The Pororoca (, ) is a

tidal bore Tidal is the adjectival form of tide. Tidal may also refer to: * ''Tidal'' (album), a 1996 album by Fiona Apple * Tidal (king), a king involved in the Battle of the Vale of Siddim * TidalCycles, a live coding environment for music * Tidal (servic ...

, with waves up to high that travel as much as inland upstream on the

Amazon River The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile. The headwaters of t ...

and adjacent rivers. Its name might come from the indigenous

Tupi language Old Tupi, Ancient Tupi or Classical Tupi (also spelled as Tupí) is an extinct Tupian language which was spoken by the aboriginal Tupi people of Brazil, mostly those who inhabited coastal regions in South and Southeast Brazil. It belongs to the ...

, where it could translate into "great roar". It could be also a Portuguese version of the term ''poroc-poroc'', which in an indigenous' language was a way of expressing the act of destroying everything. It could be also a ''

portmanteau A portmanteau word, or portmanteau (, ) is a blend of words It occurs at the mouth of the river where its waters meet the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

Explanation

During

new New is an adjective referring to something recently made, discovered, or created. New or NEW may refer to: Music * New, singer of K-pop group The Boyz Albums and EPs * ''New'' (album), by Paul McCartney, 2013 * ''New'' (EP), by Regurgitator, ...

and

full moon The full moon is the lunar phase when the Moon appears fully illuminated from Earth's perspective. This occurs when Earth is located between the Sun and the Moon (when the ecliptic coordinate system, ecliptic longitudes of the Sun and Moon opp ...

s, when the ocean tide is highest, water flows in from the Atlantic, rather than the other way around. The Amazon's flow reverses, the distance of which depends largely on the rainwater-generated outflow of the Amazon, and a water bulge speeds upstream often with great force, forming a

with an audible noise. The tidal phenomenon is best observed on biannual equinoxes in September and March during a

spring tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ca ...

. On an equinoctial spring tide, the Moon and Sun fall into direct alignment with the Earth, and their

gravitational pull In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stron ...

is combined, bringing the Pororoca and others around the world to their peak.

Surfing

The wave has become popular with

surfers Surfing is a surface water sport in which an individual, a surfer (or two in tandem surfing), uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suitabl ...

. Since 1999, an annual championship has been held in

São Domingos do Capim São Domingos do Capim is a Brazilian municipality in the state of Pará. The estimated population is 32,139 (2020). It has an area of 1677 km2. The city is well known for hosting a world surfing championship in the bore tides of the Guamá ...

(on the adjacent

Guamá River The Guamá River is located in northeast Pará state in north-central Brazil. Its mouth forms the southern border of the state capital, Belém. Its watershed drains an area of . The navigability is feasible in the last of the river, from the mun ...

). However, surfing the Pororoca is especially dangerous, as the water contains a significant amount of debris from the shores of the river (often entire trees), in addition to dangerous fauna. In 2003 the Brazilian Picuruta Salazar won the event with a record ride of 12.5 km (7.8 mi) lasting 37 minutes.

Notes

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External links

Corran Addison about the Pororoca Wave - Playak.com
Amazon River Tidal bores Natural history of South America River surfing Surfing locations in Brazil fr:Amazone (fleuve)#Vague déferlante