Millions of Chinese shivered through power cuts and water shortages on Wednesday and millions more were stranded by snow that has blanketed parts of central and southern China.
The winter havoc was expected to last at least three more days, Xinhua news agency said, quoting forecasters.
About 50 people have died, including 25 on Tuesday in a bus crash on a snowy mountain road, and Premier Wen Jiabao has apologized to stranded passengers ahead of the biggest holiday of the year, the Spring Festival, which starts on Feb. 7.
Unusually icy temperatures, snow and sleet blanketing much of central, eastern and southern China have crippled thousands of trucks and trains loaded with coal, food and passengers in the most severe winter weather for some parts in half a century.
"Dealing with this snow disaster is even more complicated than tackling the floods of 1998 or other natural disasters we have faced," senior relief official Wang Zhenyao told state television.
The Yangtze River, China's longest, burst its banks in 1998, killing more than 3,000 people, but relief was at least able to be flown in.
"We can mobilize millions of troops to fight floods, but at the moment we can't even fly anyone in to offer relief."
Blocked roads and railways have also choked coal shipments, magnifying energy shortages that have caused power brownouts in 17 of China's 31 provinces and province-status cities.
In the booming southern province of Guangdong, many power plants had just two days of coal left, the official Guangzhou Daily reported on Wednesday, and authorities were shipping in emergency supplies on a fleet of 125 cargo ships.
More than 5 million people in the central and southern provinces of Hubei, Guizhou and Jiangxi have had water supplies reduced or cut off, and parts of Guizhou have spent two weeks without power, Xinhua news agency said.
Also in Guizhou, a bus plunged more than 40 metres (130 ft) from a mountain road on Tuesday, killing 25, adding to another 24 killed across 14 provinces in recent weeks.
"It was horrible. I was frightened to see many people, dead or alive, lying on the ground after I opened my door and heard cries for help," Xinhua quoted Gao Zhibin, one of the first people on the scene, as saying.
Wen used a megaphone to tell train passengers stuck at Changsha station in southern China he was sorry.
"I am deeply apologetic that you are stranded in the railway station and not able to go home earlier," he said. "We are now doing our best to fix things up and you will all be home for the Spring Festival."
Migrant workers in Guangdong were urged to abandon plans to go home for the holiday, when Chinese celebrate the Lunar New Year. It is a traditional time for family reunions, the equivalent to Thanksgiving in the United States.
"Guangdong is your home and let's combat the worst freezing disaster in decades together," Xinhua cited a government open letter to migrant workers as saying.
Although all airports previously closed by the snow have reopened, millions of people remained trapped at stations and on highways.
"Railway authorities in Guangzhou, Shanghai, Hangzhou, Beijing, Jinan and Kunming have been forced to stop selling tickets and refund those already sold," Xinhua said.
"However, most passengers have been reluctant to return their tickets, hoping railway operations will soon resume."
In China's booming business capital of Shanghai, state radio said many delayed trains had begun to arrive, adding that services should start returning to normal by Wednesday.
Analysts said the brutal weather was a short-term blow to the economy and would stoke inflation that already has the government worried. It hit an 11-year high of 4.8 percent last year.