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Extreme Waves 5 Swell If you drive along the California coast, you will often see the backs of figures in wet suits seated on surfboards, looking out to sea for the “perfect wave.” This same scene can be observed on any given day on coastlines throughout the world. What is it that brings these athletes to the fringes of the world’s great oceans, often early in the morning, even on days when the weather is miserable? It used to be that someone in the beachfront community passed the word—surf’s up—and chores or jobs were set aside in a race to get into the water and claim a good spot to catch a wave. Today, “surf’s up” is more likely to come from the Internet, where dedicated surfers can use their web browsers to navigate to a web site that provides not only the latest marine weather forecasts—including expected wave heights and periods—but also real-time data from ocean buoys thousands of miles away and even from video cameras that scan favorite beaches so a surfer can see what the waves look like without first driving to the beach. Surfing information on Internet sites helps surfers keep track of distant storms, use ocean buoy data to track the height and movement of waves, and use wave propagation models to predict when waves from
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Extreme Waves a recent storm in the North Pacific will finally reach shore in Newport Beach, California; Hawaii’s North Shore; Mexico; or Tahiti as the long, undulating waves known as swell. SWELL Just what is swell? As I explain in Chapter 4, storm winds typically follow a circular path, stirring up the sea as the storm propagates. Storm waves mix with preexisting sea waves, and in a short time the sea roils with a mixture of waves large and small, with long and short wavelengths, coming from various directions. This scenario is known as a confused sea. (See Chapter 7 for more on this subject.) Waves radiate from the storm center, in much the same manner as they emanate from a rock tossed into a quiet pond. Some of the waves will head off in the direction in which the storm is moving, in which case, if the storm continues to blow, they will grow larger. Others, headed in the opposite direction, will not increase in size. In either case, storm-generated waves propagate from the center of the storm, the faster waves (those with longer periods and wavelengths) gradually outstripping their slower counterparts. In this process, known as dispersion, the sea acts as a filter so that at locations distant from the source, the waves that traverse a particular point eventually will exhibit similar characteristics. These distant, dispersed waves are known as swell. (Later, when the slower waves reach this same point, their characteristics will be different.) Swell travels long distances, only slowly giving up its energy. Swell from a given North Pacific storm can be tracked clear across the Pacific until it finally dissipates on the coast of North America. Often the yachtsman will note that swell does not consist of nice uniform waves, but instead has a set of waves that seems to come at one angle to his course and another set that comes at a different angle. When swells from two different sources interact, the two (or more) wave fronts can produce various patterns. For example, two swell wave fronts intersecting at 45 degrees would produce a diamond-shaped pattern of crests and troughs. There can be more than two swells interacting—for example, near islands where swell impinges on the shore and reflects or is refracted back into the sea. If two sets of swell meet at
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Extreme Waves right angles, a checkerboard pattern is produced by interference of the individual wave trains. It is not unusual to encounter wave conditions that are a mixture of swell with superimposed wind waves. In these cases there is no standard pattern to wave crests and troughs, and this also can be called a “confused sea.” Swell eventually sorts itself out into one regular pattern of waves, trough following crest in an endless roll across the open ocean until land is reached. In this process, swell loses very little energy until shallower water is reached and the waves begin breaking. As it crosses the ocean, if it encounters favorable winds, swell can grow in height. I can recall standing on the beach on idyllic summer days and looking out to sea at the seemingly endless progression of waves rolling in, swell generated by some distant Pacific storm. Surfers call this a corduroy sea, the term inspired by the distant blue-green ridges of water. When body surfing—that is, without a board—I looked for waves big enough to give me a good ride but not so big that it was impossible to swim out to them or so big that they would grind me into the sand if I caught them at the wrong time. LARGE SWELLS Historically, certain years stand out as years of giant swells in the Pacific—1953, 1969, 1983, and 2001, for example.1 Of these, the swell of 1969 is perhaps the most notable. In late November 1969, a large storm started building in the North Pacific Ocean, near the Kamchatka Peninsula. Moving east, it combined with another storm and increased in size to the point at which winds greater than 50 knots were blowing along a 1,700-nautical-mile front reaching from north of Hawaii to the Aleutian Islands. Then it stopped and remained stationary for a day and was joined by a third storm. With high winds, lengthy duration, and a fetch of thousands of miles, it is no surprise that huge waves were produced. On the first of December, 30-foot-high waves hit the northern island of Kauai; hours later, Oahu’s North Shore was hit by waves up to 50 feet in height. Some areas were evacuated, homes were destroyed or badly damaged, coastal highways were flooded, and several people were
