seiche (SAYSH) - n., a short-term standing-wave oscillation of the water level in a lake, typically caused by atmospheric conditions.
Though sometimes there's a seismic cause. Can also be in largely land-locked harbors, bays, or even seas (autumnal seiches in the Baltic Sea can cause flooding in St. Petersburg). The period of the up-and-down motion at a particular spot can range form minutes to hours, depending on the size of the body and which harmonics the waves are using. Adopted around 1839 from Swiss French, where it's used to describe occasional apparent tidal motion of Lake Geneva and other alpine lakes, origin obscure but possible from German Seiche, sinking.
---L.
Though sometimes there's a seismic cause. Can also be in largely land-locked harbors, bays, or even seas (autumnal seiches in the Baltic Sea can cause flooding in St. Petersburg). The period of the up-and-down motion at a particular spot can range form minutes to hours, depending on the size of the body and which harmonics the waves are using. Adopted around 1839 from Swiss French, where it's used to describe occasional apparent tidal motion of Lake Geneva and other alpine lakes, origin obscure but possible from German Seiche, sinking.
---L.