International Symposium on Mitigative Measures against Snow ...

<strong>International</strong> <strong>Symposium</strong> on Mitigative Measures against Snow Avalanches
Egilsstaðir, Iceland, March 11–14, 2008
CONCLUSIONS AND OUTLOOK
From the measurements of the forces applied to the snow nets and the determination of the
temporal and spatial variable snow cover in the test field “Hafelekar” several interesting
conclusions can be drawn:
• The major part of the snow load is applied to the posts.
• During the observation winter 2006/07 both the tension forces in the anchors and
wire ropes and the pressure forces in the posts, determined according to the theory
of Haefeli, are overestimated.
• The terrestrial laser scanner is a very useful instrument to detect the snow depth
distribution with a high spatial resolution, however the time needed for image
acquiring is rather long; the best results can be obtained under an overcast sky, at
dawn or at night.
So far field data was required in a relatively snowless winter 2006/07. Additionally, the snow
cover distribution in the test field was very heterogeneous. Thus, a comparison between the
effectiveness of the two equipped snow net systems is not yet possible, but will be one of the
future project goals.
REFERENCES
Boutillier, B., F. Nicot, J. Meyssonnier, O. Gagliardini and F. Darve. 2004. Interaction
between a snowpack and a snow net system. In Daily Publication of the <strong>International</strong>
congress Interpraevent, Riva del Garda, Trento, 2004, 59−70.
BUWAL/WSL. 1990. Richtlinien für den Lawinenverbau im Anbruchgebiet. Bern.
Haefeli, R. 1954. Vorschläge zur Konstruktion und Berechnung von Netzwerken. Davos,
Eidgenössisches Institut für Schnee- und Lawinenforschung, Externer Bericht Nr. 2112.
Margreth, S. 1995. Snow pressure measurements on snow net systems. In Proceedings of the
ANENA <strong>Symposium</strong> Chamonix, May 30 – June 03 (1995), 241−248.
Margreth, S. and A. Roth. 2006. Interaction of flexible rockfall barriers with avalanches and
snow pressure. In Proceedings of the <strong>International</strong> Snow Science Workshop, Telluride,
Colorado, October 1-6 (2006), 691-700.
Nicot, F., M. Gay and J.M. Tacnet. 2002. Interaction between a snow mantel and a flexible
structure: a new method to design avalanche nets. Cold Regions Science and
Technology, 34, 67−84.
Wiatr, T. 2007. Multitemporale Schneedeckenbeobachtung mittels terrestrischen Laserscanning
im Untersuchungsgebiet Hafelekar, für weiterführende Berechnungen der
Belastungssituationen von Schneenetzen in geeigneten Simulationsmodellen. Jena,
Friedrich-Schiller-Universität, Diplomarbeit.
Rainer, Rammer and Wiatr 47