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Extreme Waves caught in waves and drowned. Four days later the big waves reached Southern California, where there was a similar pattern of beachfront damage, flooding, and several deaths. In the midst of all of this chaos, a few highly skilled surfers rode waves in the 18- to 35-foot class, among the highest ever ridden up until that time. Most beachgoers just stood on the shore and stared at the huge waves as they came crashing ashore. Another big swell came in 1983. More than 1,000 structures along the Southern California coast, including piers in Oceanside, Seal Beach, Redondo Beach, and Santa Monica were damaged by the waves; about one-third of the Santa Monica pier was lost to the sea. It was the swell of 1983 that saw the inauguration of big wave surfing. SURFING Board surfers live for those magical days when a large swell builds along the coast from distant storms and the perfect ride seems attainable. Those who live close to the beach can walk or drive to their favorite spot and look at the line of waves rolling in to decide if it is worth it to unlimber their boards and put on their wet suits. Others, like my son Kent Smith, a biochemical research scientist for Mannkind Corporation, access web sites such as www.surfline.com, where they can see the latest projections of surf conditions, even being able to see the waves in real-time cameras mounted at the most popular sites. It is also possible to access weather buoys located along the coast and in the ocean, to check wave heights and periods, and to track the likely progression of different storms. Is the swell building or dying? A good storm might create conditions that last several days. When the waves first reach the coast, they will be building and sets will come closer together as the day progresses. Later, once the effects of the storm begin to dissipate, the wave energy starts decreasing and sets are spaced farther and farther apart, leaving the surfers to sit motionless on their boards, scanning the horizon for a sign that another wave is coming. Surfers have their own lexicon for describing wave heights and extreme waves, comparing them to their height when standing on their boards. A waist-high wave is hardly worth getting suited up for, unless the beach is uncrowded and other conditions are perfect. Head-high
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Extreme Waves waves draw surfers like a magnet to the best spots; when the waves are said to be “overhead,” the less hardy begin to drop out. “Double-overhead” waves represent a cutoff point; a 20-year veteran like Kent would surf if conditions were perfect, but would exercise caution on a stormy day when the seas were uncertain. When you read of the surfers in Hawaii who ride 25- to 35-foot waves, you begin to get a real appreciation for the skill and risk that are involved. And a 68-foot wave, as described later in this chapter, is something else, totally out of the league, akin to climbing Mount Everest without oxygen.2 It is not just the height of waves that matters as they come rolling in from storms in the distant reaches of the Pacific, but how they impinge on the shore. Surfers describe beach breaks, point breaks, or reef breaks. A point break is where the incoming swell is refracted by a point of land, a cape, or even a man-made jetty. In Southern California, locations where point breaks occur have descriptive names: “Trestles,” “Rincon,” or the “Wedge.” When conditions are right, point breaks give long, exhilarating rides. By catching the wave as it starts to break near the point, the surfer is able to ride the cresting wave in a direction parallel to the beach for a long distance. When the surf is high, one of the challenges is getting to it. With a point break, surfers can usually paddle their boards around the outside of the break and catch the next wave. At a beach break—as at Huntington Beach or Black’s Beach near San Diego—surfers ride the waves into shore and then paddle back out through the surf to catch the next wave. This becomes a challenge with large waves—you somehow have to fight your way through them to get back out for the next ride or paddle out around the break. Sometimes the outgoing current is channeled in such a way that it facilitates the ride back out. Wind plays into the equation as well. Surfing in a storm—in chaotic seas stirred up by the wind—is not enjoyable. Neither is a strong onshore wind, because it tends to flatten the waves and reduce their height. In Southern California there are many days when the land heats up, there is a high-pressure area inland, and winds blow offshore, a condition locally referred to as Santa Ana winds. This is highly desirable, not only because it usually heralds a warm day at the beach but also because the wind tends to blow against the front face of the in-
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Extreme Waves coming waves and hold them up so that they don’t break, or take longer to break. When a large wave breaks over a shallow area, such as a reef or sandbar, the bottom of the wave is slowed and momentum carries the top of the breaking wave forward so that it curls over and creates a hollow tunnel, called a tube in surfing jargon. A strong Santa Ana wind also helps form a tube because the wind lifts and supports the crest as it starts to fall. Good, rideable tubes occur infrequently, but when they do, a spectacular image is created when the surfer disappears behind a huge waterfall of seawater and emerges unscathed a few seconds later at the other end—surfing nirvana, you could say. Reef breaks as in Hawaii and other island chains present opportunities for really large waves—say, double or triple overhead—but conditions must be considered carefully. First, the tide must be just right. Too low, and the waves might break on the reef itself, presenting