The concept of white horses emerging from the sea is an ancient one. In fact, a “White Horse” is another name for a white cap. In this case, the wave looks a lot like a horse jumping over the Cobb Wall at Lyme Regis in Dorset. This was published in the Daily Mail as an example of the flooding currently going on in the U.K. Just think, in the U.S. it would be frozen!
One of the most enduring images of white horses coming from the sea is this painting, Neptune’s Horses, by Walter Crane, painted in 1893.
And more recently (2007) there was a famous ad for Guinness that borrowed from this imagery.