US Patent 7124958 Controlled snow-making process and apparatus

A method and apparatus suitable for producing an artificial snow surface for tire evaluation is provided. The process provides for manufacturing a series of snow layers, each layer followed by a packing and a grooming step to provide a multi-layered snow surface. Desirable shear strength properties of the snow surface are enhanced by a surface grooming technique that applies a layer of water to the upper snow surface followed by grooming of the surface. The manufactured snow surface allows the testing and evaluation of tires that compares favorably to tire evaluation data obtained from outdoor testing facilities.