Professional Observation

Observation Details

Signs of Unstable Snow

8900′ E,: cracking 2″ down over a melt-freeze crust extending 8 feet around the downhill edge of my skis. This happened once in 3400′ feet of ski touring. The defintion of isolated and a good example of spatial variability.

Key Points

Toured up from Mono Lake to look for 3/29 and 3/19 crust facet layers in the upper snowpack.

• Lundy Canyon was closed today for snow removal. Unsure when it will be ready for backcountry users.
• Below 9000′ soft surface snow was becoming moist as the day warmed.
• Below 9000′ there was only about 5 to 25cm of snow from 3/29. Underneath were facets, settled snow, wind crusts and melt forms depending on sun and wind exposure.
• At 9,500′ we dug on an E aspect. We found a thin MF crust, but no persitent grains at the 3/29 interface. We found rounding facets up to 1mm around the 3/19 interface, but no crust and were unable to identify that layer in stability test, or in shovel shears.
• ECTN in recent storm interfaces. Decomposing and fragmented preicp. particles (non persistent) at the test result interfaces.
• There is faceting going on in the upper 20cm of the snowpack below treeline. Cold clear nights are weakening layers just below the snow surface around crusts and thin wind slabs.