Francis Bacon was no expert on winter sports. Nevertheless, some 400 years ago he had this to say: "The rising unto place is laborious, and by pains men come to greater pains; and by indignities men come to dignities; the standing is slippery, and the regress is either a downfall, or at least an eclipse."
Many of those who have come to grief en piste would find common cause with Bacon's sentiments - albeit that they referred to the perils of high office rather than those of an Alpine ski-slope.
A slippery standing, however, is essential for a skiing holiday. To experience a winter break without the snow is akin to going on a summer outing only to find that the beach has been removed. But nowadays nature's deficit can be supplied by artificial snow. Artificial snow is manufactured in a snow cannon. The first requirement is water, in the form of water droplets in a very fine spray.
The second is a plentiful supply of "sublimation nuclei", tiny particles suspended in the air on which the embryonic snowflakes can be made to form. And the third essential is a very low temperature: only when the air temperature is reduced to 10C or even lower, can a plentiful crop of snowflakes be obtained. The most difficult part is finding the right nuclei on which to grow the snowflakes. Polystyrene granules have been tried, but they are less than satisfactory; the most effective nuclei, it seems, are tiny bacteria bred specially for the purpose. These are added to compressed air, which is stored at a low temperature to start with and then experiences another sharp drop in temperature with the reduction in pressure as it is suddenly released.
The mixture of bacteria and cold air is combined with a very fine spray of water in the cannon, and as the mist crystallises, a shower of millions of bright fluffy snowflakes shoots forth onto the mountain slope.
Like most things artificial, man-made snow has disadvantages.
It has a denser molecular structure than the real thing, so that unless the air temperature is very low indeed, it is liable to compact into lumps of ice which make life difficult, and even dangerous, for skiers. The process is also energy intensive and requires vast quantities of water. But despite its name, artificial snow is real snow. It is only "unreal" in the sense that it has not been produced by natural weather conditions; but like ordinary snow it consists of frozen water crystals.
It is entitled to the name no matter how these crystals may have been produced.