A refrigerator used to cool the world's deepest gold mine in South Africa is now being used to make snow in the Alps. The machine was first installed in the 1990s to cool mine shafts reaching 4km (2.5miles) deep, where temperatures can soar to more than 60C (140F). The refrigerator not only worked well, but to the surprise of everyone, also made snow - an amazing sight for mine workers who had never seen snow before.

The device uses a powerful vacuum to create the right conditions for an occurrence called the triple point of water, when water vapour, liquid and ice can all exist at the same time. As some of the water evaporates, the rest freezes into a slurry of ice, which can be turned into snow.

Seeing a new business opportunity from the inadvertent discovery, the manufacturer flew out the Norwegian ski team to test the snow, who pronounced it was good. But it was much tougher trying to convince ski resorts.

However, this September the first of the new snow machines were installed in the Alps, at Pitztal in Austria and Zermatt in Switzerland. These resorts use glaciers as ski runs, giving them a long ski season. But as the glaciers are receding rapidly in the warmer climate of the Alps, so skiers are having to trek farther to reach the ski runs. The artificial snow helps to bridge that gap. It could also become a lifeline for ski runs at lower altitudes, which rely on natural snow. As reliable snowfall has become less predictable over recent years, ski resorts have been facing a very uncertain future.