From Coastal Wiki
Definition of Swell:
Waves generated far offshore in the deep sea that propagate onshore.
This is the common definition for Swell, other definitions can be discussed in the article
- The longest waves in the ocean travel faster and dissipate less energy than the shorter waves generated by the same strong wind event. They therefore can reach distant shores whereas the shorter waves cannot.
- Ocean swell waves have longer wavelengths than locally generated wind waves. They typically have small steepness (small ratio of wave height to wavelength).