When wind blows over a water surface, waves are created. At high wind speeds the waves will start to break. Water droplets appear, but the water surface is still well defined. But if we consider stronger and stronger winds like in case of a hurricane, it seems to me that the water surface should break pretty much everywhere. If you descent from some altitude towards the surface, you'll enter a region of air mixed with water droplets and as you descent further the fraction of water in the air will increase without encountering a well defined boundary between the air and the water. A lot of air is also injected into the water, so even well below sea level there should be a lot of air bubbles, making the scene from there look quite similar to that well above sea level.
The question is then whether there is a well defined phase transition where at at low wind speeds when you do have some amount of water droplets in the air and air bubbles in the water, there is still a rigorously defined water surface while at higher winds speeds the water surface is gone. This can perhaps be treated using methods based on the dynamic renormalization group. In the case of low wind speeds, if we consider course graining and scaling such that we zoom out and we don't see the small details anymore, then the droplets will vanish from view and we're left with a calm sea. In the latter case, the dynamics could be scale invariant, so no matter how much you zoom out, you don't get to a calm sea surface anymore in the scaling limit.