Trip Planning for Lionhead Range

Riders in the Lionhead area noted that a layer of feathery surface hoar is continuing to grow. If this gets buried by the next snowstorm it will become a new weak layer. Photo: G Ewsuk

Riders reported on 1/15/22: "Some surface hoar is forming on nearly every aspect at all elevations. over 1 cm thick in some areas." Photo: B. Rasmussen

Riders reported on 1/15/22: "Some surface hoar is forming on nearly every aspect at all elevations. over 1 cm thick in some areas." Photo: B. Rasmussen

Settlement rings around the base of trees near Cooke City, January 15, 2022. Photo: B. Fredlund

Ian Hoyer stands in the 7 foot deep snowpit we dug to look at layering and stability. Stability was good. We dug at 9300' off the Sawtelle Peak Road to keep tabs on stability since we put out warnings and basic information for this area on our Trip Planning page. Photo: GNFAC

A wind swept ridgeline at the head of Targhee Creek near Lionhead. 1/11/22. Photo: GNFAC

Cornices along Lionhead Ridge. 1/11/22. Photo: GNFAC

A layer of near surface facets is buried about a foot down on some slopes near Lionhead. 1/11/22 Photo: GNFAC

Small natural storm slab avalanche seen near Lionhead. 1/6/22. Photo: C. Leonard

The West Yellowstone Beacon Park is up and running for the season! 

Photo: J. Norlander (1/6/22)

This avalanche broke wide in a northerly facing bowl off Lionhead Ridge. It looks to have broken a foot or less deep. The propogation indicates a uniform weak layer, likely near-surface facets or surface hoar. Photo: B. Fuglie

A sled was recovered uphill of the 2 avalanche victims in the same area it was stuck. The sled was found with a probe line and is buried 3-4 feet deep. The avalanche crown can be seen in the upper slopes above them. Photo: GNFAC

The crown of the avalanche that killed two snowmobilers on December 27, 2021 was 300 feet wide and 4-5 feet deep. Photo: GNFAC

These are the two sites where the 2 snowmobilers were recovered. They were buried 4-5 feet deep in debris piles that measured 9 feet deep. Photo: GNFAC

Ian Hoyer stands next to the crown where we dug a snowpit and investigated the snow structure. The crown averaged 4-5 feet deep. Near his right knee is the layer of weak faceted snow that broke 40 cm above the ground. Above this layer was a thick slab of windblown snow. Photo: GNFAC

Dave Zinn of the GNFAC gets 3 layers breaking in his Extended Column Test. About 3 feet of snow fell in the last 4 days which got blown into wind slabs. The weight of the new snow is also creating instability on a weak layer of sugary facets near the ground. Photo: GNFAC

Riders in the Lionhead area observed 5-6 naturally occurring avalanches that likely failed on 12/15 at the tail end of a 3' snowstorm. Photo: S. Tyson

Located off Lionhead Ridge outside West Yellowstone, this natural avalanche likely released after the large storm ended Wednesday, December 15. This slope is SE facing and the crown is about 9,400 feet. Faceted snow at/near the ground was the likely weak layer that avalanched. Photo: GNFAC

Snowpack on Two Top Mtn. near Island Park, ID on 12/17/21. More than 3 feet of snow fell last week and it was right side up and generally stable. There is some weak snow and crusts near the ground, but we are not seeing signs that these layers are unstable yet. Photo: E. Knoff

A skier in the Southern Madison Range remotely triggered this avalanche in the Bacon Rind area from a flat bench above the slope. It broke over 50-75' away where the slope got steeper. Human-triggered avalanches are likely. Avoid steep terrain until the snowpack stabilizes. Photo: Anonymous 

From obs: 12/12/21: "Heavy wind loading from gusty SW winds and recent snowfall. Made for some touchy conditions. This was at 9100’ between Sage and Sunlight basins." Photo: JR Mooney

At Lionhead Ridge, strong winds are drifting snow into unstable slabs. On steep rollovers, we observed shooting cracks and one large collapse, or "whumph." With more wind and snow in the forecast, expect conditions to get more dangerous before they improve. Photo: GNFAC

New snow was blown into thick drifts that can be triggered by skiers or riders. Cracking like this is a sign that drifts are unstable and could slide on steeper slopes. Photo: GNFAC

From email (12/5/21) : "Small avalanche triggered while approaching ice climb in East fork of Hyalite basin. 

Another D1 natural avalanche was observed later in the day similar aspect/elevation

NE @7600’
SS-AFu-D0.5-I"

Photo: A. Schoening

Skiers on Mount Blackmore observed cracking within the freshly wind-loaded snow on a southeast-facing slope just below the ridge (11/24/21). Photo: J Schack

Snowcover on Lionhead ridge begins at about 7,000' in elevation on 11/16. Snowmobiling or skiing from Targhee Pass looks very thin and patchy. Photo: GNFAC

Taken on 11/16, consistent snow on all aspects begins around 7,000 feet. 1.5-2 feet of snow is found above 8.500'. Photo: GNFAC

From e-mail 11/7/21: "...Once in airplane bowl we saw multiple large slides that ran last night, syn-storm. Most of which came down from the East face of Sac. A few 200-300’ wide and running the length of the bowl.,,, attached is a grainy cell phone pic of the slides in Airplane Bowl." -Anonymous.

From email 11/4/21: "...noticed two small wet loose avalanches in the east facing bowl between Pomp and Hardscrabble Peaks." Photo: H. Darby

From e-mail 11/4/21: "Hiking up in the Bridger Range from Sacagawea Pass and noticed no faceting of the current snowpack. The snow near the pass and on the ridge is very wind affected as is to be expected and dropping into the bowl on the east side of the Pass the snowpack there has a distinct sun crust. Dug around a little bit at 8600 ft on a NE aspect and found a sun crust of about two inches with what felt like rounded grains below that. Even in the direct sun, the crust was taking a long time to rewarm and was pretty slippery..." Photo: H. Darby