Steady winds produce a pattern on the sea’s surface like parallel furrows in a field
Researchers are still trying to unravel the complex interactions between wind, waves and currents. One of the most visible results of these interactions is Langmuir circulation, which produces a pattern on the water surface like parallel furrows in a field. These lines are known as wind streaks or windrows, and occur only in steady winds of more than 7mph.
Source: Guardian Environment