The National Meteorological Center has declared the recent heavy rainfall in the Beijing-Tianjin-Hebei region from Saturday to Tuesday "a historically extreme event".

The intensity of the rainfall surpassed previous significant rainstorms in the region, including those in 1996, 2012 and 2016.

During the four days, rainfall pummeled Beijing for 83 hours, the center said.

Over three days, 26 national weather monitoring stations reported accumulated rainfall exceeding historical records.

The extreme heavy rainfall in the Beijing-Tianjin-Hebei region can be attributed to typhoons and the mountainous landscape in the region, said Zhang Hengde, deputy director of the center.

An abundant supply of water vapor in the atmosphere was brought by the remnants of Typhoon Doksuri and combined with the southeastern airflow of a subtropical high and moisture transported from distant Typhoon Khanun, said Zhang.

"The vapor had been converging toward the North China Plain. Plus, the presence of mountain ranges such as the Taihang and Yanshan mountains caused an uplifting motion, forcing the water vapor to condense and intensifying the rain," he said.