the potential for serious injury to the careless surfer. Too high, and waves pass over the reef without breaking. When conditions are right, waves coming in from deep water pile up as they reach the reef, creating the long and impressive tube rides seen in surfing movies during which the rider seems to be traversing a long tube of water, the sea towering over his or her head. How about a simulated reef break in midocean? There are instances in which a rogue wave has suddenly risen up out of the water and struck a ship broadside. The result is most likely a capsize, unless the vessel manages to recover from the roll. If a wave rose up in front of a vessel and hit the bridge, the effect would be quite different. The force of the water is so great that it can shatter the thick glass of the pilothouse windows, and there have been cases in which the wave washed the helmsman off the bridge or tore the bridge off the vessel. In other cases, plowing bow-first into a huge wave, vessels weighing thousands of tons come to a nearly complete stop, the impact causing the steel vessels to shudder over their entire length. I cannot imagine anything more terrifying than being on the bridge of a large vessel at night when something like this happens. Yet there are other brave souls who deliberately confront such giant waves on surfboards.
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Extreme Waves EXTREME SURFING These daredevils are members of a very select group of world-class surfers who use personal watercraft—wave runners—to haul surfers out to catch a giant wave and then recover the surfer after the ride. When the waves are extreme, they are moving so fast that it becomes impossible to catch them by paddling into them by hand on a surfboard. Instead, surfers are towed into the wave and released. I thought it would be useful to talk to some of the best of these extreme wave surfers, and see what I could learn about the behavior of giant waves from people who have experienced them up close—who have an intimate knowledge of them. Cortes Banks, described earlier, is in the category of a reef break. When winter storms create 50- to 100-foot-high waves, surfers must first make a 100-nautical-mile boat ride just to get to the site. Once at the site, they are towed into position by wave runners racing at speeds of around 40 miles per hour. After the ride, the wave runner circles back, retrieves the surfer, and takes him or her out of harm’s way—assuming he or she survived the ride. Mike Parsons is a Californian who surfed the big winter swell in 2001 at Cortes Bank, riding a wave estimated to be 60 feet high.3 There are other spots where surfers go to seek big waves—in Northern California, Australia, South America, and of course, the North Shore of Oahu, Hawaii. In February 1986, several surfers rented a beach house on the north shore at Ke Iki. The swells were running 15 to 25 feet with occasional waves to 35 feet. At midnight on February 22, a giant wave hit the beach, threw cars across Kamehameha Highway, and destroyed four houses. Bruce Jenkins and Rich Stevens were sleeping in one of the houses; Rich literally surfed out of the house on a mattress when the wave blew the house apart, ending up in a parking lot 50 feet away. Bruce was trapped momentarily under his bed, but managed to work himself free. Later, eyewitnesses estimated the size of the wave at around 60 feet.4 When the last El Niño hit, winter swells were massive in Hawaii. On January 28, 1998, surfer Ken Bradshaw was towed out into the huge surf at a spot called Log Cabins (outside the reef at Waimea Bay), where he successfully caught, rode, and survived a wave that was estimated to
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Extreme Waves be 80 feet high. Dan Moore—also a surfer—was there to see it, and I asked Dan if he thought that it was the largest wave anyone had ever ridden. “Ken and I were partners,” Dan said. “We surfed together for a number of years. In fact, he was the one who got me interested in towsurfing. That day at Log Cabins was incredible. They were some of the biggest waves I’d ever seen. Ken caught one that was just unbelievable. As for anybody riding something bigger than that, I don’t know, maybe at Jaws (Pe’ahi, Maui) on January 10, 2004, when Laird Hamilton caught a monster wave; it could have been bigger.” This is a dangerous sport; the celebrated surfer Mark Foo drowned in Northern California in surf with smaller waves. Mark was a consummate, experienced surfer, renowned for his unique and graceful style. His tragic death is a reminder of just how vicious the sea can be, even to the most skilled surfers. Others have suffered broken backs, broken necks, and other injuries after being driven into the sandy bottom or, worse yet, a coral reef. TRACKING BIG SWELLS Figure 9 in Chapter 3 is familiar to all boaters—a National Weather Service wind-wave forecast for March 7, 2005.5 Note the storm building in the Northeast Pacific with 42-foot-high waves centered at 150 degrees west longitude, 40 degrees north latitude. By coincidence I happened to save this particular forecast as I was writing this chapter. Several days later, Kent Smith, whom I’d consulted on technical questions regarding surfing, called to say that a large swell was impacting the coast at Ventura, California, where he lives. Waves were expected to reach 13 to 16 feet. The Los Angeles Times published an article describing big waves and the possibility of flooding in low-lying coastal areas.6 The storm had initially been around 1,500 nautical miles from Ventura. When I looked at the wind-wave forecast for March 10, the storm had moved northeast and was close to Valdez, in the Gulf of Alaska. The distance was now about 1,700 nautical miles. Thus, the swells originating in this storm took 72 hours, traveling at 24 knots, to reach the beaches at Ventura.
