Wyssen Avalanche Tower LS12-5 and LS24-5
Numbers of the winter season 2022/2023
Set up and function
The Wyssen avalanche tower is designed to trigger avalanches proactively with remote-controlled blasting. To trigger an avalanche, a coded command is sent from the control center WAC.3® to the control system of the deployment box to initiate blasting. The deployment box contains either up to 12 explosive charges or 12 Wyssen 2K® charges for the LS12-5 and up to 24 Wyssen Wyssen 2K® charges, which can be individually deployed by remote control. When the explosive charge is dropped two igniters are pulled, and the explosion is set off after a time delay. The charge hangs from a cord about 2-3 meters (7-10 ft) above the snow cover, and the cord is dropped after blasting. To reload explosive charges the deployment box is lifted from the tower by helicopter and brought to a workshop or warehouse.
LS12-5
LS24-5
Deployment box
Solar panels are installed at the deployment box as well as the antenna. The dropping mechanism, the electronics, and 12 or 24 prepared explosive charges are on the inside of the box, protected from the elements. Thanks to the smart concept highest reliability is guaranteed.
LS12-5
LS24-5
Deployment box with dimensions
View of deployment box
LS12-5
LS24-5
Charge 07
The explosive charge consists of two orange half-shells with pre-mounted percussion igniters, which are assembled with 4-5kg (9-11 lbs) of explosives. The charge containers are assembled by the operator on site. Wyssen sells the charge containers and retaining cord (6.5m / 21 ft). Explosives and other pyrotechnical elements are purchased directly by customers from the appropriate suppliers.
Use only with LS12-5 and LS6-5.
Wyssen 2K® Charge
Effectiveness
Practitioners have found that the greatest degree of success for controlled release of avalanches is achieved by a remote-controlled detonation of an effective explosive at the right time and in the right place.
From the avalanche operator’s point of view, a blasting installation must be extremely reliable and effective as well as simple to operate and maintain. The installation in the terrain must be straightforward and the interference of the installation must have minimal impact on sensitive mountain environments. Wyssen avalanche towers are ideal for fulfilling these requirements.
Smallest residual risk thanks to the largest effective range
- Blasting above the snow with bigger charges (4-5kg /9-11lbs) gives the maximum effective range up to 260m in diameter (850 ft)
- Explosives with high detonation speeds produce N-shaped pressure waves which have been proven to cause the best release effect, particularly at a greater distance from the detonation point
- Positioning a tower on a prominent terrain feature and including a 12m (39 ft) tower instead of 10m (33 ft) enables the effect to be reached in locations of pressure shadow (in couloirs, behind terrain ribs)
- Releasing smaller quantities of snow in increments, decreasing possibility for larger avalanches
- Very good stability test for assessment of the local avalanche danger
Highest cost-effectiveness
- Low investment and operating cost in comparison with permanent protective measures (snow sheds, bridges, tunnels)
- Lowest operational costs thanks to its ingenious system concept
- Damage to infrastructure is avoided by the release of smaller portions
- Economic benefits thanks to reduced closure times
Highest reliability
- No critical or moving parts are exposed to the weather
- Solar power supply or wind generator avoids the necessity of vulnerable supply lines in the terrain
- Annual maintenance ensures maximum reliability
Highest degree of safety for the operating staff
- Preparation of the charges takes place in protected areas
- No staff in the danger area thanks to remote-controlled release
Reduced closure times thanks to rapid release, around the clock and in all weathers
- Remote-controlled installations allow operation around the clock
- Very rapid operation possible
- Short closure times
- Less time snow plowing as avalanches are released in smaller portions
Environmental stewardship
- Foundation Footprint is only 1m2
- Short construction times in the terrain simplify planning and implementation
- Blasting over the ground prevents damage to the vegetation cover
- Dismantling after operating life possible without any problems
Functional principle Avalanche Tower
Avalanche Tower Avalanche Tower Avalanche Tower Avalanche Tower Avalanche Tower Avalanche Tower
Technical data
| GENERAL | LS12-5 | LS24-5 |
|---|---|---|
| Weight deployment box incl. charges | 530 kg (1169 lbs) | 540 kg (1190 lbs) |
| Dimensions deployment box (l x b x h) | 1600 x 1050 x 1200 mm (5 ft 2 in x 3 ft 5 in x 3 ft 11 in) | 1830 x 1360 x 1300 mm (6 ft x 4 ft 6 in x 4 ft 4 in) |
| Dimensions of tower (h) | 10 m / 12 m | |
| Inclination of tower | 15° in direction of slope towards the valley | |
| Loading capacity | ||
| Number of charges per launcher up to | 12 pcs | 24 pcs |
| Amount of explosives per charge | max. 5 kg (11 lbs) | 4.2 kg |
| Mechanism in the deployment box | ||
| Drive unit | DC Motor | |
| Time for rotating one position | approx. 13 s | approx. 16 s |
| Power Supply | ||
| Battery in deployment box supplied by solar panel | 12 V | |
All in one online platform
The latest software generation includes new hardware for operating, monitoring and data storage of the well-proven Wyssen Avalanche Towers, detection systems and weather stations.
