Snowpack

Mammoth Area - Stubborn Wind Slabs, Minimal Weak Layers

Clancy NelsonEastside Region
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Observation photo 1Observation photo 2Observation photo 3Observation photo 4Observation photo 5Observation photo 6

Quick report

Cracking
specific

I found stubborn wind slabs near and above treeline today. I traveled through all elevation bands on most aspects, looking at the 1/1 crust.

  • I didn't get much feedback from the crust. Not in 6 different snow pits on multiple aspects.
  • The surface on northerly slopes is faceting under clear skies and cold temperatures.
Localized cracking (not shooting cracks) under my feet on multiple aspects near and above treeline in stubborn wind slabs.

Weather

Air Temp
20s
Cloud Cover
clear
Wind Loading
none
Rain Elevation
NA
Recent Snowfall
0
Snow Avail For Transport
moderate amounts

Cool, clear, and calm. No blowing snow anywhere.

Snowpack

Surfaces:

  • Top 20-30 cm of the snowpack on sheltered east, north, and northwest aspects near and above treeline are faceting (FCsf). Average ski penetration: 25 cm.
  • Near treeline exposed all aspects: stripped by wind, sastrugi, or hard, stubborn wind slabs. Propagation in snowpack tests under wind slabs. See photo captions.
  • Above treeline: Northeast, north, and northwest aspects stripped almost bare. Stripped to the 1/1 crust on west and south. Hard sastrugi.

1/1 Crust:

  • Exists everywhere: all aspects and elevations.
  • The primary places in the Mammoth area I found large facets (1-2mm) around the crust were below treeline on east, north, and northwest aspects, where the snowpack was less than 150 cm deep. The overlying snow was soft (F-4F), and I got no test results. Crust down ~50-60cm.
  • Near treeline on the north half of the compass, the snowpack is thicker (160-200 cm), and the crust is deeper (average 75-80 cm). The grains around the crust are small, faceted, round grains (0.5mm RGxf). No test results.
  • Solar aspects near treeline: the crust was down only 10 cm. There were 1mm facets around the crust. The snowpack was capped with a melt-freeze crust. ECTN5 in facets above the crust.
  • Solar aspects below treeline: crust down 60 cm. Non-persistent grains around the crust. No results.