Flood-control authorities along the Yellow River remain on high alert for possible ice floods as satellite images show the river is thawing along the river course, sources at the Yellow River Water Conservation Committee said on Friday.

Ice has covered the second largest river in China from its upper reaches since early December. More than 1,124 kilometres, or one-fifth of its total length, has been frozen since mid-January. The 720-kilometre section in the Inner Mongolia Autonomous Region has completely frozen, and ice has been building up.

Meanwhile, ice in the middle and lower reaches of the river began to melt quickly as the weather turned warmer. In Shandong, the last province the river passes through, only 39 kilometres of river was still frozen compared with 233 kilometres in mid-January, Liu Hongcai, an official from the Shandong Provincial Yellow River Anti-flood Office, told China Daily yesterday.

"Floating ice blocks in the river, as a result of the thawing, threatened people and property. It was more dangerous when ice in the upper reaches of the river began to dissolve while its lower reaches are still frozen. Water would rush down and there was a possibility of forming an ice dam, cutting off water flow and eventually leading to flood," Liu said.

This winter has been particularly cold, and the prolonged low-temperatures have led to the river's longest period of ice-covering since 1986. Experts say that a longer ice-covering period and more ice blocks mean heavier anti-flood duties.

Nevertheless, prevention work has been organized along the waterway.

The Yellow River Water Conservation Committee said it has worked out contingency plans to deal with possible flooding and has instituted round-the-clock inspections of the dams along the river.

Shandong Province has mobilized more than 400,000 people to tackle possible ice flooding. They have checked and repaired all the dykes and facilities, as well as receiving training in combating ice floods. Explosives have also been prepared in case ice-breaking becomes necessary, according to officials.

Though there has been no serious ice flood along the river, minor ones did occur at Yongning, Northwest China's Ningxia Hui Autonomous Region, on February 11 and 12. To date water has flooded more than 867 hectares of riverside land.

The Yellow River starts in Qinghai Province in Northwest China. It then flows through Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi and Henan, before passing through Shandong and entering the Bohai Sea.

(China Daily February 28, 2005)