We start from the beginning. The reason why we produce snow is to be able to open the facility as early as possible, regardless of the weather, but also to be able to offer a long season with many slopes open. The difference between produced snow and natural snow is that the former has a more compact snowflake which means that it melts more slowly, which means that we can keep the slopes in good condition even if a large part of the natural snow would melt away. It is usually said that 10 centimeters of snow produced corresponds to approximately 80 centimeters of natural snow.
If sub-zero temperatures had been the only thing that counted, snow-laying would have been an easy process to understand, but there are more factors that come into play. Before the snow cannons start, the wind and humidity must also be taken into account. The wind direction is important to get as much snow out of a cannon as possible, as the snow needs to reach far into the hill to cover as large an area as possible. The humidity matters because it can reveal if it is colder than what the thermometer shows. By frequently taking into account and controlling all these factors, our snow plows can get a better idea of how much snow can be produced and how many cannons we can launch. Dry air is the absolute best for producing snow and if the thermometer also shows between minus 8 and minus 15 degrees then the conditions are optimal.
To cope with a season, a descent needs to have a snow depth of about 1 meter and regardless of the amount of natural snow, the snow produced plays an important role. In fact, a perfect slope feels best from a combination of the two types of snow, usually with snow produced as a basis. Once the natural snow falls, it is mixed with the base layer in order to achieve the best possible snow structure for skiing. The result? A descent that lasts a very long time and which provides a fantastic surface where you can enjoy long wonderful carving turns.
Maybe you recognize the pattern you see in the snow in the picture? The so-called Manchester pattern, which both piste machinists and skiers long for, is formed when preparing the snow. But why is the pattern used and what does it mean when the piste machines prepare the snow?
Prepare is a collective word for what is commonly called pissing. During piste, the piste machine mills the snow to mix it and then lays a Manchester pattern using the mat at the back of the machine. The striped cuff pattern helps the snow to cool down faster and the ride feels both softer and more comfortable than if the surface had been completely flat. That it is also a delight to the eye is a bonus!
That it gets icy on some slopes, you have guaranteed to see and experience during a visit to a ski resort. A common misconception is that this is because the hill has not been piste, but the most common explanation has, as so many times before, to do with the weather. When hot days are followed by very cold nights, a form of ice formation forms on the surface of the snow. This icing usually remains until the next night, when we want to avoid piste too close to the opening. If we piste just before skiers go out on the slopes, the snow does not have time to cool down properly in the Manchester pattern. Instead, the snow becomes more porous and rises much faster, which neither we nor our guests want.
However, there are special cases when you want to be out with the piste machines as close to the opening as possible and that is when there is a lot of natural snow. Then we make sure to piste in the areas where our youngest guests will go so that they get the chance to develop on a more easy-to-ride surface.