Wind causes waves on the ocean or freshwater lakes. The wind transfers its energy to the water through friction between the air molecules and the water molecules.
A strong wind for several hours can make large waves, which are hazardous to diving. A wind from another direction flattens the waves, reducing their energy, or the waves encounter shallow water and break as surf. The waves break in shallow water because the wave bottom is slower on the seabed, causing the top of the wave to become unstable and break.
You will need to learn special techniques for surf entries. You will also need to learn how to enter and exit the surf zone while watching the wave pattern. This is because waves can approach from different directions, colliding into each other to make a large wave or canceling each other out and making a series of small waves. Diving in large surf makes for low visibility and hazardous conditions!
Tidal waves or tsunamis are usually caused by underwater volcanic eruptions, earthquakes, or landslides.