Monster waves in Europe's largest underwater canyon

Every year, the town of Nazaré experiences a huge wave season when the water can rise up to 30m high.

Nazaré is a famous hotspot for monster waves on the Portuguese coast. Every year, from October to March, big-wave surfers flock to the small fishing town when the swell reaches its annual peak. During that time, the water often rises as high as a five-story building, and sometimes twice that high, according to Live Science .

The town of Nazaré has become a hotspot for big waves. (Photo: RM Nunes).

Because of its giant waves, Nazaré is a destination for record-breaking surfers. In April 2024, German surfer Sebastian Steudtner set a new world record for the highest wave ever ridden by a human, riding a wave of 28.57m. The record has yet to be officially confirmed, but if confirmed, Steudtner would surpass his own current world record of 26.21m, set in 2020. The previous two world records of 24.4m and 23.8m were also set at Nazaré in 2017 and 2011.

In October 2010, 18-year-old Portuguese surfer António Laureano rode a wave in Nazaré that researchers later estimated to be 30.9m high. However, the International Surfing Federation has never recognized that result due to the method scientists used to calculate the wave's height.

The waves at Nazaré reach such impressive sizes because they form inside the Nazaré Gorge , Europe's largest underwater canyon , which is 210km long and 4.8km deep southwest of Nazaré in the Atlantic Ocean. The water in the gorge moves faster than the water in the shallower reaches, creating waves at great depths that curve toward Nazaré, according to NASA's Earth Observatory. As they approach the shore, the larger waves collide with waves coming from the northwest. The collision results in the creation of the giant waves.

Nazaré is known for its large waves, but it is not the site of the largest wave ever recorded. That title belongs to Lituya Bay in Alaska , which produced a 1,700-foot wave after an earthquake triggered a landslide that sent debris crashing into the bay in July 1958. The wave killed five people and flattened trees on the slopes surrounding the bay.

While Nazaré Gorge helps explain why this giant wave appeared on the Portuguese coast, giant waves can also occur suddenly at sea. Rogue waves are waves that are at least twice as tall as the surrounding ocean. They differ from tsunamis in that they are not the result of water displaced by earthquakes, landslides, or volcanic eruptions. Instead, the team suggests that rogue waves are generated by smaller waves merging into larger waves, either due to strong winds at the ocean surface or changes in ocean currents caused by storms.