What is a seiche? (pronounced "saysh")

Like water sloshing in a bathtub, seiches are tide-like rises and drops in Great Lakes coastal water levels caused by prolonged strong winds that push water toward one side of the lake, causing the water level to rise on the downwind side of the lake and to drop on the upwind side. When the wind stops, the water sloshes back and forth, with the nearshore water level rising and falling in decreasingly small amounts on both sides of the lake until it reaches equilibrium.

For more information about Great Lakes water levels and coastal processes, visit our  Coastal Engineering Advisory Services Web site!

© 1997 University of Wisconsin Sea Grant Institute
created by wittman