Slope preparation
Slope preparation refers to the mechanical compaction of snow to form a ski slope for general skiing such as. As skiing, snowboarding , cross-country skiing , fun sport or competitive sports . In connection with skiing, slope preparation with mechanical equipment is a relatively new process that did not emerge on a large scale until the 1960s.
history
The slope preparation began with the development of skiing into a mass sport and the widespread construction of lifts. Prior to this, slopes were mainly prepared for sporting events and by clubs for an incident with the skis ( rippling ). In the 1950s, roller rollers ( piste rollers ) were used occasionally , which were steered by one skier in front or two skiers - front and rear.
Special snowmobiles and snowmobiles were produced before the Second World War (e.g. Bombardier , 1927), but were not primarily used for slope preparation. In 1962, the Prinoth company produced the first prototype of a snowcat for slope preparation, the P 60, and two years later the first series vehicle (P 15). In the past, resourceful inventors had equipped agricultural machinery with caterpillars and tried to use them to prepare slopes. In 1968 the first snowcat from today's world market leader, the Kässbohrer company, followed .
The previously used hand rollers were first attached to the snow groomers in different versions until the milling machines, smoothing boards (finishers) and shakers (vibrators) still used today came into use. Front clearing shields were also added, later also snow blowers and front renovators. The smoothing boards (finishers) were the first to create the typical longitudinal grooves that are still known today when preparing slopes.
The preparation of snowboard fun parks has also been done by machine around the 2000s and can now be found in every major ski area.
Tasks, goals and influences
The slope preparation is based on the ideas and wishes of winter sports enthusiasts and their skiing style. Most winter sports enthusiasts prefer a homogeneous slope with as little damage or icing as possible or surprises such as waves, bank slopes, holes or accumulations of soft snow.
Main tasks of slope maintenance
The main task of slope preparation is to press in new snow, mix it with the underlying old snow and create a stable layer. In the case of an existing old snow slope, however, the slope damage caused by the influence of the weather and skiers is compensated (e.g. removal of snow, milling of layers of ice, etc.) and an optimal distribution of the snow on the slope is sought.
For a good and permanent slope preparation, the slope groomer must
- on the right deployment time,
- the speed of the snowcat,
- the correct milling speed,
- the milling depth, as well as
- the rest time (approx. eight hours) for the binding and solidification of the snow (called the sintering process)
be respected. Basically, the deeper the snow cover is worked up, the more durable the slope surface that is generated.
During the slope preparation, the snow crystals are compressed, air escapes from the prepared area and the density of the snow cover increases as a result. The compaction of the snowpack also increases the resistance to heat penetration.
The slope preparation protects the underlying vegetation from the steel edges of the skis , at the same time it is ensured that the surfaces of the skis and snowboards are protected from contact with stones and soil. The level, uniform preparation of slopes also ensures more safety for the athletes, since bumps, waves, holes and grooves are eliminated. This will reduce the risk of injury.
Optimal times for slope preparation
The slopes are usually prepared outside of the operating hours of the conveyor systems for safety reasons. The snow also needs about 8 hours to bind and solidify. For these reasons, many slope operators prohibit entering and driving on the slopes when the conveyor systems are closed. When using the winches on snow groomers in the piste area, there may also be a mortal danger to potential skiers / tourers due to the winch rope, in particular due to a surprising collision with the rope.
Trail preparation
Cross-country ski runs are groomed in accordance with the operator's instructions and should also be done in the evening or at night. When the cross-country ski run is being prepared, a cross-country ski track device is pulled behind the snow groomer. The snow is loosened beforehand by a tiller and then compacted again by the cross-country ski tracker. For the classic style, ruts are pressed into the snow to guide the cross-country skis. With the skating technique, however, a wide strip of snow is created.
Slope preparation for competitive sports
Ski racers and competitive athletes prefer to ski on smooth and non-slip, sometimes even on icy or icy slopes. Such an icy or icy slope also increases the equality of opportunities for racers, as it offers the same conditions for racers during a competition for longer .
To freeze a racing slope, a bar (pipe with holes) is used to inject water at high pressure into the snow cover to a depth of around 30 to 40 cm. The surface then has to be roughened in good time to make the ice more mobile. Such a slope can be difficult to master for untrained winter sports enthusiasts.
