Regional Conditions for Lionhead Range

A skier triggered this avalanche on Saddle Peak on Thursday, April 2. No one was caught. It appears to have broken under the new snow. Big avalanches in big terrain are usually unsurvivable.  Photo: GNFAC

The annual fundraiser, Give Big Gallatin Valley, will be held 6 p.m. on April 30 to 6 p.m. May 1. The Friends of the Avalanche Center are participating again this year!

This tree near the north ridge shows no signs of wind during the storm. Photo: PC

"I skied near Quake Lake today, and observed several signs that the snowpack has not adjusted to this last storm yet. While ascending, several drifts collapsed under my weight, and I observed a very recent natural slide on a wind-loaded, east facing slope at about 9200'." Photo: Sam Reinsel

This surface hoar crystal is almost 1.5 cm (each square is 2mm) and was the weak layer in a few avalanches on Buck Ridge (3/29/20). Photo: GNFAC

We saw this natural avalanche from afar. It was NE aspect and likely failed on a layer of surface hoar 1-1.5' deep. The Madison Valley is in the background. Photo: GNFAC

Sunday (3/29/20) skiers near Fairy Lake saw this cornice collapse that ran for quite a ways in October bowl. Photo: T. Gittins

From obs. (3/29/20): "Significant wind started building mid morning, forming even bigger cornices and wind loading many slopes. Noticed this slide on an East/Northeast aspect at the back of the bowl above Maid of the Mist creek, possibly triggered by cornice fall but unknown. Happened between 9:45am and 11:30am today, as at 9:30am it was not there, and when we returned to the spot around 11:30am the slide was visible." Photo: CP

Today on the east side of Lionhead Ridge we found a layer of weak, near-surface facets buried under a foot and a half of new snow. This is definitely something to watch out for especially on wind-loaded slopes. Photos: GNFAC

Enormous cornices overhanging Lionhead Ridge. Photo: GNFAC

Snowfall throughout the afternoon fluctuated between S1 - S5 (during brief squalls). The winds started out moderate and from the west but calmed by the last lap ~5 pm. The new snow (from last night/this morning) was fairly well bonded to the sun/melt-freeze crust below, but the storm came in subtly upside down. Today’s snowfall (accumulating ~3” while skiing between 1-530) was light. Right along the ridgeline, we triggered 4 predictable small storm slabs 4~6” deep on the upside-down storm snow from last night/this morning, but surprisingly not on the old crust. They were each 5-10m wide x 5m long and only ran ~5m vertically. Photo: Z Miller

This is a photo of a small roof avalanche near Island Park. Warming temperatures cause water to percolate through the snow which lubricates the sliding surface. Roof avalanches have injured and killed people in the past, just one more thing to worry about. Photo: M.E. 

Dave Zinn digs a hand pit along the ridge to assess how the new snow is sticking to the ice crust. Photo: GNFAC

Obs: "School bus size cornices over Easterly portions of Lionhead Ridge. It is hard to tell from the photo, but the largest cornices were about 20-25' tall. We dug a few pits on East Facing slopes between 9,000-9,500 ft with the worst result being an ECTN-21 however these Cornices are primed and ready to fall with the abundant sunshine and warming weather." Photo: JR

From e-mail: "Natural wet slides... caused us to back off our plan of heading that way and ski a north, shady aspect instead. On a southern aspect. 9000ft. 1:30pm. We dug a hasty pit and observed a weak layer about 1m down. The facets were beginning to round." Photo: K. Master

From IG post with #gnfacobs: "I triggered a small windslab, mid slope on the north face of Wilson. It was a a pretty stubborn slab that broke above me. Cross loaded from lookers right. 6-8” deep." Photo: B Gill

From IG post with #gnfacobs: "I triggered a small windslab, mid slope on the north face of Wilson. It was a a pretty stubborn slab that broke above me. Cross loaded from lookers right. 6-8” deep." Photo: B Gill

From south of Big Sky yesterday 3/17 about 9:00, just north of Buck Ridge at 8500'. Large surface hoar on northerly aspects. Photo: Spence

We dug near the top of Bacon Rind and found 155cm of snow. Our primary concern is with the upper snowpack. As it warms and wets we can expect an increase of avalanche activity on the ice crusts. Facets are still dry and soft at the bottom of the pack and I got this layer to break with an ECTP29. Photo: GNFAC

From e-mail: "...some wet loose avy activity observed today just west of Cooke City (south aspect, around 8200').  Overall though, minimal wet avalanche activity observed with this significant warm up..." Photo: B. Fredlund

Point releases across highway from Bacon Rind. 3/6/2020.