Video about operational avalanche control with WAC.3®:
Advantages
- Intuitive web-based operating interface
- Operable from any web-enabled device (Computer, Tablet, Notebook, Smartphone)
- Operation independent of location
- Multiple release from Avalanche Towers possible
- Monitoring of systems 24/7
- Automatic documentation and archiving of activites and system data
- Data transfer via mobile network, radio connection or satellite
Extensive additional features
- ExploDoc
- RiskEval
- ComTool
- HeliTrack
- Weather stations
- 3D snow height measurement via LIA® etc.
NEW: WAC.3® Cockpit
The integration of all technolgies, systems and information in one single platform.
Transportation by Helicopter
The deployment box is transported by helicopter to the towers in the terrain. Thanks to the guiding system the pilot is able to perform the placement on the tower on their own without a flight assistant. The deployment box orientates itself automatically into the correct position. A safety switch detects the correct position, after which the system becomes operational. The operation can verify the placement of the deployment box on the correct tower with the GPS receiver. The system will not be activated if placement is incorrect. When all charges are used or at the end of the season, the deployment box is retrieved from the tower for reloading or to be stored in a safe location for the summer. Thanks to the special Wyssen heli hook, the pilot can also perform this maneuver without a flight assistant.
Safety regulations
Personnel
In order to load and operate Wyssen systems, personnel must have attended a certified course by the company and possess a valid certificate for the artificial release of avalanches with explosives. Furthermore, it is very important that the operating staff have the corresponding training and experience for risk assessment, planning of measures, implementation of measures as well being able to assess secondary avalanches and avalanches that could be larger than expected.
Flight routes
The helicopter routes taken by which avalanche tower deployment boxes are transported must be so chosen that from the loading place to the avalanche tower a distance of at least 500m is maintained at all times and in all directions away from any persons not involved in the operation. Flying directly over populated areas, open roads as well as people, technical installations (e.g. mountain cableways, mountain restaurants and relay stations) and open ski slopes is prohibited.
Transport
The helicopter company must have an authorisation in order to carry loaded deployment boxes. Depending on the country, the intended flight routes with loaded deployment boxes must be approved by the flight authorities.
Storage
Approval for storing explosives: for each tower location authorisation must be requested by the customer from the responsible authorities for storing explosives in the avalanche tower deployment boxes during the period of operation.
Basic Principles of Controlled Avalanche Release
It is known from practical experience and from the theory of how avalanches arise in deep winter, that the effect of a detonation above the snow cover leads to the best results with respect to residual risk of unpredictable avalanches. The explosive devices used should give a high detonation speed and produce a large volume of gas with a high work factor. Tests with numerous experiments show that explosives with the above-mentioned properties and charging positions above the snow cover give the highest effective ranges. The following table from the WSL Institute for Snow and Avalanche Research SLF Davos Report no. 53/1996 shows the approximate effective ranges for dry new snow of various explosive charge sizes in different positions with respect to the snow surface.
In order to test and to safeguard the avalanche release zone, the whole of the potential release area must be subjected to an additional stress (e.g. by a detonation). This is necessary, because the location of the so-called „hotspots“ (super weaknesses) are not known in advance. An acceptable residual risk after blasting operations is only then reached if these „hotspots“ have been subjected to a sufficiently high additional stress and high strain rates within the snow cover with high speed of deformation (= high detonation speed).
| Height of Detonation Point | Charge Size | Radius of effective range to prevent a natural release | Radius of effective range to prevent a release by a single skier |
|---|---|---|---|
| Blasting above the snow (+3 - 3.5 m) | 4 - 5 kg | 120 - 130 m | 70 m |
| Blasting above the snow (+2 - 2.5 m) | 1.5 - 2.5 kg | 80 - 90 m | 50 m |
| Blasting above the snow (approx. +1 m) | 4 - 5 kg | 80 - 90 m | 50 m |
| Blasting above the snow (approx. +1 m) | 1.5 - 2.5 kg | 60 - 70 m | 35 - 40 m |
| Surface blasting | 4 - 5 kg | 50 - 60 m | 30 - 35 m |
| Surface blasting | 1.5 - 2.5 kg | 35 - 40 m | 20 - 25 m |
| Blasting in snow (approx. -0.2 m) | 4 - 5 kg | 40 m | 25 m |
| Blasting in snow (approx. -0.2 m) | 1.5 - 2.5 kg | 25 m | 15 m |
| Blasting in snow (-0.7 m) | 1.5 - 5 kg | 10 m | 5 - 10 m |
| Mortar 12 cm (0 m) | 3 kg | 40 m | – |
| RPG 8.3 cm (0 m) | 0.7 kg | 20 - 25 m | 10 - 15 m |
| Mortar 8.1 cm (0 m) | 0.6 kg | 15 - 20 m | 10 m |
Source of the table: SLF Davos Report No. 53/1996
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