Astonished onlookers gasp at the raw power of floodwaters

A three-story building proved to be no match for the strength of an overflowing reservoir in China's Henan Province. After days of intense rain, the water levels in the Yahekou Reservoir discharged into the city of Nanyang, triggering devastating results for one huge building.

In footage captured by a resident identified as Mr. Fang on Sept. 25, the building can be seen crumbling into the flooded river, splintering apart as it tumbles before washing away in the fierce current. People can be heard in the footage gasping as the building came down and was swiftly washed away. According to Newsflare, no one was injured. Nanyang is located in northeastern China, about a five-hour drive north of Wuhan.

According to the Financial Associated Press, the city received nearly 19 inches of rain in a 24-hour span. The intense flooding that was triggered by the nearly 2 feet of rain reportedly caused 80 local small and medium-sized reservoirs to spill over, including more than two dozen that were overtopped by at least 3 feet of water.

In the Yahekou Reservoir, waters rose 3.28 feet every hour, according to the report. That severe situation spelled quick doom for the three-story building, which went from intact to washed away in just a matter of seconds.

"Since the early morning of the 25th, Yahekou Reservoir began to discharge flood, and the water level of the reservoir is falling continuously," the news outlet reported on Sept. 26. The report described a rapidly rising inflow of water in the reservoir, which dwarfed the amount of water flowing out of the reservoir.

Hydrologist Victor Baker told AccuWeather earlier this year that a typical water flow in a stream is a few feet per second, but the strength of a flash flood could be 10 times that.

"If the water velocity is 10 times what you usually see, the energy is 100 times what you usually see," he told AccuWeather's Monica Danielle. "That is because energy goes up with the square of velocity."

According to AccuWeather Meteorologist Mary Gilbert, the intense water velocity that was strong enough to down the three-story building was fueled by a stalled storm front that inundated portions of China with repeated rounds of rain.

Seven-day precipitation estimates from NASA GPM indicate that over 457 mm (about 18 inches) of rain fell near Nanyang between Sept. 20 and 27, 2021.

Some of these storms exhibited what is known as a training effect, she said, which is when storms unleash rain on the same area, one after another.

"Repeated rounds of rain in a short amount of time can lead to dangerous, perhaps deadly flash flooding," Gilbert said. "Rivers or streams may burst their banks, simply because the amount of water pouring into them has nowhere else to go."

This is the latest dramatic footage to emerge from China in recent months during significant flooding events. Over the summer, torrential rains triggered severe flooding in multiple Chinese provinces. In one instance, runaway boats could be seen plunging over a raging waterfall. In another instance, more than 50 were killed during severe flooding, but many others were saved in harrowing rescue operations that were caught on camera and went viral.

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