How can seiches create large differences in water level across Lake Erie?

Seiches create large differences in water level across Lake Erie primarily through the interaction of wind and atmospheric pressure with the lake's physical characteristics.

When persistent winds blow along the lake's major axis, they push surface water toward one shore, a phenomenon known as wind setup. This causes water to pile up temporarily at one end of the lake, creating a significant tilt in the water surface. When the wind stress or atmospheric pressure gradient subsides, the accumulated water flows back toward the opposite side to restore equilibrium. This movement initiates an oscillatory wave, or seiche, which travels back and forth across the lake.123

Because Lake Erie is relatively long and narrow, it is particularly susceptible to these longitudinal oscillations. Intense storms can amplify this effect, resulting in dramatic water level differences between opposite ends of the lake, such as between Buffalo, New York, and Toledo, which have been recorded at 13 feet or more.123