Widespread downpours prompt flood warnings

The national weather authorities have issued a Level II emergency response, the second highest in a four-tier system, for torrential rainfall, as a vast stretch of areas across the country are forecast to experience brief but heavy downpours through Thursday.

On Monday, Sichuan, Henan and Shaanxi provinces had heavy rainfall, with Nanyang and Zhoukou in Henan hit especially hard. The meteorological station in Sheqi county of Nanyang recorded 418.6 millimeters of precipitation between 8 pm on Monday and 6 am on Tuesday, setting a local record, according to the National Meteorological Center.

From Tuesday to Wednesday, heavy rainfall was expected to affect more regions, including the Sichuan Basin, which covers Sichuan province and Chongqing municipality, as well as Henan, Shandong, Jiangsu and Anhui provinces, the center said.

Some parts of these regions may experience severe convective weather, which refers to sudden and very destructive weather conditions that often include thunderstorms, hail, strong winds and heavy rain, according to the center.

It said that in the 24 hours starting at 8 am on Tuesday, the hourly precipitation in these regions could reach 30 to 50 mm. In light of the expected heavy precipitation, the center decided to issue the emergency response at 9 am on Tuesday.

The heavy rainfall in these regions could last until Saturday, with the accumulated precipitation in certain areas hitting 500 mm, said Chen Fanghua, chief forecaster at the China Meteorological Administration, during an online news conference on Tuesday.

She said the rainstorms, which started about 10 days ago and have been marked by high intensity, long duration and concentrated distribution, resulted from the interaction between the warm and humid airflow from the southwest and the weak cold air from the north.

The intense rainfall in Henan has significantly affected the province's highway system. On Tuesday morning, Henan highway authorities shut down or restricted access to 21 highways across the province.

In an effort to cope with potential major flooding, the Three Gorges Dam on the Yangtze River in Hubei province opened another six of its flood discharge gates on Sunday in order to increase its capacity to store floodwater from the upper reaches of the Yangtze, where the Sichuan Basin is located.

The dam, the world's largest hydropower project, opened its flood discharge gates for the first time this year on July 10. At that time, the outflow from the reservoir stood at just 27,000 cubic meters per second. The speed has now increased to 43,000 cubic m/s.

The move at the Three Gorges Dam on Sunday came as China enters the annual period that is historically prone to flooding, from mid-July to mid-August. Forecasts indicate that the upper reaches of the Yangtze may be hit by major flooding during this period.