Lake Erie has the greatest maximum water-level fluctuation caused by seiches among the Great Lakes.
A seiche is a standing wave that makes water oscillate from one end of a lake to the other. Strong winds and changes in atmospheric pressure can push Lake Erie’s water toward one shore; when the forcing stops, the water rocks back across the basin. Because Erie is long, relatively shallow, and aligned along a prevailing wind corridor, the effect can be exceptionally large.
A famous 1844 seiche at Buffalo, New York, reportedly produced a water-level change of about 22 feet, or 6.7 metres. Modern storms can also cause dangerous rapid changes at shorelines and harbours.
Seiches are not tides. They are temporary basin-wide oscillations, although local wind setup can combine with them and make flooding worse. The lake’s shallow shape amplifies the response compared with deeper Great Lakes.