Every surfer has heard about the biggest waves on the planet: the waves of Nazaré. These are considered colossal waves that have broken Guinness World Records for size. Beastly waves that every surfer dreams of riding. But why do these gigantic waves occur?
In this article we are going to tell you what the waves of Nazaré are and why they occur.
What are the waves of Nazaré
Nazaré is a very small but quite beautiful town, mainly inhabited by fishermen. It's located in the Portuguese part of the country, about 100 kilometers north of Lisbon. Until a few years ago, it was unknown to most people. However, today it's quite famous because it's home to some of the most gigantic waves that break right in front of its lighthouse.
It's not just famous among surfers, but also among all kinds of travelers and tourists unfamiliar with the sport. These are some of the biggest waves ever surfed, considered veritable mountains of water. Many people wonder why these kinds of waves occur in this particular spot. Let's explain it simply.
It's important to know that many waves form due to differences in depth within the ocean floor. We know that ocean currents are driven by wind and variations in water temperature and salinity. Therefore, when there are significant differences in depth between the continental shelf and the canyon, a flow of water creates large waves. If you'd like to learn more about this phenomenon, you can consult our section on waves.
The Nazaré Canyon is considered the deepest sea gorge on the entire European coast and one of the deepest in the world. It stretches for approximately 230 kilometers and reaches a depth of 5.000 meters . When a powerful WNW swell hits the Nazaré coast, a curious phenomenon occurs involving several factors: the swell, the continental shelf, and the coastal current. As a result, some of the world's largest waves are formed. If you are interested in learning more about wave formation, you can visit our page on Nazaré's giant waves, their formation, and characteristics.
Formation of the waves of Nazaré
When waves approach the shore of this town, they tend to grow rapidly due to two geomorphological factors. These factors, which are essentially the morphology of the surrounding seabed and wind speed, are what cause these giant waves to occur. To better explain this, let's imagine the Atlantic Ocean, being very deep, suddenly encountering a "step" that reduces the ocean's depth almost abruptly . This change in ocean depth causes the swell to compress and be projected upwards.
Furthermore, another factor that generates these giant waves is a current of water channeled along the coast from north to south. This same current flows in the direction of the incoming waves, further increasing their height. For an even greater effect, the backwash, also known as the water projected from the beach out to sea, adds several more meters to the height of the incoming waves. All these variables and circumstances have led to the waves of Nazaré holding a Guinness World Record for the largest waves ever surfed.
The formation of these giant waves can be described as a chain reaction. The first factor is the difference in depth across the marine morphology. Rocky areas and underwater mountains have varying orientations that create contrasts between the speed and depth of the incoming waves, causing a change in that depth. This difference in depth triggers an increase in wave height, and as the swell converges with the canyon, the local current intensifies. The final link in the chain is the backwash, which further increases the wave's level and height.
How are coastal waves predicted?
If you're a surfer who travels to different parts of the world to catch giant waves, predicting those waves becomes crucial. However, measuring waves in the open ocean is more difficult than it seems. This is because there are variations in the height recorded by buoys, making it impossible to distinguish each wave individually. All the buoys overlap, and the waves arrive from different directions. As a result, open ocean swells are measured using statistical patterns. That is, measurements are used to calculate averages for wave size.
In contrast, predicting wave height in coastal areas is a more straightforward process. Waves tend to follow a preferred direction as they approach land. The separation between individual waves is more clearly defined on the open sea coast. Therefore, it's easy to measure the size of the waves in Nazaré and estimate their exact height. This is achieved using mathematical models that consider parameters such as wind speed and direction . It also takes into account variables like tidal conditions, swell, and the underwater topography of the area.
These models are unable to accurately predict the height of each individual wave. They only provide a figure that reflects the general height of waves when they reach the coast. As mentioned before, statistical data are used that combine all the data obtained using averages to create what is known as a Gaussian bell curve.
I hope that with this information you can learn more about the waves of Nazaré.