The physics of ocean waves are still difficult for existing science to fully explain.
For hundreds of years, reports of giant, 100-foot waves have been dismissed as nothing more than tall tales from the high seas. In her new book The Wave: In Pursuit of the Rogues, Freaks and Giants of the Ocean, award-winning Toronto-born journalist Susan Casey describes walls of water that defy the laws of physics. She spoke to The Globe and Mail about how these waves threaten global shipping, the role of climate change in their creation and why a breed of surfer actually seeks them out.
Until recently, scientists have said a 100-foot wave was impossible. Why did it take so long to confirm these things exist?
The ocean is very poorly understood and sparsely explored, really. It's a very complicated organism, and we're basically in kindergarten when it comes to understanding our own planet, particularly the oceans. There's a lot of chaotic, random things that happen in nature that don't conform to the rules that we've set.
Rogue waves operate outside the rules of physics and pop up in unlikely conditions. Do you feel like you understand how they are formed?
I can explain it in so far as science can explain it, but there are many circumstances under which science still can't explain them. They usually occur when the seas are very steep. As one scientist explained to me, steep waves are further away from equilibrium, they're less stable. So all of a sudden one wave will just sort of lose balance and grab the energy from three or four waves around it. It becomes three times as big but it's very unstable and it's more like an avalanche of water than a wave. It's kind of a mutant and it behaves in a very different manner. Normally a wave in an open ocean wouldn't break. These ones do.
Why do you and other people think it's important to understand these waves.
Because we use the oceans and lives will be lost, certainly in the shipping world, if we don't. If we want to live on coast lines, which we do - 60 per cent of the global population lives within 30 miles of the coastline - then we need to understand how the ocean works, period. And it's not just rogue waves: There are also tsunamis and surges like the one that caused Katrina.
Do you think people take the oceans seriously as a threat? I feel like the Asian tsunami and Katrina are regarded almost as flukes of nature.
It's really true. The average person was probably like "What's a tsunami?" But in 1755 … Lisbon was wiped off the map. That's not very long ago.We can't prevent it, but we can prepare. On the northwest coast of the United States, where there are some pretty jumpy fault lines and where big tsunamis have happened in the geological record, there are warning devices. There are devices on the sea floor. They used them last winter. People in Hawaii were told to get to high ground.
Some people see such warnings as good news. You spent time with a group of surfers who actively seek out these big waves
They remind me of the test pilots in The Right Stuff. They're surfers the way astronauts are pilots. They're more aware of the ocean's power than anybody. I don't think anybody's going "Yeehaw it's going to be a stormier world."
And yet they put themselves at huge risk by trying to surf these huge waves.
I think the body kicks out a very potent brew of chemicals when you do something that intense.
Knowing about these rogue waves, are you nervous about being in coastal regions?
I don't think I would buy low-lying land near the ocean. The water could get a little bit higher, it could also get a lot higher. You don't know. Uncertainty doesn't mean it's not happening. I don't think you can get out of bed in the morning and actively fear it, but it certainly doesn't hurt to respect it and learn about it. You're not going to outmuscle a 70-foot wave. We're not that powerful, even though we think we are.
How waves become monsters
Most waves are soothingly predictable. They are defined by wavelength (the distance between crests) and period (the same measurement in time), and created by a number of variables including the depth of the water, tidal forces, wind and ocean currents. In most conditions, one wave will be similar to the next. But rogue waves as high as 100 feet have been reported in 30-foot seas, with one wave behaving in a manner unlike those that surround it. The first official confirmation of such waves came in February, 2000, when the British research vessel RRS Discovery was trapped in the North Atlantic in a vortex of giant waves, including several approaching 100 feet. There are several theories about how this happens. Some believe that ocean currents can cause waves to "pile up" when waves run into currents head on. When big waves hit a strong current, it's like a car running into a brick wall, and they can grow unexpectedly and even break. But not all rogue waves occur in strong ocean currents. Another theory involves wave reinforcement, where multiple waves essentially combine their size. Once in awhile, several waves can come together and create a huge wave in relatively calm seas.
Is climate change a game-changer?
According to experts interviewed by Ms. Casey, storm tracks around the world are shifting and extreme weather is getting more extreme. This means that weather patterns are popping up where they're not expected: A tornado in Brazil, a hurricane north of Toronto. Around the world, the water levels are also rising. The global average sea level rose approximately 6.7 inches in the 20th century and hasn't stopped. In fact, some scientists say it will rise another six feet in the next hundred years. Combined, these factors increase the volatility of the oceans, which in turn can produce larger, and less predictable waves. Shorelines that were once protected by ice or coral reefs are now exposed as their natural barricades have melted or disappeared over time. Whether humans precipitated these changes, Ms. Casey believes the potential for disaster is growing: "Nine of the world's 10 largest cities are located on low-lying coastal land."
Riding giants
Monster waves don't fill everyone with fear. A group of pro-surfers in Hawaii, including Laird Hamilton, actually invented a new kind of sport specifically to tackle these giant swells. In the 1990s, tow-in surfing was developed to allow surfers to catch waves too big and fast to be accessed by paddling. This method involves a surfer being towed into a breaking wave by a partner driving a watercraft or even a helicopter. The technique has earned Mr. Laird a reputation for being the best of the big-wave surfers, as he has successfully survived the descent of waves as high as 70 feet.