Cortes Bank: the Largest Wave on the Planet

Surfer Mike Parsons drops into a huge wave, estimated at 70 ft, at Cortes Bank off the coast of San Clemente, California in 2008. Photo: Robert Brown/Billabong XXL.com.

…Dawn’s early light revealed a shimmering plume of spray. A Himalayan peak rose to life far off the bow. It was shaped like a great, volcanic cone– 43 million pounds of water, terrible and unrideable. Its foam exploding an unknowable number of feet into the air and churned the surrounding water into a 360-degree maelstrom of confusion.

— Chris Dixon (2011) Ghost Wave: the Discovery of Cortes Bank and the Biggest Wave on Earth.

In the annals of big wave surfing the torch for the largest wave has been passed many times: Makaha, Waimea Bay, Jaws, Mavericks’s, Outer Log Cabins, Todos Santos, Nazaré. But one surf spot stands alone: Cortes Bank. Located 100 miles off the southern California coast, Cortes Bank is as much legend as surf spot. A wave like no other. Not a coastal break but a swell that breaks on a submarine island. A titanic wave unloading on a submerged shoal in the middle of the ocean. The wave starts and ends in water deeper than 1,000 feet. And although the record for the largest wave ever ridden may not currently belong to Cortes Bank, it has the potential to hold a monstrous swell and create the largest wave on the planet, by far. Then, of course there is the human element: someone has to have the courage to ride it. So far, and amazingly so, surfers have met that challenge.

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Cortes Bank from the air. Photo by Flame/A-Frame, jeff@aframephoto.com.

To get there you have to imagine riding in a boat for many, many hours; far offshore, past Santa Catalina, past San Clemente, another forty miles out into the open ocean, to a place where an island used to exist in the past. 10,000 years ago it was called Kinkipar by native Americans, the ancestors of the Tongva or Chumash Tribes in southern California. In the present time, due to sea level rise, it is entirely submerged, the top rising to within 3-6 feet of the surface with nearby shoals catching the largest swells on the planet from the North Pacific. Monster swells that generate waves moving at incredibly high speeds as they move from the deep ocean, over a mile deep at the base of the bank, into a series of shallow reefs made of sandstone and volcanic basalt. Because of its location, estimates are that the waves are moving 50% faster than comparable waves along Oahu’s north shore. They are arguably the largest and fastest waves on Earth. As Bill Sharp remarked after the first time it was surfed in 1990 “It was like something out of Waterworld.”

Ghost Wave BookAlthough it was likely known by native Americans, it was “discovered” to the western world by James Alden, the skipper of the steamship SS Cortes, as he observed massive eruptions of white water in the middle of the deep ocean while passing by the bank in 1853. Soundings revealed a series of stair-steps 50 to 100 feet high from periods of previous sea level rises down to 400 foot depths that descend to the abyssal plains around the bank. Since then, and likely before, Cortes Bank has been the site of a few ship sinkings and many close calls, including the grounding of the 1123 foot USS Enterprise in 1985. In an absolutely gripping book, Ghost Wave, Chris Dixon describes both the history of Cortes Bank and the quest to explore and surf waves. This history includes the deliberate sinking of the 334 foot SS Jalisco to attempt to create the nation of Abalonia and the multiple quests to ride the waves over a twenty-year period beginning in 1990.

Reading Dixon’s book I was particularly fascinated by two aspects of his story. One, I was struck by the incredible courage of those that journeyed to the bank to ride the huge but largely unknown waves. Greg Long, for example, almost died there in 2012, yet returned in 2014 to ride the place — solo. Facing challenges like that are extraordinary and illustrate an uncommon ability to face possible death with the physical preparedness that installs a unique confidence among professional surfers. Second, I was fascinated by the potential of Cortes Bank to hold the largest swell on the planet.

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NOAA Nautical chart showing the location of Cortes Bank off southern California.

Cortes Panel

Close-up of NOAA Nautical chart (left) of Cortes Bank next to (right) color-shaded map of the bank illustrating topography Source: Seafloor Mapping Lab, CSU Monterey Bay.

Cortes Bank’s location and shape both contribute to its unique ability to converge and focus wave energy from the North Pacific. Located far from shore, the bank can capture swells before they slow down in shallow water on the coast’s continental shelves. More importantly, the shape of the bank, trending from NW to SE, captures and focuses wave energy along the length of the bank’s gradual stair-steeping shoal, channeling the energy into the shallowest areas around Bishop Rock. In addition, there is a thumb-like rock shoal (the “hook”) that bends and focuses additional wave energy into the area.  As described by Chris Dixon (2011) in his book:

[There] the wave would rise higher and higher in the shallows until reaching the final big stair step. There it would trip up, careening and falling forward like an enraged giant while peeling down the shallow water line like a a line of toppling dominos.

Given the bathymetry, a 15-ft, 20-s period wave could easily grow to 4-5 times its height creating a 60-75 ft wave (Dixon, 2011). In a big swell, a perfectly shaped 100 ft wave could be generated; during a once-in-a-century El Niño-type swell, a 1,000 ft wave is possible. All the other big wave spots, such as Jaws, Maverick’s and Todos Santos, begin closing out at 50-100 ft heights into a huge, unrideable wave.

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Wave convergence at Cortes Bank. As the swells approach the bank the shoal focuses the wave energy onto the shallow reef, greatly increasing the amount of energy, and size, of the wave. Source: Dixon (2011) based on an illustration from Sean Collins.

As to the question of whether a surfer could ride a wave that size, the jury is still out. It may be simply too fast and too big for someone to actually ride it. Of course, surfers have been down that road before: that’s what they said about Waimea Bay for years before anyone surfed it in 1957. The truth is that there appears to be no limits to the courage of surfers, whether they can survive a wave that size or not.

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  3 comments for “Cortes Bank: the Largest Wave on the Planet

  1. Donna Brown
    January 26, 2016 at 8:09 pm

    Hi Brian, This was so timely. I am talking about the sea floor this week in Oceanography class. I was just talking about this yesterday. Cool stuff. I love your blog! Aloha, Donna

    • January 26, 2016 at 9:19 pm

      Thanks Donna. This is fun and I’m glad it is useful. Lots more to come!

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