Wingskaters on black ice

Black Ice

Alex Humpel und Patrick Koller: Wingskating on magic Silsersee/Engadin.

When the temperature is below freezing and the wind is calm, such under a high atmospheric pressure at night in the fall, a thin layer of ice will form over open water of a lake. If the depth of the body of water is large enough, its color is black and can be seen through the ice, thus the name black ice.