According to satellite images from the National Satellite Meteorological Center, the area occupied by sea ice in Liaodong Bay, off the coast of Liaoning province, increased to 4,715 square kilometers on Monday.

Zhang Fanghua, chief forecaster at the National Meteorological Center, said it is normal to see cold air movements in the winter and the cold spell has nothing to do with doomsday prophecies related to the Mayan calendar.

She said the current movements, although frequent, will not cause the kind of severe damage that arose from a series of winter storms in 2008, which claimed more than 100 lives.

Authorities, though, are preparing for blizzards.

The Beijing city government held a conference with energy companies on Wednesday to get ready for a likely peak in energy consumption. Nearly 7 billion cubic meters of natural gas is expected to be burned for central heating this winter, about 800 million cu m more than in the previous heating season.

A 1-degree drop in temperature normally results in an additional 2 million cubic meters of gas being used in central-heating systems.

To conserve natural gas, authorities have asked hotels, shopping malls and office buildings to keep temperatures below 22 C during the hours when they are open.

Authorities in the Ningxia Hui autonomous region and Gansu province issued warnings on Wednesday afternoon about the coming snowstorms and temperature drop.