Photo: GNFAC

Point releases across the highway from Bacon Rind. 3/6/2020

Photo: GNFAC

Wet slide in Buffalo Horn Creek. 3/6/2020.

Photo: A. Norlander

From an email, "It did look like the east face of Ramshorn Peak slid pretty recently. The blowing snow and clouds weren't conducive to good pictures but you can see the crown line below and to the right of the summit. Looked like a cornice fall triggered it." Photo: B. Richards

Overview of an avalanche triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. Photo: GNFAC

An avalanche triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. The debris piled 8' deep on the road, which creates a terrain trap. Photo: GNFAC

An avalanche was triggered on 2/27/2020 at 8:30 p.m. by a groomer between Storm Castle and Swan Creeks in the northern Gallatin Range. The driver was ok, but the machine did a full barrel roll and was very badly damaged. Photo: GNFAC

From obs form: "While approaching Black Mountain from Pine Creek Lake.... We skied South aspect and as it warmed we triggered D1 R1 slabs that ran slow and short." Photo: T. Hoefler

From email: "Photo attached of a natural avalanche from yesterday, just south of Cooke City.  It's on an E, NE aspect, with a crown around 9,300'.  Looks like it occurred yesterday am, as a result of a cornice fall." B. Fredlund

Skiers saw this 2-4' deep natural crown on Sunday 2/23/20. Photo: from IG @skishot

From IG #gnfacobs post: "An avalanche from early Tuesday (02/18) morning caused by a natural cornice fall. Note the step down partway down the path. ENE @ 9700. Ran 1300’." Photo: A. Whitmore

Slide in Taylor’s Fork, crown of about 5-6’ and about 100' wide. Human triggered. Photo: Matt Seifert

We rode into Lionhead and found good stability. A sledder highmarked up the hill and then came down right next to us, confirming our results. Wind-loading from yesterday is still a concern, and so are the facets near the ground, although less so than a couple weeks ago. Photo: GNFAC

We saw a group of six snowmobilers who said they triggered these slides in McAtee Basin on the left side of the meadow on Saturday, Feb 8. I didn't see tracks up on the hill or sidehill tracks so they may have triggered the slope from the flats below. The debris runs all the way to bottom of the hill. Photo: K Peaslee

We saw a group of six snowmobilers who said they triggered these slides in McAtee Basin on the left side of the meadow on Saturday, Feb 8. I didn't see tracks up on the hill or sidehill tracks so they may have triggered the slope from the flats below. The debris runs all the way to bottom of the hill. Photo: K Peaslee

We saw a group of six snowmobilers who said they triggered these slides in McAtee Basin on the left side of the meadow on Saturday, Feb 8. I didn't see tracks up on the hill or sidehill tracks so they may have triggered the slope from the flats below. The debris runs all the way to bottom of the hill. Photo: K Peaslee

"Noted two SS-D1.5/2 naturals (presuming based on lack of any sort of tracks) on Wheeler, typical spots for these conditions, both SE aspect around 8000'." Photo: G. Antoniolli

"Noted several avalanches (NW aspect ~ 8800') off of Elephant that traveled quite far into the trees where the summer trail typically runs, all appear to be new snow, D1- D2 in size, average 2' crowns, running on old/new interface from  Feb 2. They appear to have run midstorm, sometime yesterday (photos 1,2,3).  Above 9000', W Winds were crafting fresh wind slabs that were most reactive on a midstorm crystal/density change that buried a layer of stellars ~ 1' deep in shallower spots,  topped with denser snow." Photo: G. Antoniolli

"Natural avalanche. North facing slope. Around half mile wide. Photos don't show half of the slide. Broke on the ground facets. Crown was between 3 and 15 feet deep. We didn't get a photo of the deepest crown. Ripped trees out around 5" diameter." Photo: Reed Malmstrom

"Natural avalanche. North facing slope. Around half mile wide. Photos don't show half of the slide. Broke on the ground facets. Crown was between 3 and 15 feet deep. We didn't get a photo of the deepest crown. Ripped trees out around 5" diameter." Photo: Reed Malmstrom