"A rare natural phenomenon was seen at the Fushun Reservoir in northeast China on Sunday, creating unusual wave patterns that appeared to move vertically across the water's surface, as shows the footage from the site. The reservoir, a major water source and scenic area in Fushun, Liaoning Province, drew attention as the waves briefly resembled drifting clouds before dissipating. The phenomenon, known as 'haihao' or the 'sea of vastness,' is a type of evaporation fog that can form over coastal waters or reservoirs, experts say. It occurs when warm water releases large amounts of vapour into much colder air, creating thick white fog that can make the surface appear to 'boil.' The effect is usually seen when air temperatures drop suddenly, producing a sharp contrast between the water and the air. The Fushun Reservoir, officially known as the Dahuofang Reservoir, has a total storage capacity of over 2.18 billion cubic metres."