Date of Observation: 01/03/2017
Name: Zach Guy
Aspect: North, North East, East
Elevation: 9,000 – 11,400 ft
Avalanches: 2 natural slab avalanches on NE aspects NTL, a D2 and D1.5. From the ridgeline, about 6 soft slab avalanches were skier triggered, ran on the storm interface, 1 to 2 feet thick. Most failed on buried surface hoar, a couple also failed on near surface facets. Two were D2 in size. The largest propagated 600 feet across a slope and down a ridgeline, and ran 800 vertical feet, about 18″ deep. Cornices were also touchy; we easily triggered 3 or 4 from a distance, and it looked like one failed naturally or was triggered by a group in front of us. Skier triggered some minor pockets on steep rollovers below treeline, failing on surface hoar layer 8-10″ deep.
Weather: S-1 to S1, about 2″ of accumulation. Moderate SW winds and snow transport, with brief gusts of intense transport. Overcast skies.
Snowpack: ~10″ of storm snow below treeline. Â Storm slabs up to 3 ft thick near treeline, up to 4F in hardness in heavily windloaded features. Observed several shooting cracks an one muffled collapse. Storm interface is either near surface facets or surface hoar, varies from slope to slope.
Skier triggered soft slab, ~600 feet of across and down ridge propagation. Skier top right for scale. SS-AS-R2-D2-I.
SS-AS-R2-D2-I
Touchy cornices. Give em a wide berth.
D1.5 soft slab. NE aspect NTL.
Checking out an 18-24″ crown on a north aspect NTL. Failed on surface hoar.
Natural D1.5 soft slab. NE aspect NTL.
Large cornice fall….looked to be skier triggered by group in front of us.
Buried surface hoar: Culprit weak layer in a lot of the slides observed today.
Minor cracking and small slabs below treeline, on surface hoar
Natural on Climax Chutes, debris hit valley floor. SS-N-R1-D2-I
Natural on Climax Chutes. SS-N-R1-D2-I
Shooting crack. 50 feet long. 2 to 3 feet deep. Not quiet steep enough to slide.