Iridescent clouds appear in Yunnan

A rare sight of iridescent clouds appeared in China's Yunnan Province on January 4. The thin layer of colorful clouds appeared with the rise of the sun. The phenomenon also appeared in such cities as Dali and Kunming in a different segment of the time. Experts say that iridescent clouds, known as "rainbow clouds", is a kind of optical phenomenon produced by the diffraction of sunlight by individual tiny ice crystals of a cloud.