The Gulf of Riga is a prominent feature of the Baltic's Estonian and Latvian coasts. The Baltic receives the drainage from a large part of northern Europe, including Estonia, Latvia, Lithuania, northern Germany, and nearly all of Sweden. Surface currents of low salinity flow constantly from the Baltic to the North Sea, while deeper currents, with a larger salt content, flow in the opposite direction. Tidal action is apparent only in the southern part of the Baltic. Storms are frequent in the Baltic Sea and often cause severe damage to ships.
Easterly winds are particularly dangerous because they create huge tidal waves.
Navigation in the northern part of the Baltic is suspended during the winter and early spring because of ice. The Baltic is of great commercial importance to northern Europe.