Professional Observation

Observation Details

Signs of Unstable Snow

Snow Stability

Key Points

Toured from Mammoth to June Mountain.

• Below 9500′ : Different breakable crusts dominated the snow surface. Solar aspects had a 4 cm breakable P hard MF crust with faceted, F soft, dry snow underneath. Shaded aspects exposed to wind had a 4F wind crust with the smaller, F soft facets underneath. Shaded spots, not affected by wind were soft. On a whole, snow surface seemed highly variable.
• Structure of the snowpack below 9500′ : 3 – 4 cm MF crust over 30 cm dry F soft snow over 1cm older crust, P hard. Over 30 cm dry snow 4F over 7 cm K hard rain crust. Below that 1F probably rounded grains.
• Above 9500′ the snow surface was more consistently soft. Soft, wind rippled snow alternating with more dense and smooth but still very skiable wind packed snow on open, northerly aspects.
• I did not see any signs of instability where we skied.
• I noticed two areas where glide cracks are developing. One on a S aspect @ 9600 ‘ above Deadman Creek and the other one in the usual spot along the Hourglass up-track @ 10080’ on a NE aspect.
• I noticed some localized blowing snow in the Yost- Glass Creek Col. The NW winds were rolling and bouncing the snow grains in the 10 cm above the snow surface.
• The snow surface below 9500′ on SE-S-SW sheltered areas was covered with tiny surface hoar and/or faceting snow grains