❖ INCOIS forecasted that high sea waves, also known as swell waves, might hit the coastal states.

❖ In March, swell waves led to flooding in several areas of Kerala — the worst affected were Alappuzha, Kollam, and Thiruvananthapuram districts.

❖ Such flooding events are called Kallakkadal in Kerala.

❖ During such storms, huge energy transfer takes place from the air into the water, leading to the formation of very high waves.

❖ Such waves can travel thousands of kilometres from the storm centre until they strike shore.

❖ Usually, states like Kerala witness swell waves as a result of strong winds in the southern part of the Indian Ocean, where an ocean swell is generated.

❖ The waves then travel north to reach the coast in two or three days.

❖ Tsunamis are around 10 times faster than swell waves.