22-23

Photo attached of a fresh natural avalanche, just south of Cooke City today.  It appears to have run last night or this morning.  (photographed at noon)

we skied up to 9230 on a south slope of Miller Ridge in sheep creek basin.  Intermittent clouds and sun, no wind.  Much wind affected snow, cross loading.  2-4 inches of fresh snow.    HS at 9000 was 100-110cm.  Started finding wind slab on rotten base at about 8900 then at 9200 where slope steepened we observed 3-5 foot shooting cracks and turned around.  Slope was 27-35.  Had climbed thru whitebark regrowth from 88 fire.  

Snowboarder triggered this slide on a rollover on East Republic. Reportedly ran 80' wide, 1-1.5' deep. No one was caught.

Layer of greatest concern is about 30 cm down from the surface. Small grained facets on a crust that was reactive to shovel shear.

slab layer about 30 cm down (1 foot) released when a shovel was put behind it with a sudden pop and very little friction. 

Snowmobiled to 8200ft then skied up to 9000ft. Dug a snow profile to ground on NE aspect at 8800ft. Height of Snow was 120cm (4 feet). Multiple weak layers in the snowpack including one about a foot down and a thicker layer of faceted sugary snow in the bottom 2 feet of the snowpack near the ground. ECTN29 on a crust and small grained facets about a foot down from the surface, however that slab layer released when a shovel was put behind it with a sudden pop and very little friction, see grainy photo. Surface was faceting old powder which could be another weak layer when buried. Not very reactive in this spot at the moment likely due to lack of new snow in a while. However generally poor snowpack structure is not reassuring and will need to watch when this snowpack gets rapidly loaded by new snow or wind blown snow. 

Small slide off the Henderson ridge by the radio hut. Looks to have broken in the last couple days. GNFAC photo. 1/10/2023

Slide on Chimney Rock. The one on Chimney Rock (triggered Sunday, Jan 8th) was not big, but more indicative of weak layers at the ground. Chimney was 2 slides side-by-side, mid-slope, that likely went at the same time. These likely broke on facets near the ground. The snowpack was thin there. GNFAC photo.