Winter Sports · General · Snow and mountain science
How Are Ski Slopes Prepared? Piste Grooming and Piste Bashers
Ski slopes are prepared with tracked grooming machines known in the industry as piste bashers (in Turkish, ratrak). According to the handbook of the Swiss Institute for Snow and Avalanche Research (SLF), the blade at the front moves the snow and levels the surface, the tiller at the back compacts the snow and breaks up its grains to create a smooth, durable surface, and the winch (cable) makes it possible to prepare steep slopes. According to the SLF, the best time to groom is shortly after the slopes close: in the morning, a slope groomed in the evening is more than twice as durable as one groomed in the early hours. The slopes are closed while grooming is under way; according to the German Alpine Club, there is danger to life especially when a winch is in use.
A piste basher is a vehicle that moves on tracks over the snow and prepares the slopes; the name is widely used in the industry for these vehicles (see the piste basher entry in our glossary). A piste basher has three main tools:
Tool
Position
What does it do? (SLF)
Blade
Front
Moves the snow, levels bumps and hollows
Tiller
Back
Compacts the snow and breaks up its grains; creates a smooth surface. According to the SLF, it is the preferred equipment
Winch (cable)
On top
Anchors the vehicle to a point higher up so it can work on steep slopes; helps carry snow that has been pushed downhill back up
The finely ridged “corduroy” surface skiers see in the morning is the pattern left by the tiller.
When are the slopes groomed?
According to the SLF's handbook, the best time to groom the slopes is shortly after the slopes close. Groomed snow gains strength as its grains bond together and it hardens; this needs a rest period of at least about 8 hours. According to one study, at 9 a.m. a slope groomed in the evening was more than twice as durable as a slope groomed at 4 a.m. In spring, wet snow is groomed as it starts to freeze.
That is why slopes are usually groomed in the evening and at night; in the first hours of the morning the slopes are at their best. As the day goes on, heavy use, sun and temperature change the surface; for snow types, see our guide Powder, Wet, Icy and Artificial Snow.
Machine-made snow and grooming
Early in the season or when there is little snow, the snow produced by snow guns builds up in piles; piste bashers spread these piles over the slope and compact them. Because machine-made snow is much denser than natural snow, it forms a more durable base. We explain how artificial snow is made in our guide How Do Ski Resorts Make Artificial Snow?
Safety: stay off closed slopes
The slopes are closed while grooming is under way. According to the German Alpine Club (DAV) rules for ski touring on pistes, slopes are closed for safety reasons during grooming work, and there is danger to life especially when a winch is in use.
The winch cable: On winch piste bashers, the vehicle is attached by a cable to an anchor point higher up; the cable runs across the slope and shifts position as the vehicle moves. Manufacturers use systems that continuously monitor the cable force and the remaining cable length, but the danger does not go away for anyone on the slope.
Do not go on the slopes outside lift hours: The slopes are closed in the evening and at night; even ski tourers need to follow the resorts' rules.
If you see a piste basher during the day: Sometimes piste bashers also work during the day; do not approach the vehicle, keep a wide distance and follow the staff's signals.
Groomed and ungroomed slopes
Some slopes are deliberately left ungroomed: mogul runs and, at some resorts, marked but ungroomed routes (yellow or orange “ski routes” in Europe). These are more difficult and require experience; for details, see our guides Ski Run Colours and Difficulty Ratings and Mogul (Bump) Skiing Technique.
The first hours of the morning
The first run of the morning on a freshly groomed slope is one of the most enjoyable moments in skiing. On an activity holiday, the day is planned around this: technique work early in the morning on smooth slopes, practice in the afternoon. On Doğadayız winter programmes, heading out early with the group to enjoy the smooth slopes and talking over the day together in the evening turn the programme into a social adventure holiday. For programmes, see our winter activity holidays page.
Doğadayız Packages
Doğadayız packages for your level
Winter activity holidays with accommodation, ski pass and equipment included, shared with a group.
The easiest way to learn to ski: a winter activity holiday
An activity holiday puts a sport at the heart of your trip: transport, accommodation and meals are planned, so you can focus on learning on the slopes. On Doğadayız winter activity holidays, accommodation, ski pass and ski or snowboard equipment are included in every package; course packages include basic lessons with instructors affiliated with the Turkish Ski Federation, while experience packages let you practise on the slopes at your own level.
What makes the programme different is the group: sharing the slopes with people at a similar level, dinners and nights out together, and a group leader by your side at all times. Solo travellers become part of this social adventure holiday from day one. That is why we describe our programmes as a social adventure holiday.
It is the tracked vehicle that prepares ski slopes. The blade at the front moves and levels the snow, the tiller at the back compacts it to create a smooth surface; winch models can work on steep slopes.
When are ski slopes groomed?
Usually in the evening and at night, shortly after the slopes close. According to the SLF, in the morning a slope groomed in the evening is more than twice as durable as one groomed in the early hours, because the snow hardens as it rests.
Can you ski while a slope is being groomed?
No. The slopes are closed for safety reasons while grooming is under way. According to the German Alpine Club, there is danger to life especially on slopes where winch piste bashers are working.
Artificial snowmaking means snow guns spraying water into very small droplets and freezing them in the air; no additives are used, only water and air. According to the slope preparation handbook of the Swiss Institute for Snow and Avalanche Research (SLF), the water is broken up at a pressure of about 12–60 bar into droplets of 0.1–1 mm; the droplets freeze in the air and bond together on the ground to form snow. Snowmaking depends more on humidity than on air temperature: according to the SLF, at a wet-bulb temperature between −2 and −4 °C snowmaking can only just begin. In practice, at most about 2.2 cubic metres of snow are obtained from one cubic metre of water. In Türkiye, Erciyes, for example, has 154 snow guns.
The snow on the slope is not the same every day. According to the definitions of MeteoSwiss, the Swiss meteorological office, powder is fresh snow that has not yet been compacted; hard snow is snow compacted by melting and refreezing or by wind, and its most extreme form is crust; corn (spring) snow is moist snow whose surface thaws in the daytime sun, typical in spring. Artificial snow (machine-made snow, the name scientists prefer), according to the WSL Institute for Snow and Avalanche Research (SLF), is much denser than natural snow (fresh natural snow averages ~100 kg/m³, dry machine-made snow ~400 kg/m³) and consists of small, round grains of 0.1–1 mm. That is why machine-made snow creates a more durable but harder slope.
A piste map has three layers: lifts (gondolas, chairlifts, drag lifts and magic carpets; usually straight lines), runs (blue, red and black by difficulty; often numbered) and services (rental, first aid, restaurants, meeting points). When reading the map, first find where you are and your return point, then the runs that suit your level and the lifts that take you up to them. The live board at the resort entrance shows which lifts and runs are open (green) or closed (red) and any avalanche warning; plan your day accordingly.
