Abstract: A structure is provided for indoor skiing on artificially made snow. The structure is thermally insulated and contains one or more support towers about which serpentine configured ski ramps are secured to provide relatively long ski run descents for relatively little lateral travel. For snow-making purposes, a small portion of the ski ramp is enclosed with a thermally insulated cubical module having a top and four sides but no floor. The module is track-mounted and self-propelled for movement along the ski ramp and means are provided to reduce the temperature within the module to snow-making temperature. Self-propelled snow-making machines are placed within the module to move down the ski ramp at the same rate of speed as the module. Skiing conditions encountered on outdoor ski slopes are simulated on the indoor ski ramps.