The principle of snow generation is the same for fan guns and snow lances. This machine-generated snow simulates natural snowfall in that the "nucleators" produce a mixture of water and compressed air which expands in the atmosphere, allowing nuclides (= snow nuclei) to develop. At the same time, the nozzles atomize water into fine droplets, which combine with the nuclides and freeze to form small snow crystals on their way down to the ground.
Nature also needs to play its part for the snow-making process to function correctly. Both air temperature and air humidity play an important role. The term used in snow-making technology is wet bulb temperature which is a combination of temperature and relative humidity. The more humid the air, the less moisture it can absorb. This means that when atmospheric humidity is high, lower temperatures are required in order to be able to produce snow. TechnoAlpin snow guns function from a wet bulb temperature of -2.5°C upwards. At a lower level of atmospheric humidity of 20% this wet bulb temperature of -2.5°C will already be reached at +3°C. At a high level of atmospheric humidity of 90%, however, temperatures of -2°C are needed in order to arrive at the wet bulb temperature of -2.5°C. This means that, at a low level of atmospheric humidity, the snow-making process also functions at temperatures slightly above zero, but at a high level of atmospheric humidity temperatures below freezing point are needed. Temperatures around freezing point are said to be limit or marginal temperatures.
The water temperature is also a key factor for the snow-making process at marginal temperatures. Cooling towers are used to bring the water to an optimum temperature in order to increase the efficiency of the system or to be able to put it into operation even earlier.