HR: 17:30h
AN: H44A-07    [Abstracts]
TI: Powder Snow Avalanches - Results From Vall\'ee de la Sionne, Winter 2004
AU: * Turnbull, B
EM: turnbull@slf.ch
AF: Swiss Federal Institute for Snow and Avalanche Research, Fl\"uelastrasse 11, Davos Dorf, CH - 7260 Switzerland
AU: McElwaine, J
EM: j.n.mcelwaine@damtp.cam.ac.uk
AF: Dept. Applied Mathematics and Theoretical Physics, Cambridge University., Centre for Mathematical Sciences, Wilberforce Road,, Cambridge, CB3 0WA United Kingdom
AU: Bartelt, P
EM: bartelt@slf.ch
AF: Swiss Federal Institute for Snow and Avalanche Research, Fl\"uelastrasse 11, Davos Dorf, CH - 7260 Switzerland
AB: Powder snow avalanche surfaces can be effectively tracked using videogrammetry. 3-dimensional surface maps were generated from two digital video recordings of an artificially released avalanche, captured from different places. From these maps the avalanche volume and front velocity is inferred. Several different types of sensor are mounted on a mast in the avalanche path. These include impact pressure sensors, optical velocity sensors and a pitot air pressure sensor. In this paper the air pressure data and the information it gives about the air flow both outside and inside the avalanche is described in detail. A simple dipole approximation is used to estimate the speed and size of the avalanche and a comparison with the videogrammetric analysis can be made. In addition the internal structure of the avalanche is considered and its implications for modelling discussed.
DE: 1899 General or miscellaneous
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting