The Tidal Estuary of the Varzuga River (Russian Subarctic): First Information about the Winter Hydrological Regimе

The paper shows that the lower reaches of the Varzuga River (Terskii coast of the White Sea) are subject to a strong effect of sea tides, which can be seen in level variations and the periodic occurrence of reverse (tidal) currents and saltwater intrusions. The data was obtained during the expedition carried out in winter 2020 at the estuary of the Varzuga River along with data collected by the authors at the estuaries of other rivers in the White Sea basin (the Mezen, Onega, Umba, Kyanda, Tamitsa, and Kuzreka rivers) in 2017−2019. In this context, characteristics of the processes mentioned above are given and the factors that affect them (channel relief, river flow, tides, and ice) are discussed.