The Qiantang River in China is famous for its unique natural phenomena. (Photo: Oddity Central)
CHINA – The Qiantang River in China is famous for its unique natural phenomenon, namely wavy patterned tidal waves. This phenomenon was first observed in 2021 and is known as the fish scale wave.
Quoted from Oddity Central, Thursday (19/10/2023), the mouth of the Qiantang River in Zhejiang Province has long been famous for having large tidal waves. At times, these waves can reach heights of nine meters, meaning the area regularly experiences a series of large waves moving upstream against normal currents.
However, in 2021, during a scientific expedition, researchers discovered another interesting natural phenomenon in this estuary. When certain conditions are met, the tide comes in spiral waves that look like fish scales on the surface of the water. This phenomenon is known as fish scale waves.
Because this unusual tide pattern was only observed a few years ago, the exact reason for this phenomenon is still a matter of debate. Different sources cite different reasons for the formation of fish scale waves. For example, FyFluidDynamics believes this phenomenon is the result of a series of factors.
“This area is also known to have rotating currents, meaning the tide doesn’t just move inland and then smoothly reverse direction,” writes Nicole Sharp.
In contrast, he said, rotating currents can change their flow direction during the tidal cycle without changing their speed. Combined, this makes the Qiantang River region perfect for generating clusters of waves that collide at oblique angles, similar to a cross sea. Two tide-induced waves collide at an angle, creating interesting conditions and a very cool pattern.
According to INF News, astronomy, topography and wind direction are the main factors that produce waves of fish scales. Apparently, the moon and sun also play a big role in this rare natural phenomenon. Likewise, the shape of the estuary is very narrow at the mouth of the river, but very wide where it meets the sea.
Whatever the exact conditions required for fish scale waves to form, one thing is certain, these events rarely occur simultaneously, which is why this phenomenon is so rare.