White Wing: Deep Persistent Layer, Wind Slabs

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SNOWPACK OBSERVATION
Submission Info
Forecaster
Thursday, March 8, 2018 - 12:00pm
Red Flags: 
Recent loading by new snow, wind, or rain
37° 44' 18.0528" N, 119° 2' 12.0984" W
Snowpit Observations
More detailed information about the snowpack: 

Toured to the NE shoulder of White Wing expecting to test the deep persistent layer and see both wind slab formation and low elevation loose wet activity. Hit all 3 perfectly. Dug a profile at treeline at 8500' on a NNE aspect and got results that indicated that the facets at the bottom of the storm snow are still capable of both fracture initiation and fracture propagation; the bottom of the snowpack in this area is genuine depth hoar (see attached profile). No whumphing or cracking today however, so it seems that this layer is becoming more stubborn. Pole probing up to 9600' on N and NE aspects seemed to confirm the general snow structure found in our profile.

Light to moderate SW winds were actively loading N-NE-E aspects down to even 8500' all morning (see video). Kick test results had some 1m long cracking in 1F hard wind slabs that were between 5 and 30cm deep on top of F hard decomposing and fragmented grains from the storm (see photos). Wind loading was widespread above treeline. Wind slabs were generally thin and stubborn locally. We turned around at 9600' to ski the soft snow in the sheltered N aspect trees rather than breakable wind board.

Saw small rollerballs on low elevation (8000') E aspects late morning and some large rollerballs released from the rocks above us on a W aspect as we were taking a break mid afternoon (also about 8000'). See rollerball photo. The snowpack seemed to transition from spring melt-forms at the surface to cold winter wind affected snow at 8500', treeline locally.

No other signs of instability today, although plenty of fresh hollow sounding wind slabs and short cracking was a little spooky near treeline and above.

Snowpit or crown profile photo or graph: 
Snowpack photos: 
Snowpit videos (tests, etc): 
Weather Observations
Blowing Snow: 
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Had driven to ski out of Rock Creek this morning, but once we were there it was clear that we would have to ski or walk a long ways before we were on deep enough snow to really ski. Visible snow transport at ridgelines from Mammoth south to Rock Creek on the way down.

On our way back to Mammoth from Deadman Summit this afternoon there was no visible transport.

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