Chemical slope preparation
Chemical agents can significantly increase the durability of groomed slopes. In different countries or in certain areas (e.g. glaciers ) such methods are completely prohibited for this purpose. Some ski resorts of their own accord prohibit the use of such agents. These are basically fertilizers like those used in agriculture (e.g. sodium, calcium, potassium and ammonium compounds). This solidifies the snow cover for approx. 24 hours - even at temperatures above 0 ° C - and is still passable. The fertilizers remove moisture from the snow cover and thus energy, and the snow cover can cool down on the surface and freeze more easily. Solidifying agents are also called snow cement .
Characteristic longitudinal grooves
During slope preparation, the snow layers mixed by the snowcat with the front clearing blade, front snow blower, the tracks of the caterpillar and the rear tiller or the compacted new snow are leveled with the smoothing board (finisher). A steel strip or back-up made of plastic or rubber material is attached to the smoothing board, which creates the characteristic shapes of the longitudinal grooves (cord structure) when driving over the compacted snow. According to the direction of travel of the piste machines, the grooves run roughly in the direction of the fall line or in the direction of the slope. The groove spacing (wavelength of the profile contour) is equal to or less than half the width of typical downhill skis for adults. When traveling along the grooves, they are therefore carried by at least two ridges between the grooves. When driving at other angles, it is easier for ski edges to cut into the ridges than in a completely flat snow surface and thus find a better grip. Turns and crossings are therefore possible with less use of the edges, and the slope appears more grippy despite the superficial compaction.
The longitudinal grooves also create a larger surface area of the snow cover so that the ambient cold can cool the snow better (supports the sintering process).
costs
The preparation of ski slopes is associated with considerable costs for companies. The snow groomer drivers usually work in the evening and at night. A modern snowcat costs around 300,000 to 400,000 euros. Each snow groomer has a working width of four to seven meters. Maximum driving speed about 20 km / h. Snow groomers use around 25 to 30 liters of diesel per hour and, depending on the ski area, run around 200 to 1000 operating hours per season.
Slope preparation and snow management
In terms of a comprehensive, sustainable, resource-saving and environmentally-oriented corporate policy, some slope operators are trying to optimize slope preparation and snow management. This is very often a cost factor (e.g. with regard to mechanical snowmaking ).
For this purpose, z. B. Attention is paid to an optimal slope design ( topography ) and slope construction, extensive greening and summer management. The automatic snow depth measurement can also show the snowcat driver where there are natural snow deposits that can be moved to other places where the snow cover is thin so that there is an evenly distributed, compact layer of snow on the slopes.
environmental Protection
Slope preparation in times of climate change
Studies show an increasing shortening of the snow season due to global warming . There is a clear trend towards warming and a decrease in the amount of snow in many winter sports regions. Both the use of artificial snow and slope preparation are among the strategies for adapting to the effects of this climate change. Hardly any winter sports resort in the Alps can do without artificial snow . Operators of winter sports facilities are adapting to climate change, decreasing cold periods and an increase in the production of artificial snow. With the help of technical snow care, preparatory work can be done in order to use technical snowmaking more efficiently. Piste preparation can reduce the minimum snow depth required for skiing by 10–20 cm and thus increase the possibility of maintaining skiing despite the reduced amount of snow. An OECD study, however, assumes that if the ambient temperature continues to rise above a certain limit value, neither artificial snow production nor slope preparation in the Alps will be a viable solution in the long term and winter sports in the Alps will hardly be possible in the long term . The long-term continuation of ski operations therefore depends on the achievement of the 1.5-degree and two-degree targets agreed in the Paris Agreement . It should be noted that the slope preparation itself contributes to the emission of greenhouse gases due to its enormous energy requirements.
Mechanical damage from slope preparation
The preparation of ski slopes can cause mechanical damage to the ground vegetation. If the snow cover is too low, z. B. by the caterpillars and clearing blades of the snow groomers - especially on the edges of terrain and bumps - the vegetation can be sheared off. Likewise for tight turning maneuvers.
