Avalancheur

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Avalancheur (even after the manufacturer (Etienne Lacroix Group) short Lacroix or Avalancheur Lacroix ) is the product name for a permanently established in one place gas-thrower ( pneumatic gun ) for the artificial triggering of avalanches by explosives .

description

An avalancheur is installed in the valley and, if necessary, the explosive charge is shot at the target with an explosive-filled bullet (arrow). The Avalancheur is before using injected and due to the previously defined objectives even without visual contact with the trigger point and operated in bad weather.

Launcher

The launching device consists of a rotatable lower part and a tube of 4 or 6 meters in length, which is used to launch the Avalancheur arrows. The arrow is loaded into the tube from behind and expelled by liquid nitrogen from a mobile 50-liter gas bottle at a pressure of up to 30 bar. The Avalancheur arrow describes a slight arc during flight. The range of the Avalancheur varies depending on the inclination of the pipe and, according to the manufacturer, can be up to two kilometers.

Avalancheur arrow

The Avalancheur arrow ( French : Flèche à neige ) with a length of about 1.8 meters and a diameter of about 40 mm contains about 2.2 kg of liquid explosive (SECUBEX), which loses its explosive power after a maximum of 48 hours (Failure problem not present for a long time). The explosive is distributed throughout the arrow and is only mixed and then poured in immediately before an arrow is used.

Secubex is a two-component explosive. The two components: Secubex S1 and Secubex S2 are individually non-explosive chemicals that only become an explosive mixture ( explosives ) when mixed . The chemicals are therefore not individually hazardous in terms of transport, storage and handling. Special custody is required for the detonator, e.g. B. in an explosives store approved for this purpose, required by national regulations.

The avalancheur arrow detonates the explosive charge on or under the snow cover and thus the possible detonation pressure of the explosive is not fully exhausted (ideal would be 0.5 to 3 meters above the snow cover). The percussion fuse is in the back of the arrow, by the tail unit .

Dimensions

  • Weight: 160 kg,
  • Dimensions without tube: 100 × 80 × 70 cm,
  • Dimensions of the base: 95 × 57 cm,
  • Pipe length: 4 or 6 meters,
  • Outer tube thickness: 83 mm,
  • Pressure per shot: 5 to 30 bar,
  • Shot angle: 45 ° (20 ° to 45 ° with special version).

Advantages and disadvantages of the system

Advantages of the system

  • Many small tear-off areas can be served and targets within a radius of up to 2 km can be set for blind shooting,
  • medium construction costs,
  • Independent of weather and time,
  • no personnel required in the target area (danger area),
  • very little interference with the environment is required.

Disadvantages of the system

  • Relatively high costs for the acquisition and per shot,
  • The explosive-laden arrow in the Avalancher and also in the military artillery is equipped with a percussion fuse, which means that the explosion does not usually take place above the snow cover, but below it and has the same disadvantages as shooting with military weapons,
  • the firing area must be free of people and buildings, as it cannot be ruled out that the firing range was incorrectly calculated or that the projectile does not fly to the planned target due to other circumstances (e.g. wind deflection),
  • the avalancheur arrow can be distracted significantly from the target in wind,
  • after the detonation, sharp-edged parts of the arrow may remain in the area and may have to be collected in spring,
  • there is an increased likelihood of failure at a shallow angle of incidence on the snowpack,
  • in the event of failure, explosives become inactive after 48 hours, but the detonator is still armed.

Operation of the device

The avalancheur is operated directly by a person on site. Access to the launch site must be safe from avalanches and provide an escape route. In Austria, the operation of the permanently installed system requires an explosive person with additional training in avalanche blasting . Training on the device is insufficient.

Detection

Whether the detonation and the success of the explosion occurred is recorded with a visual inspection and manual documentation in advance.

costs

The costs for an avalancheur are around 70,000 euros, each shot itself costs around 350 euros (excluding expenses for the operating team, barricade posts, etc.). Then there are the maintenance costs.

From 1982 to 2013, 135 Avalancheurs were sold (around 4 devices / year).

literature

  • Robert Bolognesi: Connaître et utiliser l'Avalancheur, Le vent des cimes éditions.

See also

Web links

Individual proof

  1. ↑ In the military sector, in which the Étienne Lacroix Group is also active, gas guns and pneumatic guns have not caught on.
  2. ↑ a b c d e f g Lukas Stoffel: Comparison of the blasting methods: Gazex, avalanche monitor / mast Inauen-Schätti, Wyssen Sprengmast, Avalancheur , comparison of methods of artificial avalanche release, WSL Institute for Snow and Avalanche Research SLF, January 24, 2013, p 14 f.
  3. ↑ Depending on the desired range: Everything under control , Montain Manager 3/2017, p. 63. With gas pressure against the danger of avalanches , Si (Sicherheit & Avalanche prevention), 2/2007, p. 94.
  4. ↑ A - Comment l'Homme étudie –t-il et prévient-il des risques d'avalanches? , Website: lvb.avalanche.free.fr.
  5. ↑ According to the manufacturer's website.
  6. ↑ PRO ANDES AVALANCHAS .
  7. ↑ Lukas Stoffel: Comparison of the blasting methods: Gazex, Avalanche Guard / Mast Inauen-Schätti, Wyssen Sprengmast, Avalancheur , Comparison of methods for artificial avalanche release, WSL Institute for Snow and Avalanche Research SLF, January 24, 2013, p. 2.