Item: Observations of Two Seasons of Sintering in a Mountain Snowpack
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Title: Observations of Two Seasons of Sintering in a Mountain Snowpack
Proceedings: International Snow Science Workshop, Davos 2009, Proceedings
Authors:
- Edward H. Bair [ Bren School of Environmental Science & Management, University of California, Santa Barbara CA U.S.A. ]
- Jeff Dozier [ Bren School of Environmental Science & Management, University of California, Santa Barbara CA U.S.A. ]
- Robert E. Davis [ US Army Cold Regions Research and Engineering Laboratory, Hanover NH U.S.A. ]
- Thomas U. Kaempfer [ US Army Cold Regions Research and Engineering Laboratory, Hanover NH U.S.A. ]
- Michael T. Colee [ Bren School of Environmental Science & Management, University of California, Santa Barbara CA U.S.A. ]
- Randall Mielke [ Bren School of Environmental Science & Management, University of California, Santa Barbara CA U.S.A. ]
- Jane R. Blackford [ Centre for Materials Science and Engineering , University of Edinburgh, Scotland ]
Date: 2009
Abstract: We present results from an ongoing two-year study at Mammoth Mountain, California. We track multiple layers, starting at a variety of initial conditions and subjected to different temperature gradients, from deposition to melt at two different sites. We examine samples with optical microscopy under cross-polarized light, with low-temperature scanning electron microscopy, and with an x-ray spectrometer. The neck ratio (bond diameter to grain radius) quickly approaches a value of 0.5-0.6. Density increases linearly throughout the season with grain diameter, but inter-grain distance, measured from grain centre to grain centre, also increases. An explanation for this counterintuitive behaviour is that coarsening is the rate-limiting step. Densification, caused by sintering, is re-initiated by coarsening. We observe impurities typical of Sierra snow with no difference in spatial distribution, measured 6 times in a season. As a case study, we examine sintering changes in a weak layer that was responsible for destructive avalanches in December 2008, including one that severely injured a Mammoth patroller.
Object ID: issw-2009-0115-0119.pdf
Language of Article: English
Presenter(s): Unknown
Keywords: sintering, avalanche, microscopy
Page Number(s): 115-119
Subjects: two seasons sintering mountain snowpack
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