Answer:
Strong winds that blow for a long time over a great distance.
Step-by-step explanation:
Generally, the biggest and most powerful wind-generated waves are produced by strong storms that blow for a sustained period over a large area. Huge and big waves, or swells, can travel over long distances. The size of the wave depends on wind speed, wind duration, and the area over which the wind is blowing. If The speed of the wind is more, it stays for along time and it covers a larger distance then the waves produced will be very powerful and large.