(AP) Some of the worst winter weather to hit southern China in decades took 25 more lives Tuesday when a bus plunged off an icy road, adding to the chaos the snow storms have caused during the nation's peak travel season.

Numerous cities suffered blackouts as heavy snowfalls caused power lines to snap and hampered the delivery of coal, used to generate most of China's electricity. Around 50 deaths so far have been blamed on the weather.

The storms also stranded travelers, among them hundreds of thousands of migrant workers heading home for the Chinese New Year. The holiday, which begins Feb. 7, is China's most festive. For many migrants, it is their only chance to visit their families, and by Tuesday many had given up trying to go.

Premier Wen Jiabao visited Changsha, capital of central Hunan province, which has suffered its heaviest snowfall levels since 1954, according to the official Xinhua News Agency.

Wen issued instructions to clear ice from roads and power cables. Much of the disruption to the grid has been blamed on the accumulation of ice and snow on power lines, weighing them down and causing them to snap.

Because of the snowfall, Wen was forced to fly to an airport in the neighboring province of Hubei and complete his journey by overnight train.

Power plants that produce 7 percent of China's electricity have shut down for lack of fuel, Xinhua said Tuesday, citing the State Electricity Regulatory Commission. Other plants accounting for a further 10 percent of the electricity supply have less than three days' reserves, it said.

Trains are delivering less than 25 percent of normal daily coal shipments due to bad weather obstructing transportation, Xinhua said, citing the Railways Ministry.

The Politburo of the ruling Communist Party warned that the bad weather would continue at an emergency meeting held Tuesday and chaired by Secretary-General Hu Jintao, who is also president.

"In the next few days, there will be more severe weather in some southern areas. The government departments and localities must be aware of the seriousness of the situation and be fully prepared to prevent and fight disasters," it said in a notice.

The extreme weather has been blamed for nearly 50 deaths over the past two weeks. In the latest accident, a bus plunged 40 yards off a road into a valley in mountainous Guizhou province, the State Administration of Work Safety said.

The 35-seat passenger bus was carrying 38 people when it went crashed, killing 25, the safety watchdog said. Two passengers were hospitalized in critical condition and the other 11 had slight injuries.

The road was covered with a thick layer of ice and snow, highly unusual for the southern province where the winters are normally mild, Xinhua said.

Meanwhile, the number of migrant workers stuck at the main train station in the southern city of Guangzhou dropped to 200,000 _ from a high of 500,000 _ as many simply gave up trying to make the annual trip home and cashed in their tickets, railway officials said.

The workers have been camped out in the station's plaza over the last several days as heavy snowfall in provinces to the north cut off parts of the busy railway line that starts in the city and ends in Beijing.

Traffic on the Beijing-Guangzhou line may not return to normal for three to five days, the official Xinhua News Agency said.

Red banners at the Guangzhou train station encouraged travelers to cash in their tickets and stay in the city.

The train station plaza looked like a massive canopy of umbrellas, as people waited for their trains in a bone-chilling drizzle. Tens of thousands of others were camping beneath a highway overpass in front of the station.

Many like Wang Jigen, a 50-year-old construction worker, were hanging around the station because they had no other place to go. Wang left his job and had just enough money to go home to the westrn province of Sichuan. His train was canceled and he couldn't afford to stay in a hotel.

"I spent last night outside at a bus depot," said Wang, dressed in a tattered sweater and a corduroy coat. "I have no idea where I'll sleep tonight or how I'll ever get home."

Construction worker Liu Chenmin, 43, said he visits his family in neighboring Hunan just three times a year, though the trip is just eight hours by train. His hopes of getting a train were fading fast, and he had already warned his family _ a wife and a teenage son and daughter _ that he might not be home for the holiday.

"I just called them and they are really disappointed but they understand because my hometown is buried in snow," he said. "But spending the holiday here is going to be sad and uncomfortable for me."

The severe weather has caused economic losses of $3 billion since it began Jan. 10, the Civil Affairs Ministry said.

Shanghai was blanketed in white after sleet changed to snow overnight, leaving city streets slick with slush. The city's expressways remained closed and traffic was slow. Trains and flights from the city to many destinations were delayed.

"Now you can buy train tickets only to nearby cities like Hangzhou and Suzhou. No long-distance train tickets are available. No idea when things will be back to normal," said a staffer who answered the phone at the Shanghai Train Station. He gave only his surname, Yuan.