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Extreme Waves There are a number of sources for wave information. One of the best is a U.S. Navy web site, commonly referred to as the “WAM” site.7 Plate 8 shows a WAM forecast for April 16, 2005, at 0 hours “Zulu” (Greenwich) time. The biggest waves—36 feet—can be seen at latitude 60 degrees south, off the coast of Antarctica, propagating north past Madagascar, in the opposite direction of the Agulhas Current, but no big waves are indicated in this region in the forecast. The National Oceanic and Atmospheric Administration, as well as Canada, the Scripps Institute of Oceanography, and other entities operate a series of buoys in the Northwest Pacific and California coastal areas. These also can be accessed using the Internet. I did this for buoy 46006, which bears the name of “SE PAPA.” It is a fixed buoy located 600 nautical miles west of Eureka, California. I could see a clear pattern of the wind speed building to 29 knots on March 7, 2005, with gusts to 35 knots, a significant wave height of 16.4 feet, and a period of 14.3 seconds. On March 10, 2005, the buoy at Goleta Point, California, was showing the predominant swell arriving from the west (around 260 degrees), with a dominant period of 18 seconds and a significant wave height of 9 feet. Here again, the height was steadily building. Farther south, near La Jolla, California, a site predicted rising surf on March 9 and 10, possibly 10- to 14-foot wave faces. For March 10, the forecast concluded with a final note: Proceed with caution. RIDING EXTREME WAVES Farther north, at Monterey, California, near the famed Pebble Beach golf course, “proceed with caution” was the watchword for the day on March 9 at a little-known surf break called “Ghost Tree,” at Pescadero Point. Here, surfing contestants were competing in an event called the annual Billabong™ XXL Global Big Wave Awards. The idea of the contest is to search around the world for the biggest wave you can find, ride it without killing yourself, get someone to take a picture to prove you did it, and get paid $1,000 per foot of wave height if you survive and are a winner. Among the finalists, several had already ridden big waves at “Jaws,” a spot for big waves at Pe’ahi on the island of Maui, Hawaii. Previous winners have ridden waves at Mavericks, located near
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Extreme Waves Half Moon Bay, California, or have chased giant winter swells at Cortes Bank. The March 7 storm described above was cooperating nicely with the competition. Monterey was about 165 nautical miles closer to the storm and faced directly into the waves, not sheltered behind Point Conception as was Ventura. By March 9, waves with faces of 60 feet or more were crashing on the shoreline with such violence that golfers on the nearby golf course stopped to watch. By the end of the day, the score was Ghost Tree 2, surfers 2. One surfer sustained a shoulder injury, and he and his rescuer had to be rescued; another broke his leg in four places. Two men managed to ride the largest waves and made it to the group of five prize money finalists. However, the winner turned out to be Dan Moore, credited with riding a 68-foot-high wave at Jaws (Pe’ahi, Maui). (See Plate 1.) The previous winner was Pete Cabrinha, who received $70,000 for his world record ride on a 70-foot-high wave in 2004. When I spoke with Dan, I asked him how it felt to ride a fiberglass board 6 feet long weighing about 10 pounds in the presence of huge waves that were known to break the backs of supertankers and container ships built of steel and weighing thousands of tons. He described it as exhilarating, an adrenaline rush. “It is a remarkable experience, just entering the wave; it is an entirely new environment that nothing can quite prepare you for—the wind blowing, hurling salt spray in your face, partially blinded, being hammered by jets of water. Just negotiating the chop to get into position you take a beating, a lot of shock absorption. It looks easy, but the average person, without training and conditioning, could not deal with this. Then the release, and you are racing down the face. It looks smooth, but it is actually a bumpy, jarring ride, until you get to the trough; there it smooths out. “While it seems longer, the entire ride is over in about 45 seconds. “You really have to rely on your partner to get you into the wave and then get you out. Mark Anderson drove for me at Jaws. He has years of judgment, of being on the water watching waves, and is able to anticipate what the wave will do. You have to know where the wave is going, know how the wave runner is traveling at 20 to 30 miles per
