Photos

Photo: GNFAC

A 2" thick wind slab is cracking, whumphing and breaking easly in stability tests (ECTP3). This was seen in the Throne area of the northern Bridgers. Skiing and sledding was reported to be "awful" from the winds. Photo: B. Nobel
 

Surface hoar (aka. frozen dew) makes an appearance at the Yellowstone Club. It was seen on the ground on many aspects and got covered up by light snowfall. These crystals can become a weak layer when they are buried. Photo: P. Bodalski

Upper elevation, north facing slopes around Cooke City have a snowpack that's 5-6 feet deep. As the snowpack gets deeper, it will becomes more difficult to impact weak layers near the ground. However, if a slide is triggered on facets near the ground, it will carry a lot of volume and likely be large and destructive. Photo GNFAC 

Wind loaded slopes releasing naturally were observed in Yellowstone Park near Cooke City. Photo B. Fredlund 

A skier up Republic Creek south of Cooke City observed this large natural avalanche. The slope was heavily wind loaded and slide likely failed on the facet-crust combination near the base of the snowpack. Photo K.T. Miller  

Large chunk of cornice that broke off with this avalanche on Sheep Mountain near Cooke City. Photo: GNFAC

Large natural avalanche with huge chunks of cornice in debris pile. This occurred on a wind loaded slope on Sheep Mountain near Cooke City. Crown is estimated 8-10 feet deep. Photo: GNFAC

This avalanche ran naturally on a heavily wind loaded slope north of Sheep Mountain near Cooke City. Photo: GNFAC

Winds either scoured or loaded all exposed slopes over the last 48 hours. Winds blew from every directon at all elevations. This photo was taken up Hyalite in the N. Gallatin Range. Photo: B. VandenBos

Evidence of strong winds were everywhere yesterday. These ripples of wind blown snow are evidence of crossloading on slopes. This picture was taken up Hyalite in the N. Gallatin Range. Photo: B. VandenBos
 

The bottom 15cm of the snowpack consisted of large depth hoar crystals (4+mm). As we skied up we heard one large collapse on this layer and in our snowpit this layer failed at ECTP12 and 17. Either sign of instability (the collapse or the poor test scores) was enough for us to choose not to ski the steeper gully. Photo: GNFAC
 

This natural avalanche was observed on a W-NW facing slope off Woody Ridge near Cooke City. The slide likely took place on the 20th of December and was the result of a heavy wind load sitting over factes near the ground. Photo J. Logan 

This slide occurred on a west facing slope off Woody Ridge outside of Cooke City. The slide failed on facets near the ground and was the result of heavy wind loading. Photo B. Fredlund 

This natural avalanche occurred on the Fin outsided of Cooke City. The slide took place on an east facing slope and was the result of heavy wind loading. It appears the slide failed on an instability buried mid-pack. Photo B. Fredlund  

Mid-slope wind scouring from previous days high winds.

Jim Norlander, CGNF Snow Ranger, just installed the Friends of the Avalanche Center's Beacon Park off the main trail heading out of town toward Two Top. Stop by and practice!

Midslope wind scouring from previous days high wind events.

A poor snow structure of sugary facets at the ground could not support the new snow and windblown snow. This natural avalanche occured in the last couple of days. Photo: GNFAC