Snow grooming

Classic tracks at Drottningholm Palace in Sweden.

Snow groomer with standard equipment for ski slopes.

Snow grooming is the process of manipulating snow for recreational uses with a tractor, snowmobile, snowcat, piste caterpillar, truck or snowcat towing specialized equipment. The process is used to maintain ski hills, cross country ski trails and snowmobile trails by grooming (moving, flattening, rototilling, or compacting) the snow on them.

Equipment

Modern groomers built for ski slopes employ front mounted, hydraulically operated blades, powered rotary tillers and specialized shaping equipment for not only maintaining ski slopes, but also for building half pipes, ski/snowboard terrain parks and snow tube parks. Cross country ski trails are also groomed in similar fashion, but use specialized drags that imprint ski guides instead of grooming a wide path suitable for high speed snowmobile use.

A snow groomer is a tracked vehicle equipped in front with a shovel (or dozer blade) and behind with a cutter (or roller). It is usually driven by diesel engines. When the machine drives over a snowfield, it pushes snow ahead of it and, at the same time, smooths out any surface unevenness.

Manufacturers include Formatic, Kässbohrer, Prinoth, Ratrak, Logan Machine Company, Tucker Sno-Cat, Snow Trac, Thiokol, Ohara Corporation / AZTEC

Snow groomers can handle very steep gradients due to their low centre of gravity and large contact area, but they can also be assisted by winches. Using cable lengths of up to 1,200 metres and a tractive force of up to 4.8 tonnes, winches can support the machines on steep slopes.^[1]

Snow groomers warn skiers and snowboarders with visual or acoustic signals. Groomers are mostly sent out during the night time after the close of the ski area so as not to interfere with daily and night skiing.^[2]

Due to their mobility and low ground pressure (typically 0.040 to 0.060 kg/cm² (about 4 to 6 kN/m²) snow groomers are sometimes used elsewhere, e.g. for agricultural purposes, moving bulk goods, working on peat bogs or at biogas sites.^[3]

Snow farming

Snow farming is the use of obstacles, equipment and knowledge about management of snow in order to strategically manipulate snow coverage. Often this is done for the purpose of skiing or even preventing snow drift in certain areas like roads. The most popular obstacle is the snow fence, which is used to create drifts and collect more snow in a given area than would otherwise naturally occur. The snow can be moved to other areas and groomed with the use of a snow groomer. Sometimes the snow fence is readily movable in order to maximize the collection of blown snow, despite wind direction changes.

A groomer will usually go out to pack the snow and improve skiing and snowboarding and snowmobile trail conditions. The resulting pattern on the snow is known as corduroy, and is widely regarded as a good surface on which to ski or ride. Snow groomers can also move snow made by snow machines.

Snow grooming and the associated snow packing is known to have negative effects. The compaction reduces porosity, permeability and water holding capacity of the mountain slopes, while heat flow rates and length of snow retention are seen to increase. This combines to produce longer and deeper frost penetration into the soil, causing negative effects on the underlying tussock.

References

1. Neue Windentechnologie für steilste Hänge (Sherpa-Winde, Prinoth) ISR Internationale Seilbahn-Rundschau 22 April 2011, retrieved 5 September 2014
2. Snowmakers, snowmaking prevail when Mother Nature is uncooperative - Pocahontas Times - Mountain Times, Vol. 6 No. 2 February 2007
3. Pistenraupen zum Bewegen von Hackgut TEST Pistenraupe Prinoth LH 500, Anwender: Thermo Wipptal AG, ([photos dated 15 June 2011), retrieved 5 September 2014