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Extreme Waves hour, where the wave will be when the wave runner comes from behind to catch it, and finally you have to correctly judge the moment of encounter to put the surfer on the tow rope exactly at the ‘sweet spot.’ Timing is critical at the point of release. There is kind of a whipping action. The tow rope slings you into the wave; you accelerate up to 35 miles per hour. You have to enter the wave just as it starts to get steep—not too early, not too late—at a high enough position to be able to run down the face as it curls over behind you and yet still be able to get out of the way before it buries you. “Your partner hangs back behind the wave, looks for you to come out, or if you crash, looks for you to pop up, then races in to get you on the sled and get out of there before the next wave breaks. On this wave, my board didn’t release properly and I ended up fracturing my ankle. I got hit by another wave and then somebody came in and got me out. “Timing is important with the wave runner also—blow it, get caught by a wave, and you can kiss it goodbye. Last season I think there were five that got creamed, ended up on the rocks. That’s $10,000 each. Then, to add insult to injury, you have to hire a helicopter at $700 to come pick it off the rocks. No littering the beach allowed!” I asked Dan about his worst wipeout. “Worst one—which time? As they say, you have to break a few eggs to make an omelet. I’ve had a lot of spills. That’s probably the only way you can learn. But I’d say on January 19, 2004, at Jaws, my first wave of the day was the most recent ‘memorable’ one. I went down in a bad way. I was on a new board; the wave was 20 to 25 feet high. I went into it and something happened to the board—maybe cavitation. I did an immediate face plant, then got sucked up over the falls. I was annihilated. It is hard to describe the violent motion that goes on inside a big wave. You have tons and tons of water pounding on you. When water hits at high speed, it is hard, very hard. It drives you down into caverns at the bottom of the ocean and then forces you back up under pressure. I don’t think I hit anything. It was just that the forces cause your brain to rattle around inside your skull. When I finally came up I was disoriented, seeing stars, dopey. I must have had a mild concussion. Two more waves dumped on me, until finally someone came in and got me out. I don’t remember much; I just saw a blur of motion, some-
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Extreme Waves body on a wave rider who yelled ‘raise your hand.’ I was so out of it I didn’t even know to raise my arm. He grabbed me and pulled me onto the sled. He took me to one of the photo boats nearby where I rested. It took me about an hour and half to recover. Then I grabbed my backup board and went back in and got another dozen rides or so, and one more wipeout. “This was just one of a number of memorable experiences, all part of the learning process.” TOWSURFING Dan and many of the other extreme wave surfers belong to the nonprofit Association of Professional Towsurfers. I spoke with Eric Akiskalian, a cofounder and current president of the association, about what it took to excel in this dangerous and demanding sport. He told me how surfing emerged as a new sport when surfers began pursuing ever-larger waves, using such personal watercraft as the Yamaha High Output that has a 160-horsepower engine, can carry one to three riders, and can travel at speeds up to 60 miles per hour. He remarked that the main qualities are training and physical conditioning, adding that the ability to read the waves and anticipate their behavior is very important, but always expect the unexpected. Akiskalian grew up in Santa Barbara, California, and has been surfing abroad for more than 35 years. (In addition to cofounding the towsurfers association, he created an extreme surf web site, www.towsurfer.com.) I asked Eric to give me some background on towsurfing and how it got started. “With the inherent dangers involved and the ever-growing interest in extreme sports, tow-in surfing has become one of the most exciting competitive water sports in the world. It didn’t happen overnight; it began as an experiment by Laird Hamilton and some other Hawaiian surfers, including Buzzy Kerbox and Derrick Doerner. They were the first to take an inflatable Zodiac raft with a 40-horsepower motor out to a spot called Phantom’s on the north shore of Oahu in the early 1990s.” Their approach was simply to check it out, according to Eric. “They didn’t even tow that day. They just went out in the boat, looked around,
