Eastern Sierra Avalanche Forecast - 1/14/15

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THIS AVALANCHE ADVISORY EXPIRED ON January 15, 2015 @ 7:15 am
Avalanche Advisory published on January 14, 2015 @ 7:15 am
Issued by Sue Burak - Inyo National Forest
advisory discussion

A thin dusting of new snow Tuesday morning provided a softer skiing surface than last week’s icy traces and crusts. The rounding facets and clusters of rounded forms I saw a week ago when daytime highs were in the upper 50’s decided they would go with flow and revert back to faceted forms. Increasing temperature gradients in place since the latest cooling trend began on Friday means more vapor is moving from the warmer parts of the shallow snowpack near the ground towards colder layers near the surface. What I am seeing over time is that facets are not increasing in size. This is probably due to the fact that snow densities are higher than last year- higher density snow means pore spaces are small and there isn’t a lot of space for facets to grow. But the important fact is that the current snowpack has low strength, including the snow under the hard slab in alpine areas. The winter roller coaster continues and let’s winter kicks into gear soon. There have been storms, many more than last year but moisture has been limited, resulting in inches of new snowfall instead of footage.

recent observations

 Observations made yesterday in the Red Cone area and in the Crystal Lake trees show a thick layer of facets with some solid striated grains is present on the lower north facing slopes in the Red Cone Bowl. Total snow depth was 70 cm. The thin crumbly sun crusts found in lower elevations were not present in the snowpack.  Higher in the bowl, snow was more shallow as a result of the early January wind event. North winds had stripped the top and both breakable and firm slabs capped small faceted grains.  The snow temperature profile suggests conditions are favorable for faceting to continue as clear, cool winter days and clear cold nights dominate the weather for the week. Despite a snowpack composed entirely of faceted crystals, tests for instability did not produce any results- nada.

A report from the Hammil Bowl area revealed the hard wind slabs formed during the early January northeast wind event supports boot packing. There were so many rocks, skiing and riding conditions were reported as not being good at all.

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