ABSTRAKAmathematicalmodelofthemechanismoftheappearanceofantisymmetricvortices during the propagation of freshwater into the seawater which is observed, in particular, at the exit from the Baltic Canal connecting the Vistula Lagoon and the Baltic Sea is constructed in the work. In particular it is shown that the main reason for the vortex formation in this case is the Coriolis force. The exact dependence of the circulation of velocity on time for the three simplest types of the tongue of the intrusion of freshwater is calculated analytically in the work as well.