Travel along a key river artery is becoming increasingly hazardous as huge chunks of ice threaten to bring shipping to a standstill.

Tens of thousands of people are on alert for possible flooding that may be caused by piled-up ice blocks in river courses.

Plunging temperatures have led to the build-up of ice along 111.39 kilometers in 33 sections of the Yellow River in East China's Shandong Province.

Statistics from the Shandong Yellow River Anti-Flood Office show ice blocks to be floating along the whole section of the river.

They are present at the river estuary in Heze in the eastern part of the province with the average ice density reaching 50 per cent.

At Dongying - the lowest reach of the river - the ice density reached 70 per cent on Thursday. Most ice blocks were between 1 to 10 square meters, with the biggest one recorded as 100 square meters.

Most ice blocks are 2 to 8 centimeters thick, with the thickest estimated to be 10 centimeters.

"The continuous cold weather will thicken the ice layer and close more sections, but everything is safe as far as we know," said Wang.

The official said an ice flood is unlikely, reducing the chances of a repeat of 1951 and 1955 when the river was effectively sealed.

The province has mobilized more than 450,000 people to tackle possible ice flooding.

They have checked and repaired all defences and facilities, as well as receiving training to combat ice floods.

Explosives have also been prepared in case ice-breaking becomes necessary.

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

The river passes through six cities in Shandong - Liaocheng, Dezhou, Jinan, Binzhou, Zibo and Dongying. These are the major cities that must fight against potential ice floods every year.

The river has not iced up in the past two years. Colder weather this year and slower river flow have led to more ice flow and icing up, said Wang Yixue, an official with the Shandong Yellow River Anti-Flood Office.

Weather forecasts were for a further decline in temperatures to -14 C last night in Jinan, capital city of Shandong.

Shandong has this year experienced the most serious drought in the past 100 years.

With little rainfall and more water being drawn from reaches of the Yellow River, the decreased flow of water has increased the formation of ice blocks and closed the river.

By 8 am Thursday, water flow at the lower Huayuankou Station in Zhengzhou, Henan Province, was merely 198 cubic meters per second, compared to the more than 400 for the same period last year.

(China Daily December 27, 2002)