Item: Avalanche triggering by sound: myth and truth
Title: Avalanche triggering by sound: myth and truth
Proceedings: International Snow Science Workshop, Davos 2009, Proceedings
Authors: Benjamin Reuter and Jürg Schweizer WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland
Abstract: It remains a popular myth that avalanches can be triggered by noise. We will take a closer look and compare the impact of sound, the supersonic boom caused by low flying military aircrafts and explosives on the snow cover. Avalanche release by explosives is the method of choice for avalanche mitigation and for achieving infrastructure safety by avalanche control services. Explosions lead to high pressures and acceleration rates. Wave propagation is possible in three media: in air, within the snow cover and through the ground. Depending on the type of source, shock or pressure waves originate and propagate in air. Having reached the airfilled pores in the snow the latter may affect the ice matrix. The deformation caused is assumed to be proportional to the pressure amplitude of the wave at the surface. The pressure amplitudes caused by shouting or loud noise are at least about two orders of magnitude smaller (a few Pascal) than known efficient triggers. Triggering by sound can therefore be ruled out as a triggering option.
Keywords: snow avalanche, avalanche release, explosive control
Digital Abstract Not Available