Item: On avalanche measurements at the norwegian full-scale test-site ryggfonn
Title: On avalanche measurements at the norwegian full-scale test-site ryggfonn
Proceedings: Proceedings of the 2006 International Snow Science Workshop, Telluride, Colorado
Authors: Peter Gauer, Karstein Lied, and Krister Kristensen, Norwegian Geotechnical Institute Sognsveien 72, NO-0806 Oslo, Norway, International Centre for Geohazards, c/o NGI
Abstract: Avalanche measurements and observations that were carried out at the Ryggfonn test site, Norway, on 16 April 2005 are analyzed. The data include pulsed Doppler radar measurements, impact pressure readings fromload cells mounted at two locations within the track and stress readings from load plates flush with the upstream slope of a catching dam. The radar measurements were used to derive velocities and estimates on the retarding acceleration. The retarding accelerations show a wide discrepancy with commonly used model assumptions. Pressure measurements were combined with velocity measurements. The measurements infer that commonly used drag factors are not sufficient to describe force exert by slow moving wet snow. Measurements with load plates imply plastic failure rather then Coulomb-type friction. Field observation of the avalanche track suggest that erosion / abrasion due to (saltating) particles is one possible entrainment mechanism.
Keywords: avalanche, full-scale measurements, velocity, acceleration, impact pressure, shear stress
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