sherwin storm instability

From Old Mammoth Road closure to top of Sherwin Ridge via normal ridge track
Submission Info
Saturday, February 2, 2019 - 12:00pm
Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Obvious avalanche path
sherwins 37° 36' 48.4308" N, 118° 59' 35.4372" W
Snowpit Observations
More detailed information about the snowpack: 

HN24 60cm @ 9000ft by 1500hrs in wind protected north facing below treeline terrain. Storm Slab at this elevation and below showed wrong side up structure but sensitivity of this in storm layer seemed to be decreasing in the 3.5 hours we were out. New old interface did not show signs of strong bonding in collumn tests, it also exhibited propigation potential.

Above 9000ft wind slabs were very touchy on NE-N-NW facign terrain up to 90cm thick. Wide spread shooting cracks was observed. Slope angles 30 deg and below were not steep enough to slide.

Atop the Sherwin ridge we remote triggered one SS- ASi-DI-R1 wind slab on a steep convex roll. Slab dimensions 1'x30'x 60' down slope onto lower angle terrain. We also triggered a SS-ASi-D1.5-R2 wind slab in Poop Chute (see attached photos). Slab dimensions 1'x40x~300'.  Cracking was quite predictable above treeline easily triggered from shallow places in the new slab.

Slope angle was critical today, with this much new snow it seemed slopes steep enough to provide good turns were also steep enough to produce D2 avalanches near and above treeline.  

Stability tests did not hint to basal facet layer waking up just yet with the new load and we did not experience any collapsing or cracking that felt it was this deep in the snowpack.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
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