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| Titel |
Patterns of snow instability within a small basin |
| VerfasserIn |
Benjamin Reuter, Jürg Schweizer |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110632
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| Publikation (Nr.) |
 EGU/EGU2015-15016.pdf |
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| Zusammenfassung |
| The amount of horizontal variation seen among snow properties is anticipated to control the
avalanche release probability by either hindering extensive crack propagation or facilitating
localized failure initiation.
At a certain location and time snow instability is understood as the interaction of
snow mechanical properties. With a lately developed method mechanical properties
measured with the snow micro-penetrometer (SMP) including snow density, effective
modulus, strength and specific fracture energy are combined to model the failure
initiation and the crack propagation propensity. As this method offers fast enough data
acquisition we are for the first time able to cover a small 400Âm x 400Âm basin
with 150 objective measurements of the failure initiation and the crack propagation
propensity.
Field data from the Steintälli Basin above Davos collected during the winter seasons
between 2011 and 2013 contain different situations with respect to snow instability. We used
potential drivers of snow instability such as snow depth, elevation, aspect and slope
angle and selected the best fitting trend model of those drivers. The experimental
semi-variogram based on the residuals of the trend model was fitted to recover the range as
a measure of auto-correlation. By external drift kriging spatial predictions were
eventually computed to map the distribution of snow instability in the Steintälli basin.
Locations where we observed signs of instability during our field campaigns agreed
well with the interpolation results between SMP measurements. Moreover, our
results indicate that the distributions of both, the failure initiation and the crack
propagation propensity, influence basin scale snow instability. Our sets of drivers of snow
instability differed and could partly be explained by the meteorological conditions
prevailing during the accumulation period and the processes shaping the snowpack
afterwards. The range was in some cases related to the auto-correlation length of
the underlying terrain. Measuring spatial variations of snow instability is key to
understand the variable nature of avalanche formation related processes and is a
requirement to verify three dimensional snow cover model predictions in the near future. |
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