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With the latest rains, the flow of the Ter River, which supplies the Sau reservoir, has been increasing, but what stands out in this series of photographs in La Vanguardia’s Readers’ Photos is seeing it steaming.

The Ter river rises in Ulldeter at 2,480 meters of altitude, at the foot of a glacial cirque in the Pyrenean region of Ripollès, very close to the town of Setcases.

The steaming water is known as arctic smoke. It is produced by the difference in temperature of the water and the air mass, as in this case in Manlleu.

It occurs when rivers, lakes, reservoirs or even the sea are at a much milder temperature than the air at certain times of the day, especially at dawn.

Smoke is produced in this contact zone between the different temperatures of water and air, giving rise to this spectacular phenomenon, which can generate a ghostly image.