A rare sight of iridescent clouds appeared in southwest China province of Yunnan Monday.
The thin layer of colorful clouds appeared with the rise of the sun at Shangri’La on January 4. The phenomenon also appeared in such cities as Dali and Kunming in 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. Under suitable weather conditions, the sunlight and the clouds form a suitable angle. As the sunlight passes through the clouds, the ice crystals in the clouds separate the solar spectrum through refraction, causing rainbow clouds.