The phenomenon, which mainly affected the northern provinces of Hebei and Liaoning, caused flooding and forced the mobilization of an emergency response, surprised both authorities and the local population, said the Hong Kong newspaper South China Morning Post.
The director of the Tidal Wave Forecasting Office of the National Center for Marine Environmental Prediction, Fu Cifu, was quoted as saying by the newspaper that such a sudden rise in water level, in the absence of wind and obvious waves, “has never been recorded ”, neither at national nor international level.
Sea levels in several areas in the region remained about one meter above normal for more than 20 hours, surpassing historical records at several tide gauge stations in Liaoning province.
Authorities said that although the waters began to recede after several hours, the effects of the wave were felt in more southern provinces such as Jiangsu (east) and Fujian (southeast).
Even in the South China Sea, in regions such as Hong Kong and Macau, tides were 30 centimeters higher than normal, the newspaper added.
Videos posted on social media show submerged roads in cities in the northeast of the country, such as Dalian and Jinzhou.
Rising sea levels triggered an emergency response from China’s Ministry of Natural Resources, which mobilized five teams of experts to inspect affected areas.
An unnamed expert from the Ministry of Natural Resources, cited by the South China Morning Post, indicated that tidal fluctuations caused by a storm, along with tides, began to have an impact several days before the event.
A flow of warm, moist air moving north along the Yellow River met a cold front advancing from the south, resulting in the formation of a typhoon-type cyclone, which generated a thunderstorm in the region, the expert said, warning that “in In the context of global climate anomalies, extreme weather events can arrive silently without warning.”
The oscillation reportedly began on October 19 in Bohai Bay, spread south, and then rose again to Liaoning, where it coincided with high tide, causing the phenomenon.
On local social media, amateur meteorologists explained that the rise in sea levels was due to a combination of astronomical, meteorological, oceanographic and topographic factors.
Among these factors, they noted that October 20th coincided with the strongest astronomical tide of the year, as well as a newly recorded supermoon, which increased tides by up to 20 centimeters.
Authorities have not reported any victims so far.
*With Lusa