Glossary · Weather & oceans
Swell
Also called: Houle, mer, état de la mer, sea state, vagues, waves, mer croisée
Long, regular waves formed by distant wind; wind waves are raised by the local wind.
The sea state combines swell, sometimes from thousands of miles away, and wind waves, shorter and choppier. When the two cross, the sea becomes confused and hard on boats. In the Southern Ocean, swell can reach several metres.
More in Weather & oceans
Page reliability
No source yet · updated 30 Sept 2026