Indoor skiing
Indoor skiing is done in a climate-controlled environment with artificially produced snow. This enables skiing and snowboarding to take place regardless of outdoor temperatures. Facilities for both alpine skiing and nordic skiing are available. History. Since the early 20th century, there have been four major stages in the evolution of indoor snow centres. Firstly, centres that had no refrigeration and used an artificial mixture of materials to create a surface substance something like snow, the first of these opened in Austria and Germany in the 1920s. The first recorded indoor “snow” slope was created at Berlin’s  Automobilhalle in April 1927 gaining worldwide attention. According to contemporary reports a wooden slope was created about 720 feet long and sixty feet wide. The "snow" substitute used was invented and later patented by a British diplomat, L. C. Ayscough, and involved a mixture of powdered mica, soda crystals and sawdust spread on a brush matting surface. The Berlin government were concerned about health risks from the mixture and commissioned the then head of its Municipal Health Bureau, Dr. Wilhelm von Drigalkski, to check it was safe for public use. He confirmed that it was and an order for 200  tons of the material to be delivered by train was placed. The slope was initially popular and a company was founded to build more slopes in Dresden, Munich, and Frankfurt. It is not known if these were ever created. A second indoor centre using "Ayscough snow", planned to be a more permanent facility, opened in Austria in November 1927. Known as "Schneepalast" (German: Snow Palace), it was opened in the Austrian capital Vienna in the abandoned Vienna Northwest Railway Station established by the Norwegian ski jumper Dagfinn Carlsen. The track in the ski area was built on a wooden ramp . A ski jump made it possible to jump up to . Skiers had to walk up the artificial mountain, because there was no ski lift. However, sledges could be pulled up with an electrically-operated system. The artificial snow had been made by the English experimenter James Ayscough from soda. After the initial excitement enthusiasm for "Ayscough snow" rapidly waned however as users decided it was not particularly slippery and the initial whiteness rapidly discoloured. The Vienna facility closed in May 1928. The second attempt at indoor snow centres came three decades later with the first centre that used real snow  or crushed ice which was transported inside to a slope covered by a roof and open to urban skiers during cold months of the year in the city of Sayama, Japan. This centre opened in 1959 and continues to operate, although now with on-site snowmaking rather than bringing in snow by lorry. Thirdly came the first generation of refrigerated indoor centres which used either a chemical mixture to simulate snow or scraped ice. The first three of these opened in 1988, each claiming to be the first in the world. These were MtTheBarton in Adelaide, Australia, Casablanca in Belgium , and Ski in Tsudanuma in Japan. The fourth and current stage of indoor snow centre development came when centres which used ‘real snow’, made by snow-making machines, with no chemical additives, began to appear. These are now the norm for most of the 140 centres that have been built since the first, which was The Snowdome at Tamworth in the UK which opened in May 1994. Present Day. Since the first indoor snow centre was built in Berlin in 1926, 149 indoor snow centres have been, most of them since 1990. 113 are currently operational in 35 countries on  6 continents. Most offer skiing and snowboarding but some, primarily in sub-tropical areas in southeast Asia that do not normally see natural snowfall, exist as snow experience centres offering activities like sledging, snowman building and snowball fights. The number of centres being built continues to grow and 2019 saw more indoor snow centres open worldwide than any other year. Analysis of the last three decades of indoor snow centre construction saw 2010-19 had the most indoor snow centres built (60), up from 43 between 2000 and 2009 and 34 built in the 1990s. Asia (especially China) saw the  most-new indoor snow centres built since 2010, as it did in the 1990s (back then most were built in Japan). Between those two decades Europe built the most facilities in the first decade of this century. The past decade saw the first indoor snow centres open in Africa (Egypt), North America (USA) and South America (Brazil). Three of the five-biggest indoor snow centres in the world, including two with 50,000sqm+ (500,000+ square feet) indoor snow space, opened in a 12 month period from March 2019 to March 2020. Many of the indoor snow centres built in recent  years are in China which has 34 centres, almost five times more than the next closest country (The Netherlands, with seven). China’s SUNAC group has become the world’s largest operator of indoor snow centres, operating seven centres, including the world’s three largest. Two more are under construction, most of these opened in 2019-20. List of Alpine ski halls by country. Australia Belgium China France Germany Indonesia Japan Lithuania Netherlands New Zealand Norway Russia Spain United Arab Emirates Egypt United Kingdom United States of America