Kelvin wave: Quick Facts

Written and fact-checked by

The Information Architects of Encyclopaedia Britannica

Last updated

Oct. 18, 2026

News •

A Kelvin wave is raising sea levels along the West Coast • Oct. 16, 2026, 4:48 PM ET (NPR)

Photos and Videos

Images of sea-surface height taken during the El Nino episodes of 1997 and 2015.

A line graph compares types of surface waves by energy and wave frequency, showing ordinary tide waves, long-period waves, wind waves, and capillary waves, with causes such as wind, storms, and earthquakes labeled above each category.

Map of the tropical Pacific Ocean highlighting the four ENSO (El Niño-Southern Oscillation) regions: Niño 4, Niño 3.4, Niño 3, and Niño 1+2. The regions are marked as colored rectangles along the equator from near Australia to the coast of South America, illustrating key zones used to monitor El Niño and La Niña climate events.

False-color map of the equatorial Pacific Ocean showing sea level variations in millimeters, with blue and purple indicating lower sea levels and red and white indicating higher sea levels appearing along the Equator, suggesting the passage of a Kelvin wave and early El Nino development in 2023.

See All Videos and Images →

Topics

ocean wave