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
Figure 1 The different Gazex® effects
It is important to note that Gazex® does not release only by shock wave. The following
effects can be noted (Chernouss and others, 2006): If the snow mantle is not unstable enough
to start the release of the avalanche by shock wave, then the Gazex® causes triggering
through a direct downhill push on the snow mantle (release is pear shaped). Then, if the
instability increases, but not enough to release only by shock wave, it can be observed that the
direct push projected on the central part of the slide path also causes a release in the adjacent
areas of the slide path, by transmission and shock wave combined. Releases by shock wave
are efficient mainly during the snow fall or just after, because it is when the snow mass to be
lifted is the lightest; the density of snow is low and there is more air in the snow mantle. Later
the snow becomes more dense and transforms itself structurally.
An important evolution allowed to replace the anchoring rods by a counterweight system
when the slope, where the exploder is to be installed, does not have sufficient stability. This
inertial system is more and more used.
Figure 2 Classic and inertial Gazex® systems (respective volumes of 4.5 and 0.8 m 3 )
The control software is now designed to download the following recorded data:
122 The Gazex® avalanche release system