Professional Observation

Observation Details

Signs of Unstable Snow

Key Points

I toured around Panorama Dome and then the Sherwin Ridge to get a sense of snow surfaces, the upper snowpack, and any wind slab or loose dry avalanche problems before it starts snowing again tonight.

• I saw several avalanches from the past 48 hours on the Sherwins and Mammoth Crest. The most recent was a wind slab that released just below the Sherwin Ridge near The Hose yesterday, 1/17. I stomped above the crown, the hangfire did not release. I did a quick crown profile and my extended column test did not propagate. (See avalanche observations for more details)
• Lots of stomping around ridges like a petulant child, and kicking cornices like an awkward avalanche ninja confirmed that wind slabs have become stubborn. I could get them to crack if I stomped above the skin track.
• The snowpack in the area had settled and been wind-stiffened. It was too dense to sluff. On the surface in shady and sheltered areas near and below treeline there’s a thin layer of soft, low-density mix grains. I found decomposing-fragmented precipitation particles in there, but also 2-3mm surface hoar crystals and small near-surface facets. I dug several test pits in wind-loaded and sheltered areas and found some wind interfaces highlighted in my tests, but no propagation and no buried weak layers. The snowpack is deep! In most places it was at least 3 meters.
• Windward fetchs and solar aspects had wind board or sun crusts. North winds seem to have been light; most wind-affected snow was on typically leeward slopes (northwest, north, east, and southeast).
• Tree wells are deep! Use caution if you find deep, loose snow.