As Beijing faces the coldest weather in three decades and heavy snow over the weekend, the city meteorological bureau reminded residents Thursday to wear warm clothes and be careful on the icy roads and sidewalks.

"Cotton-padded clothes, gloves, hat and mask are recommended to those who have outdoor activities," the bureau's hotline operator said Thursday. "The low temperature and snow will lead to frozen and slippery ground, so be careful when walking outdoors."

The bureau raised its Cold Wave Warning Signal to the blue level, its least serious level, indicating that "Less outdoor activities are advised."

It raised its Icy Ground Warning Signal to the yellow level, its second-least serious level, indicating "Try not to go outside as frequently as usual."

If any residents have a heating problem in their homes, they can call 96069, the city heating hotline.

Wang Qingwen, media officer of the Municipal Commission of City Administration and Environment, which controls the city's vast steam heating system, said that they would limit the temperature in shopping malls and office buildings to 22 C, and in government agencies to 20 C. "The purpose is to ensure more apartments are heated above 18 C," he said.

Zhang Chuandong, media officer of Beijing Heating Group, the largest state-owned organization providing heating services in Beijing, said that  all their boilers are running at full load in order to provide adequate heat indoors amid the low temperatures this winter.

"Apart from the heating, these factories also produce electricity for the city, but now they need to put supplying heat at a priority," he said. "Also, 140 people are standing by in case of a break-down of any heating system."

Because of the extra resources being directed toward the boilers, the amount of electricity being produced in gas and electricity power factories will be reduced.

"Some factories that consume gas and electricity would be temporarily closed to cover the gap," he said.

Skating in places like Beihai Park is already opened. But a representative of Nanshan Skiing Center said if the natural snow is too heavy, they would have difficulty in producing artificial snow.

"The natural snow is more humid and hard to be packed down," she said. "Loose and humid snow might not be suitable for skiing."