swell is the wave motion caused by a meteoro logical disturbance,which persists after disturbance has died down or moved away.
swell often travels for considerable distances out of its generating area,maintaining a constant direction as long as long as it keep in deep water.as the swell travels away from its generating area,its height decreases though its lenght and speed remain constant,giving rise to the long low reqular undulations so charteristic of swell