Switzerland's alpine resorts are promising skiers that it will be a white Christmas - mostly because of artificial snow.
swissinfo's Dale Bechtel reports from two top resorts, Gstaad and Arosa, where increased use of the technology is guaranteeing perfect pistes.
Thanks to Eddi Welti, it was snowing when I hit the slopes above Gstaad in early December. Welti is the snow-maker for the Eggli ski lift company in the Bernese Oberland resort.
Sitting at his computer in a non-descript wooden shed, Welti can switch the snow on or off with a simple mouse click.
The use of snow cannon has been repeatedly challenged by environmentalists, who claim they damage the fragile Alpine ecosystem. But they have become as much a part of the winter landscape in the Swiss Alps as the countless chairlifts and cable cars.
Welti assures me that the recipe for man-made snow is simple: you take large amounts of water, add compressed air, wait for the right temperature and then blow it through a portable wind machine called a snow cannon.
Alpine resorts like Gstaad do the lion's share of their business during the ski season, so ensuring there is snow on the slopes is essential.
This has become even more of an issue in the face of global warming. Gstaad lies at a lowly 1,000 metres above sea level, and at Eggli where Welti works his winter magic, the slopes only go up to 1,600 metres.
Scientists are predicting the so-called snowline in the Swiss Alps will rise to 1,500 metres in the coming decades.
It is surprising then that Hanuola Brunner who works at Arosa would have to worry about making snow.
One of the highest resorts in the Swiss Alps, the ski area in the eastern resort lies between 1,800 and 2,600 metres above sea level. But Arosa, like Gstaad, has invested heavily in snow-making equipment.
"We want to guarantee snow at Christmas," says Brunner. "It would be a catastrophe if we didn't have any snow over the Christmas period.
"We would lose half of our business for the whole season if we weren't able to promote the fact that we have snow at this time."
Even though it's usually cold at this high altitude from November onward, there's no guarantee that snow will fall in sufficient quantities.
St Moritz was a case in point last year. Winter was very cold but there was no snowfall for months; artificial snow alone made skiing possible.
Like St Moritz, Arosa is not taking any chances. By mid-December, all of Arosa's runs were already open.
Without man-made snow, Brunner says it would not have been possible at this time to ski from the middle station - located at 2,000 metres - down to the village.
And thanks to the key positioning of snow cannon, there are no brown or icy patches on steeper sections where skiers tend to wear away the snow cover.
Swiss slow start
While snow-making has long been established in North America as well as in countries neighbouring Switzerland, the Swiss only really started investing heavily in the technology in the 1990s.
They were slowed up by environmentalists and referenda, and the Swiss still have a lot of catching up to do.
Man-made snow is used on about ten per cent of Switzerland's slopes, while the average in Austria, Switzerland's main competitor, is about 30 per cent.
Arosa is an exception. It already covers about 20 per cent of its ski area with artificial snow, and Brunner says the Arosa cable car company wants to double this in the near future.
"In order to ensure that we have enough water, we will need to build a reservoir to hold up to 40,000 cubic metres of water," he says.
The use of water is one of the most controversial aspects of snow-making. The leading Swiss environmental organisation, Pro Natura, argues that water is a precious commodity in the Alps in winter since most precipitation falls as snow.
It takes about 300 cubic metres of water - around ten tanker loads - to produce only a thin covering of snow (15cm) over an area of 60 square metres.
Electricity and water
"Snow cannon are noisy and use a lot of natural resources, particularly electricity and water," says Pro Natura spokesman Peter Rüegg.
"The water has to be stored in man-made reservoirs which is yet another scar on the landscape," he adds.
Pro Natura is also concerned about the use of a chemical additive which increases by a couple of degrees the temperature at which snow can be made.
The additive is an ice-nucleating protein derived from naturally occurring bacteria.
Rüegg says the jury is still out on the effects the additive has on alpine vegetation, but Switzerland's Federal Environment Office is less concerned.
It has approved the most common brand, "Snomax Snow Inducer".
Patrick Oppliger of the Swiss company, SMI, which is one of Europe's biggest suppliers of Snomax, describes the snow made with the additive as "technical" rather than "artificial", and says it is harmless.
Arosa is one of the few Swiss resorts to use Snomax and then only sparingly. Welti in Gstaad says it is simply too expensive.
Welti and Brunner are proud of the snow they are making. They both tell me that it is more compact than natural snow, yet retains its powdery consistency so you can ski over it without sinking in.
In the end, skiers have proven they are willing to pay the price for artificial snow.
They fork out the money for the lift tickets and accommodation in the ski resorts, and hence foot the bills.
swissinfo, Dale Bechtel
Swiss cable car companies plan to invest SFr250 million over next three years in snowmaking equipment.
Man-made snow is used on about ten per cent of Swiss ski slopes.
300 cubic metres of water are required to produce a 15cm covering of snow over an area of 60 square metres.