snowflake

Under this generic term we can include both individual ice crystals and clusters of those crystals which, as they fall through the air and are subjected to continuous jostling, fuse together, resulting in the traditional snowflake. Their size and fluffiness are highly variable, depending on the ambient conditions during the snowfall. The tiny ice crystals that form snowflakes form inside cold clouds, where, initially, supercooled water droplets and minuscule microscopic ice prisms, of hexagonal structure, which act as ice embryos, coexist. The evaporation of the droplets provides the water vapor needed for the crystals to keep growing. They do so through a complex branching process, which varies depending on the temperature and the degree of saturation of the water vapor surrounding the crystals. Their final shape - plate, column, or star - depends on how that pair of variables combines.