A swell wave is a uniform, symmetrical wave that has moved beyond the point in the ocean where it began, according to the Water Encyclopedia. Unlike a typical wind wave, the swell wave is stable in the direction it travels and frequency.
Swell waves are grouped by the strength of their wavelengths. Swell waves with greater wavelengths are larger and travel from their point of origin faster than ones with smaller wavelengths. The size of a swell wave varies and depends on how far it has traveled and how strong its wavelength. According to Stormsurf.com, the highest a swell reaches during a typical storm is 35 feet, with a swell of about 20 seconds.
If a storm system is close to land, swell waves are likely to break on the shore. As the storm approaches, these waves hit the land with greater ferocity. However, unless significantly bigger than normal waves, swell waves can appear like an ordinary wind wave.