Due to the large contact area of snow groomers, their total weight (5 to around 12 tons) is usually of no relevance, as the wide caterpillars mean that the pressure on the ground is lower during normal operation than with a pedestrian.
Biological damage caused by slope preparation
The compression of the snow cover can impair the air supply for the plant communities below. In spring, the snow may be delayed in melting. This in turn can have an impact on the composition of the plant communities. B. can react very sensitively to external influences in high alpine regions.
Operating materials for snow groomers
The operational loss of hydraulic oil, engine oil and fuel from snow groomers is usually spread over a very large area. In the event of damage, z. B. If a hydraulic line breaks, relevant environmental damage can also occur at one point in the ski area. Operators try to use biodegradable oils to keep the environmental damage within limits. With the introduction of diesel-electric drives instead of diesel-hydraulic drives for snow groomers, the environmental impact in the event of damage from leaking hydraulic oil can be further reduced.
The advantage of diesel-electric drives is that the diesel engine usually works in the optimal speed range, the electrical power transmission has a significantly better efficiency than the hydraulic one, and operating costs can thus be further reduced.
Exhaust gases from the engines of snow groomers
The emission of exhaust gases from diesel engines in snow groomers for snow grooming has decreased significantly in recent years. For example, the Prinoth company has reduced nitrogen oxide emissions by 50% with the new Leitwolf model and 90% fewer fine dust particles are emitted (emissions standard: Euromot IIIb in the EU and Tier 4i in North America ). This with a simultaneous reduction in fuel consumption.
The first fully electric snow groomers (snow groomers, snowmobiles) are already in series production.
Individual evidence
- ↑ See e.g. B. the story of the Oberwald ski lift - that's how it all began .
- ↑ Here is the story of the heavy equipment , Trisanna ski area.
- ^ A b Carolin Lang: From tractor to high-tech beast , Schladming-Dachstein Tourismusmarketing GmbH, November 28, 2017.
- ↑ Piste preparation , website: Ischgl.com.
- ^ Anton Lafenthaler: Documentation. Gasteinertal - ski tours - ski slopes 1920 - 1980 , Gastein in the picture from June 18, 2015.
- ↑ Prinoth history - over 50 years of experience , website of the Prinoth company, South Tyrol.
- ↑ History of the snowcat on pistenraupen.de
- ↑ Prinoth: Does a beautiful slope also mean that the quality of the slopes will last? , Website: Seilbahn.net.
- ↑ Slope preparation - What is a good snow sports slope? .
- ↑ a b c Intelligent milling machine - cleverly used , Kässbohrer website.
- ↑ In 1983, the Kässbohrer company brought the first winch for snow groomers for slope preparation onto the market and these have now become established. KÄSSBOHRER GELÄNDEFAHRZEUG AG: Who invented it? .
- ↑ Peter Gaide: Kässbohrer and Prinoth - Der Zweikampf , Brand eins magazine, 2013.
- ↑ Slope preparation - What is a good snow sports slope? .
- ↑ The automatic snow depth measurement in connection with a snow management is costly. For the measurement of the ski area, transmitter, relay station and the equipment of the snow groomers, several 10,000 euros have to be spent and an additional 5000 to 6000 euros for each snow groomer. See Peter Gaide: Kässbohrer and Prinoth - Der Zweikampf , Brand eins magazine, 2013.
- ↑ a b c https://www.swissinfo.ch/ger/hightech-auf-den-pisten_keine-verschendung-von-schnee/43689700
- ↑ a b https://www.br.de/nachrichten/bayern/ffektenfuchs-wie-klimaschaedlich-ist-skifahren,RC0NgkF
- ↑ a b c OECD (2007) Climate Change in the Alps: Adaptation of Winter Tourism and Natural Hazard Management. https://www.oecd.org/berlin/37999714.pdf
- ↑ https://www.deutscherskiverband.de/ueber_uns_umwelt_fragen_techn_de.html
- ↑ Emissions compared to the previous Euromot IIIa or Tier 3 levels.
literature
- M. Fauve, H. Rhyner, M. Schneebeli: Slope preparation and slope maintenance - The manual for the practitioner . SLF Davos 2002.