California’s Biggest Waves: the Story of Cortes Bank (15 points)

What is Southern California’s iconic sport? Why surfing, of course! Where else but Southern California would have the first official World Surfing Reserve (at Malibu). Waves in Southern California are usually modest in size, and thus ride-able for surfers of wide-ranging talent levels. That’s because the islands and seamounts offshore here usually dampen swells arriving from the open Pacific. By the time the waves break on the Southern California mainland, they have usually become more “user-friendly” than waves to the north, in central or northern California. (Think back to the great waves at Mavericks which you explored in a previous assignment.)

This means that, if you want to see truly colossal waves in Southern California, you have to leave the mainland and head west, past the islands. The best place to go is Cortes Bank—home to some of the largest surf-able waves on Earth. What is it about Cortes Bank that can make the waves so big there?

Mike Parsons surfing one of the largest waves ever ridden, Cortes Bank, January, 2008. Rob Brown photo.

To find out, click this link to read Southern California’s Biggest Waves—the Story of Cortes Bank, excerpted from my book Surf, Sand, and Stone: How Waves, Earthquakes, and Other Forces Shape the Southern California Coast (published by the University of California Press).

Questions (please label your answers):

1.  Wind, waves, and the Pacific Ocean (5 points).

1a. What three wind-related factors control the size of ocean waves?  

1b. How does your answer above relate to why the Pacific Ocean hosts so many great surf sites?

1c. Where do most of the surfing waves that form in the Pacific come from, and at what times of year? (Hint: it’s all about where and when storms form.) 

1d. As the wind from a storm puts more and more energy into the ocean, how do waves change? (Be specific; there are four factors.) 

2.  Waves at Cortes Bank (5 points).

The biggest waves at Cortes Bank form when long-period swells (T = 20 seconds or more) approach from the northwest.  Explain why.  To do that, you’ll need to explain two things: 1) How the alignment (elongate orientation) of Cortes Bank relates to the wave direction, and 2) how and why the amount of refraction changes with increasing wave period and wave base.  (Hint: read the information in the section Getting to the Bottom of a Great Wave, and relate what you learn there to Figure 6 in the excerpt.)

3.  Catch your own ride (5 points)!

Here’s a chance to take a break from factual science and do some creative writing. Imagine that you are a world-class surfer on a big day at Cortes Bank.  Describe your experience catching a 60-footer from the moment your jet-ski partner tows you into the wave.  Do you “make it,” or do you fall and experience the terror of a “hold-down”?  Whatever happens, make your description vivid and immediate; take the reader with you for the ride.  For inspiration, you might watch this video of Mike Parsons on Jaws (Peahi) in Maui, Hawaii.  (It’s not Cortes Bank, but the wave is much the same.) 

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As always, please keep in mind my plagiarism policy.