👉 A swell is a sudden increase in water level or pressure caused by an ocean, sea, lake, river, or other body of water. Swells can be caused by a variety of factors including changes in temperature, circulation patterns, and natural phenomena like earthquakes or volcanic eruptions. Swells are often seen as a response to the movement of waves, which are caused by the motion of the water itself. Swells are an important part of oceanography and can provide valuable information for predicting weather conditions