Deep beneath the Pacific’s surface, the world’s tallest waves have been discovered. Reaching up to 800 feet, the waves are known to researchers as internal waves. And you thought Garrett McNamara’s bomb at Nazaré was big.
Almost three miles beneath the ocean’s surface, internal waves are formed at the boundary of layers of water with different densities in a deep South Pacific trench, known as the Samoan Passage. These giant waves rise up due to ridges on the ocean floor in a narrow channel to the northwest of Samoa where cold, saltier water rises up into the warmer water above then plunges back down into the denser water on the other side of the ridge.
The findings are published in a journal named Geophysical Research Letters where Professor Matthew Alford says, “the flow accelerates substantially at the primary sill within the passage, reaching speeds as great as 0.55 m s−1. A strong hydraulic response is seen, with layers first rising to clear the sill and then plunging hundreds of meters downward.”
Although it will never (we can safely assume) be possible for surfers to ride these waves, they do play a much more important role. Scientists say that the waves are essential for mixing nutrients in the ocean. “Oceanographers used to talk about the so-called ‘dark mixing’ problem, where they knew that there should be a certain amount of turbulence in the deep ocean, and yet every time they made a measurement they observed a tenth of that,” said Alford in an interview with The Telegraph.
As the dense bottom layer of water flows over two consecutive ridges in the Samoan Passage, it forms waves, similar to air rising over a mountain. On reaching the lighter, warmer water above, they become unstable and break, mixing the two layers of water. The waves may also play a role in stimulating global currents teaching us that the seasonal swells we enjoy at our local breaks aren’t an annual coincidence.