Avalanche whistle

Explosive charge ready-made for ejection

Open propellant charge cup with black powder and electric bridge detonator

An avalanche whistle (also brand name: Booster 250 or Mörser 5400) is a mobile or stationary single throwing system for explosives to trigger an avalanche . The charge of an avalanche whistle can be ejected up to 250 meters (according to some manufacturer information up to 400 meters). In practice, a throw of about 150 to 200 meters is realistic.

function

The launching system consists of a tube and directly takes an explosive cartridge (e.g. SYTAMIT 1). This is ejected from the tube by a black powder propellant ( pyrotechnic ). When it is ejected from the tube, two detonators are pulled and the safety cord attached to them is ignited (redundant ignition). With the amount of discharge charge, the inclination of the barrel, this in relation to the weight of the explosive cartridge, the throwing distance is varied. The throwing distance is a maximum of 250 meters for an explosive cartridge of 2.5 kg. In Austria , the avalanche whistle is loaded with explosive cartridges up to 2.5 or 5.0 kg in Switzerland up to 2.7 or 5.4 kg per pipe. A stationary pipe installed avalanche is to previously predetermined goals (demolition zones of avalanches ) injected (set) and can therefore be operated without visual contact and in bad weather. The mobile avalanche whistle can only be operated if there is visual contact with the target point, and there must also be safe access to the place of use and an escape route. The charges of the avalanche whistle ignite on the snow cover. For the trigger point height, explosives and the amount of explosives as well as the ignition of the explosives, see: Avalanche triggering by explosives and artificial avalanche triggering .

RECCO strips

The components of a charge used in addition to the explosives to launch from the avalanche whistle consist almost entirely of rotable material, such as. B. wood. Each load is equipped with a RECCO strip to make it easier to find failures, as a failure ( dud ) could slip on the snow cover. As with manual avalanche blasting, this is a disadvantage of this system, as it would be optimal if the explosive charge detonated 0.5 to 3 meters above the snow cover in order to fully exploit the detonation pressure.

Mobile systems can be set up on snow groomers , snowmobiles , sledges and road vehicles of all kinds. Several pipes, as they are used in a similar way with the avalanche whistle, combined are called avalanche monitors , and such launching systems are operated stationary on masts.

In Austria and Switzerland, the operation of the system requires special additional training for those authorized to blast . Just initial schooling is insufficient. The propellant is ignited electrically ( blasting machine ) on site by the person authorized to blast .

costs

The costs for an avalanche guard are around 12,000 euros per mobile launch tube, each shot itself costs around 60 euros (excluding expenses for the operating team, barrier posts, etc.).

Authority to issue orders and liability

The order for the use of explosives to trigger an avalanche for a specific area is usually made by the avalanche commission or a similar institution. A person authorized to blast is generally not authorized to carry out avalanche explosions. With regard to the execution of the blasting work itself, however, the person authorized to blast alone is responsible and authorized to issue orders. He determines how and by whom the explosives and detonators are transported, how much explosives are used, from where the corresponding charge is detonated, how the locking and safety measures are to be implemented, who will accompany him and who will detonate the explosive charge Etc.

Detection

With mobile systems, a visual inspection and manual documentation records in advance whether the detonation and the success of the explosion occurred.

See also

• List of avalanche accidents , list of avalanches and landslides, landslides and list of disasters
• Search for avalanche victims , avalanche shovel and avalanche cord

Individual proof

1. ^ Name of the company Inauen-Schätti AG.
2. ↑ ^{a b} Lukas Stoffel: Comparison of the blasting methods: Gazex, avalanche whistle / 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. 10.