Main sections at the lower reaches of the Yellow River, China's second longest watercourse, have frozen Friday Morning due to an abrupt temperature drop in eastern Shandong Province, where the river empties into the Bohai Sea.

The provincial Yellow River water conservancy authorities say dropping temperatures on Thursday have caused a large-scale area of the river's lower reaches to freeze at night.

The authorities warn that if the temperature keep going down in the coming days, whole lower reaches will get frozen. So far, 50 to 60 percent of the river's estuary have frozen and in the other sections, 20 to 50 percent of the river size have frozen.

When the Yellow River freezes -- which usually lasts until early spring, water accumulates upstream, leading to higher water levels in parts of the river and then to floods. The floods can pose a threat to the safety of embankments along some narrow and winding sections of the river.

The Yellow River, known as China's mother river, starts in Qinghai Province in the northwest and flows through Gansu, Ningxia, Inner Mongolia, Shaanxi, Shanxi and Henan, before passing through Shandong and entering the Bohai Sea.
 
(Xinhua News Agency January 7, 2006)