Juan Fernandez Islands are located about 800 km from the coast of Chile. The largest of them — Alexander Selkirk Island and the island of Robinson Crusoe. This volcanic island, which can boast of the high peaks. High enough to disturb the flow of air over the ocean. When an object, such as an island, interferes with the movement of air, on the lee side of it form the Karman vortex street. They are double rows of spiral vortices, which become discernible through the clouds.