Item: Comparing two methods of artificial avalanche triggering: gas vs. solid explosives
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Title: Comparing two methods of artificial avalanche triggering: gas vs. solid explosives
Proceedings: International Snow Science Workshop Proceedings 2018, Innsbruck, Austria
Authors:
- Stephan Simioni [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
- Jürg Schweizer [ WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland ]
Date: 2018-10-07
Abstract: Remote avalanche control systems (RACS) are increasingly employed to protect transportation routes. The surcharge on the snowpack, which may lead to failure and subsequently to an avalanche, is caused by an explosion, often by igniting a gas mixture or solid explosives. With both types of explosions avalanches can efficiently be triggered - as numerous systems are successfully operated around the world. However, it is not clear how much the two methods differ with regard to their impact on the snowpack - apart from the obvious fact that the tube-like systems used for gas explosions cause a directed impact. We performed side-by-side experiments on a flat field with a prototype gas exploder and solid explosives. By testing both methods on the same day at the same location we tried to avoid the influence of snow properties on the impact characteristics. Our results show that differences in the air pressure above the snow surface as well as the accelerations within the snowpack are relatively small between the two types of explosions for a similar energy density - at least in the direction of the gas exploder axis. Both quantities strongly decay with increasing distance from the point of explosion. At large distances, say 100 m, the impact is small with both methods and the additional load caused on the snowpack seems insufficient in most cases to trigger an avalanche. Hence, we confirm that both types of explosions are efficient, but avalanche triggering seems rather be caused by initiating a crack close to the system where the impact is large, with subsequent crack propagation across the slope.
Object ID: ISSW2018_P02.8.pdf
Language of Article: English
Presenter(s):
Keywords: snow cover, snow avalanche control, artificial triggering, explosion, air pressure wave.
Page Number(s): 158-161
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