Wind Waves

ocean · weather · water physics

Wind makes waves. When wind blows across the ocean or a lake, it pushes on the water's surface and creates waves. The stronger the wind blows, the bigger the waves can grow.

Distance matters a lot. Scientists call the stretch of water where wind blows over it the "fetch." A longer fetch means the wind has more space to push the water, so waves get much bigger.

Waves travel far. Ocean waves created by wind can travel thousands of kilometers across the water before they finally reach a beach or coast. That means a wave that started near Japan could eventually crash on California.

Size has limits. Wind waves on Earth can grow taller than a 10-story building, reaching over 30 meters high. But they stop growing when the wind gets too weak, the wind doesn't blow long enough, or the water gets too shallow.

Ripples to giants. The smallest wind waves are tiny ripples you can barely see, but they keep growing if the wind keeps pushing. The same wind and water that makes ripples can eventually make giant waves that surfers love.