the NE facing slope where we ski toured to dig our second pit.

From text message: "The attached picture is a little slide that went off when I was doing small turns on an adjacent slope. That's Beaver Slide! There was more small slides south in the trees. Heard whumphing here and there." Photo: J. Onken

User comment on FB: "Lotta slides in black canyon island park."

From FB Comment: "We were seeing shooting cracks in the snow Sunday in the Black Canyon area."

Was splitboarding up near lions head ridge today. Made some bad decisions and kicked off a good slide in a NE facing chute. Was with 2 buddies, 1 of which skied the line 3 weeks ago.  Underneath about a foot of new powder snow there was a firm crust that seemed like it was old  hard windslab in the gut of the chute, and I think a sun crust on the riders left side(East aspect). We had 2 spots where we were planning to re group at, first was a small cubby area right before a slight rollover about 75 ft from the top. I dropped first, made some turns down toward the pulloff, as I pulled in, I triggered a good size slab that propagated maybe 40-50 ft across, at the rollover as I carved into the pulloff.  Pulled  all snow  out of the chute down to the ground. Seemed to have failed on sugary facets on ground/ice crust close to the ground... 

Skied around Mt. Henderson today. Was finding around 28-35 cm of new snow at 9k'. Perhaps 10cms in town. Light density.  Minor wind effect. Partly cloudy morning, turning mostly cloudy. Cold temps. Calm to light winds where I was, but lots of snow was being transported off the exposed ridgelines south of town. Quite a bit of cracking of the new snow this morning while breaking trail and while skiing, even though the wind effect was still Fist hardness.  A couple of collapses noted as well in the deeper drifts.

Went into the Lightning/Taylor Creek area of the Southern Madison’s in search of some powder skiing with the new snow. On our ascent toward Woodward Mountain via the backside, we found fresh snow varying from 2 inches at the trailhead to foot deep lightly drifted areas in the upper elevations. In the protected low angle gully we ascended this new snow sat atop either rocks or a very stout wind crust. The latter of which made for great skiing. We descended Woodward top down and assessed the possibility of thin (3”) wind slabs being reactive on the stout wind crust as the Woodward side seemed to have received a lot more loading from the storm’s E winds. As we rolled over to slightly steeper terrain, I noticed the snow stiffening just below my skis and gave it a few hops where I intentionally popped the pictured slab. With this information, we decided to carefully traverse to more protected trees and descend via a less wind loaded and hazardous route. We ski cut from tree to tree triggering a few more of these very small slabs before finding wonderful powder skiing lower on the mountain where the wind had significantly less effect. 

All of the slabs were 1 to 4 inches deep and propagated 5 to 15 feet wide. None of them possessed the mass or were on steep enough terrain to overcome and slide over the stauch wall. Overall was a great lesson in mitigating hazard and we were rewarded with some great turns. 

From FB message: "Hi! I’d like to report 2 natural slides that were witnessed in the Flanders fork of Hyalite on Friday 11/24 on the east facing aspect of the canyon. Both avalanches came from a single snow field above “Bobo Like” ice climb. These slides happened at approximately 7:45am and 8:15am"

Skiers reported triggering an avalanche on the east face of Mt. Blackmore on Sunday.

Avalanches on Henderson Mountain near Cooke City were reported via instagram on 11/9/2023. Estimating they occurred a day earlier. 

From message: "on Henderson in Cooke just above the lulu trail. It was surprising to see so much activity"

From observation: "Skier triggered windslab in the Great One off of Naya Nuki peak, skier was carried 15-20ft before arresting. Slide was triggered roughly halfway down the couloir where the right wall dips away exposing the snow to wind. Hard consolidated snow over facets, roughly 1-1.5 ft thick, ran about 50-100 ft before pouring over the cliff faces below. North- northeast aspect." 11/8/2023

A hiker at Bridger Bowl noticed a small, loose snow avalanche near the Apron. Noting that it was a, "Good reminder as to how little snow is required to have an avalanche!"

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

From obs. (10/21): "Was out alpine climbing today and observed the north face of Blackmore had slid already."