Ocean waves are explainable in terms of classical fluid mechanics. Even the appearance of "rogue waves" is simply a manifestation of the superposition principle for classic wave theory. No appeal to quantum mechanics or general relativity is necessary. It's a problem a first-year physics student can solve using vector calculus.
The wave-particle duality of matter is well known, but the effects are only noticeable on the quantum scale. Application of the de Broglie wavelength, for example, to macroscopic particles, like pieces of matter, baseballs, boulders rolling downhill, planets in orbits, gives ridiculous results. Try it sometime. Calculate, for example, the de Broglie wavelength of a bowling ball thrown down an alley. Assume a normal bowling ball of 4 kg, and a velocity of 1.5 meters/second. You'll never be able to detect that wavelength. You're better off using Newtonian mechanics.
Yet, they existed.
The probability of such a wave occurring is a higher order problem than is readily dealt with through mere reference to calculus. First, you have to believe they exist