Why is Nazaré the biggest waves in the world?
There is a place in the world from which they often make photos and video reports about giant waves. The past few years, records in Big Wave surfing on the largest wave taken (both by hand and with a jet) are set on the same Nazare wave. The first such record was set by Hawaiian surfer Garrett McNamara in 2011 - the wave height was 24 meters. Then, in 2013, he broke his record by driving a wave 30 meters high.
Why is it in this place the biggest waves in the world?
Let's first recall the wave formation mechanism:
So, everything starts far away in the ocean, where strong winds blow and storms rage. As we know from the school course of geography, the wind blows from an area with increased pressure to a lower area. In the ocean, these areas are separated by many kilometers, so the wind blows over a very large area of the ocean, transferring some of its energy to water due to friction. Where this happens, the ocean is more like a bubbling soup - have you ever seen a storm at sea? Here there is also about, only the scale is larger.There are small and big waves, all mixed up, superimposed on each other. However, the energy of water also does not stand still, but moves in a certain direction.
Due to the fact that the ocean is very, very large, and the waves of different sizes move at different speeds, as the whole boiling porridge reaches the shore, it “sifts”, some small waves add up with others into large ones, while others are mutually are destroyed. As a result, what is called Groung Swell comes to the shore - even ridges of waves, divided into sets from three to nine with large intervals of calm between them.
However, not everyone swells destined to become waves for surfing. Although it is more correct to say - not everywhere. In order for a wave to be caught, it must collapse in a certain way. The formation of a wave for surfing depends on the structure of the bottom in the coastal zone. The ocean is very deep, so the mass of water moves evenly, but as it approaches the coast, the depth begins to decrease, and the water that moves closer to the bottom, for lack of another outlet, begins to rise to the surface, thus raising the waves. In the place where the depth, or rather the small fry, reaches a critical value, the rising wave can no longer become larger and collapses.The place where this happens is called a lineup, and surfers sit there waiting for a suitable wave.
The shape of the wave directly depends on the shape of the bottom: the sharper it becomes shallow, the sharper the wave. Usually the harshest and even breaking waves are born where the elevation difference is almost instantaneous, for example, a huge rock at the bottom or the beginning of a reef plateau.
Where the drop is gradual, and the bottom is sandy, the waves are gentler and slower. Such waves are best suited for learning to surf, so all surf schools conduct their first lessons for beginners on sandy beaches.
Of course, there are other factors that affect the waves, for example, the same wind: it can improve or degrade the quality of the waves, depending on the direction. In addition, there are so-called wind swells, these are waves that do not have time to "sift" distance, as the storm rages not so far from the coast.
So, now about the highest waves. Thanks to the winds accumulated huge energy, which then moves towards the coast. As the coast approaches, the oceanic swell transforms into waves, but unlike other places on our planet, it is a surprise off the coast of Portugal.
The thing is that it is in the area of the city of Nazaré that the seabed is a huge canyon with a depth of 5,000 meters and a length of 230 kilometers. This means that the oceanic swell does not undergo changes, but reaches, as it is, to the continent itself, falling on the coastal cliffs with all its might. Wave height is usually measured as the distance from the ridge to the base (where something like a hollow is often sucked in by the way, which increases the height compared to if measured by the mean sea level at a given height of the tide).
However, unlike waves such as Mavericks or Teahupu, on Nazare the crest, even if it collapses, never hangs over the base, moreover, it is separated from the lowest point by about 40 meters along the horizontal axis. Because of the spatial distortion of the perspective, when viewed from the front we see a water block of 30 meters, technically, it is even larger, but this is not the height of the wave. That is, strictly speaking, Nazaré is not a wave, but a mountain of water, pure oceanic swell, powerful and unpredictable.
However, the fact that Nazaré is not exactly a wave does not make this spot any less scary and dangerous.Garrett McNamara says that driving on Nazare is incredibly difficult. Usually three people help him in the water: one pulls him out on a jet to the lineup, accelerates him into a wave and does not swim away far enough to make sure that everything is in order with the surfer. He is secured by the second jet, as well as the third a little distance away, whose driver oversees all three. Also, Garrett's wife is standing near the lighthouse on the rock and tells him on the radio what waves are coming and which one can be taken. On the day he set his second record, not everything went smoothly. The first driver was hit by a jet with a wave, so the second one was pulled out of Garrett's foam, and the third one hurried to help the first one. Everything was done clearly and quickly, so no one was hurt.
Garrett himself says the following: “Of course, all these safety nets and technical devices in surfing on big waves are a kind of cheating. And in principle, you can do without them, but in this case, the chances of dying are much higher. As for me personally, since I got a wife and children, I feel more responsibility for them and fear for my life, so I go to all the technical tricks to be most likely to return home alive. ”