Waves are caused by wind blowing over the surface of the ocean. The longer, stronger and further it blows, the bigger the waves will be. There are three kinds of waves:
Where the beach is relatively steep waves can break with considerable force. It can be dangerous to swim in these waves. They are a common cause of broken limbs and back injuries, take care!
The crest of a spilling wave tumbles down the front. If the sandbank where it breaks is shallow, the spilling crest will form a 'tube'. These are the best waves for body surfing.
These never break, because the water beneath them is deep, but they
can knock people off their feet and drag them back out.