Increase in temperatures contributed to recent heavy rainfall, forecaster says

The extraordinary flood raging along the Beijiang River in southern China, which arrived two months before the usual time for floods of similar intensity, provides new evidence that the climate crisis is looming larger, an expert said.

On Monday, the Shijiaowen hydrological station on the Beijiang in Qingyuan, Guangdong province, reported a flow of 18,100 cubic meters per second, well above its annual average of 2,400 cubic m/s for the same day, according to the Ministry of Water Resources.

A major tributary of the Pearl River, the Beijiang originates in Jiangxi province, with most of its length in Guangdong.

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The unusual flooding is happening because many areas in southern China are experiencing more precipitation amid higher than normal temperatures.

From Thursday to Monday, 16 counties in Guangdong and the neighboring Guangxi Zhuang autonomous region reported precipitation that exceeded the record amounts seen on the same days in previous years, the ministry said.

It said 36 rivers swelled above their flood warning marks on Sunday and Monday.

The National Meteorological Center said most areas south of the Yangtze River, including Guangdong and Guangxi, received 40 to 80 millimeters of rainfall from April 13 to Monday, which is 40 to 80 percent more than their historical averages for the same period.

Precipitation in some places in Guangdong even reached 250 mm to 450 mm, it said.

It also noted that average temperatures in most regions across the country in the past 10 days were 1 to 3 C higher than usual.

Ma Xuekuan, chief forecaster at the center, said the increase in temperatures was one of the reasons for the recent heavy rainfall south of the Yangtze.

The higher temperatures have led to abundant moisture and high unstable energy in the atmosphere, Ma said, which could cause sudden and very destructive weather that often includes thunderstorms, hail, strong winds and heavy rain.

Ma said the subtropical high pressure that has been stronger than usual this month is another factor to blame, as it has created favorable conditions for the transport of water vapor from the South China Sea and the Bay of Bengal to southern China.

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Yin Zhijie, chief hydrological forecaster with the Ministry of Water Resources, pointed to climate change as the hidden force behind the extraordinary flood.

"Based on the flood control situation in recent years, extreme heavy rainfall occurs every year as the trend of rising temperature intensifies with a warming climate," he said. "Downpours and floods are direct results of such extreme weather events."

The National Meteorological Center has warned of more rainfall and severe weather events until May 2.

About 50 to 120 mm of rainfall is forecast to fall in the region from Tuesday to May 2. In some areas, precipitation may exceed 400 mm, the center said. That means they may receive 50 to 80 percent more precipitation than their historical averages for the same period.

Contact the writers at houliqiang@chinadaily.com.cn