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Extreme Waves while dropping into a 15-footer that almost ran them over. It was a little creepy, and if they’d been caught and flipped with the engine blazing, it could have been nasty.” Eric told me that it was not until 1991, when Buzzy and Derrick made an attempt with a 60-horsepower Mercury Outboard, that they actually started to get the hang of a motor-assisted tow, like a waterskier or wakeboarder. It gave them a quick enough start so that they had the speed to glide down the giant open face of the wave after release. They got the idea of using a personal watercraft, or PWC, from these early experiments. The following year they brought their experiences and passion to Pe’ahi on Maui’s north shore (the spot called Jaws) to tow into surf even bigger and more powerful. “As it has evolved, tow-in surfing is an ocean-based sport that requires the use of a PWC, rescue sled, life vests, tow rope with handle, and two very experienced and passionate big wave surfers,” said Eric. “Drivers use the PWC, trailing a 30- to 40-foot-long rope and handle, to position their surfer in the right part of fast-moving ocean swells. When the surfer drops the rope, he uses his momentum to catch waves that can’t be caught by paddling. “Drivers monitor the position of their surfer at all times and place the PWC just behind the breaking wave to offer immediate assistance to a surfer who finishes or falls on each wave. Buoyant rescue sleds are attached to the back of each PWC, providing a stable platform for surfers to grab hold of and travel in and out of the wave lineup. “The surfer’s life depends on his partner’s ability to drive that PWC, assist in pickups, and come in for the intense rescue before the next mountain of water rolls over them. It is not uncommon for surfer, driver, and PWC to get plowed over by four or five building-size walls of whitewater. I should emphasize that tow-in surfing is a dangerous sport that requires a level of mental and physical conditioning that only year-round conditioning and training can provide. There has to be a bond and a high degree of confidence between the partners. Mental and physical preparation can include underwater rock training (holding or carrying a rock underwater to practice breath holding), swimming, weight training, and paddling, paddling, paddling—in short, everything to insure superb physical conditioning.”
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Extreme Waves So where are the top big wave spots in the world, I asked? Eric mentioned a handful of locations where big waves occur: Maui, Pe’ahi—Jaws Northern California—Mavericks Mexico—Todos Santos Southern California outer waters—Cortes Banks California central coast—Channel Islands Northern California, Monterey—Ghost Trees Tahiti—Teahupoo Oregon—Nelscott Reef Australia—Shipsterns Bluff France—Belherra Reef Chile Canada Africa—Dungeons I also asked Eric if there is an ultimate limit in the sport—if he thought that surfing a 100-foot-high wave is possible. “Of course,” he said. “Someone will do it. It is just a matter of finding the wave, being in the right place at the right time. If they can’t get towed in, they’ll drop from a helicopter or find another way, but someone will do it. Just like Mount Everest—once you knew it was there, someone had to climb it, even though you might get killed in the process.” LONG-PERIOD TRAVELERS The ability of swell to travel long distances was demonstrated dramatically to me in September 2005. Around September 8 or 9 an extratropical storm developed near New Zealand. I heard of this from my friend Ray Holdsworth, who had just returned from a cruise in Tahiti. During a stop in Bora Bora, he learned that on the night of Saturday, September 10, a large wave or waves had washed over the reef and damaged some resort buildings, resulting in an evacuation of guests in the early morning hours. A few days later the swell reached Hawaii and
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Extreme Waves created unusual surf conditions. Meanwhile the California newspaper surf reports were predicting that a big southerly swell would arrive eight days after the New Zealand storm on Friday and Saturday, September 16 and 17. Thursday, September 15, had a 6.5-foot-high tide forecasted at 8:00 P.M. for the Southern California coastal area, with the tide being slightly higher Friday night when the moon was at its perigee (closest approach to earth). Ironically, the arrival of a big swell coincided with one of the year’s highest high tides. At that same time, Bill Watkins, vice commodore of the California Yacht Club, along with other members of the club, had his boat on a mooring in Catalina Harbor. He told me that on Thursday night a large wave came into the harbor, rocked all the boats, and tossed dishes and other supplies onto the floor of one of them. This in itself was unusual, since Catalina Harbor is a deep protected cove where one rarely feels any boat movement at anchor or on a mooring. It was made more unusual by the fact that the wave also washed out a portion of the road leading to the California Yacht Club’s Ballast Point facility at the edge of the harbor or, as Watkins put it: “Just like you’d used a skiploader to cut a channel.” Around the same time Thursday evening, large