Rare floods ravaged areas along the middle and lower reaches of China's Yellow River in September and October as heavy rain not seen in decades hit the region this autumn, National Climate Center said on Thursday.

In the next few weeks, most of the Yellow River Basin is expected to see 10 to 20 percent more precipitation than normal, the National Climate Center said.

On Oct 5, the lower reaches of the Yellow River in Jinan section, Shandong province, experienced heaviest autumn flood over the past 36 years, local authority said.

Four days later, the Fenhe River in Hejin city, Shanxi province, a major tributary of the Yellow River, saw biggest flood since 1964, the local water bureau said.

From Sept 27 through Oct 5, the Yellow River Conservancy Commission under the Ministry of Water Resources released three alerts for flood along the river as the amount of water flowing per second exceeded the warning line.

The recent severe floods in Shanxi have affected 1.75 million people and damaged more than 17,000 houses, the provincial emergency management bureau said on Oct 10.

The National Climate Center said that autumn rain in West China caused the Yellow River Basin's flood in September and October.

In September, precipitation in the basin hit record high in the same period since 1961, nearly tripling that of normal years, the center said.

In West China, autumn rain, a regular weather phenomenon in the country, usually lasts from September to November and leads to autumn rainy seasons in Sichuan, Yunnan and Guizhou provinces and Chongqing municipality.

The most typical case was the autumn rain in 2003 that caused more than 10 rounds of floods in the Yellow River mainstream and tributaries from August through October. Shandong and Henan were severely affected, the center said.

"This year's autumn rainfall in the basin was similar to that in 2003, but heavier," the center said.

"The autumn flood this year lasted longer and were more severe than normal years. It made the fight against the flood harder as both the mainstream and tributary swelled at the same time," Jiang Enhui, deputy head of Yellow River Institute of Hydraulic Research, told Science and Technology Daily.

The National Meteorological Center warned of geological disasters as soil has been full of water which reduced its capability to withstand floods, especially in Gansu, Shanxi and Shaanxi provinces where the Yellow River runs through.

An outline released by the central government on Oct 8, said that floods caused by climate change and extreme weather still pose threats to nearly 1 million people in the basin's downstream areas despite improvement in the river's environment.

Along the Yellow River, agricultural production areas account for about a third of the country's grain and meat output, the outline said.

"China will improve its flood prevention system by reservoirs stopping excessive floodwater from upstream, managing river way and creating flood detention areas besides banks," the outline said.