vuorovesivirtaus

Noun

 * 1)  tidal current flow of water caused by the rise and fall of the tide
 * 2) riptide, rip tide particularly strong tidal flow which may e.g. carry a swimmer far offshore

Usage notes
The tide is almost unnoticeable in the Baltic Sea and therefore the terminology is "underdeveloped" in this particular field. A "riptide" may be called, if necessary to make a difference to more ordinary tidal currents.