waves crashing on shore broke windows in oceanfront homes at Malibu, California, and on Friday and Saturday surfers had 12- to 15-foot-high waves at Newport and other south-facing beaches in Southern California. Remarkable to think that waves generated by a storm in the southern hemisphere could retain their energy and travel 6,000 nautical miles at an average speed of around 31 knots and cause damage in the northern hemisphere on the opposite side of the Pacific Ocean! SWELLS IN MIDOCEAN One of the joys of being on the ocean on a good sailing day is sailing “down wind and down swell.” Under these conditions the boat moves smoothly, a slight heel, and the helmsman can feel a surge of speed as each swell passes under the stern of the boat and pushes it toward its destination, adding to the forward motion due to the wind. Looking
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Extreme Waves aft, the helmsman can see corduroy—an endless progression of waves coming from the horizon toward the vessel. Normally, because of its long wavelength, swell does not represent a hazard to oceangoing vessels. Even if the significant height is large, the vessel will ride up the wave front and slide gradually down the back side. However, if waves having a similar wavelength intersect, some crests can add, while others cancel out, and larger waves can be produced. This condition can give rise to extreme waves and is discussed in Chapter 8. Sometimes such large waves will break in midocean, creating new, shorter-wavelength waves. The helmsman, lulled into complacency by the endless succession of uneventful swell, will suddenly experience more dramatic action as the ship is tossed about by the shorter-period waves. A common remark muttered under these circumstances (as the galley crew picks the dishes up off the floor) is, “Where did that come from?” Today, satellite observations of the oceans are leading to improved understanding of swell patterns throughout the year. By using satellite-based altimeters to measure wave height and by making simultaneous satellite determinations of wind speed, global swell probability maps can be constructed. These maps indicate a northward trend in ocean swell patterns in the Pacific and Atlantic oceans. This is thought to be due to the northward propagation of strong swells produced by winter storms in the southern hemisphere during the austral winter. Meanwhile, the swells in the Indian Ocean tend to extend southward in spring and westward in winter, but diminish in area during the summer.8 Tod and Linda White, friends and neighbors of mine, sailed their 37-foot sailboat Seascape to Hawaii during the early summer, following a long, curving, westerly arc from 33.5 degrees to 20.5 degrees north latitude. Encountering nearly perfect weather, they made the 2,200-nautical-mile trip in just 16 days. Tod reminisced about standing watch one night when a 10-foot swell was running. “It was dark—just stars and a new moon, but enough light to make out the waves as they approached Seascape’s stern. I’d see a dark wall of water rise up higher than my head, if I’d been standing. It would block my view of the ocean behind us. Magically, the boat would rise up as
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Extreme Waves the wave swept under Seascape and passed us on its way, with nothing to note its passing other than the feeling of Seascape sliding down the rear of the wave to its former position, and a soft swishing sound as the wave flowed past the boat. Behind us, the sea glowed faintly in a trail of phosphorescent bubbles and then all was still until the next swell appeared. There was a special peacefulness to it, alone in the Pacific, far from land, the only sound being the boat’s movement through the water and the sensation of mile after mile sliding under the hull, wind and wave bringing us ever closer to landfall at Hana, Maui.” The long, smooth undulations of the sea are familiar to every sailor. Thus, on August 27, 1883, the captain of the vessel Evelina was not particularly concerned when he observed some large, smooth oscillations of the sea at his location near the Cargados Carajos Shoals, a remote speck of ocean reefs in the Indian Ocean several hundred nautical miles northeast of Mauritius, at latitude 17 degrees south and longitude 60 degrees east.9 The only thing surprising was that the sea beforehand had been calm, and this disturbance occurred shortly after noon. If the captain had been able to send a diver down, he would have noticed another curious fact: The water deep below the ship was moving, rather than being calm as it would have been in the case of a gentle surface swell. Later he would learn that 2,660 miles to the northeast, the island of Krakatoa had just blown itself to bits. Traveling at 320 knots, the tsunami wave had just passed under his ship.
Representative terms from entire chapter: