Rains threaten quake lake disaster

CHENGDU, China (Reuters) - The onset of the rainy seasonthreatens to swell dangerous "quake lakes" and compound thedifficulties of reconstruction after China's worst earthquakein decades.

The 7.9 magnitude tremor of May 12 and thousands ofaftershocks changed the landscape of northern Sichuan provinceforever, blocking rivers, weakening mountain walls and creatingunstable lakes where there was once dry land.

The death toll had passed 55,000, with almost 25,000missing and more than 281,000 injured, Sichuan vice governor LiChengyun said on Friday as fears grew that disease, rain andaftershocks could bring yet more disaster to the southwesternprovince.

He said this was a "peak period for outbreaks of diseases",describing the situation as very grim, but was optimistic aboutshort-term relief.

"We will strive to provide safe, economical and convenienttemporary housing for 98 percent of the residents within thenext month," Li told a Beijing news conference, adding that itwould take three years to rebuild "new villages, towns andcities".

A landslide triggered by an aftershock in Wenchuan county,at the epicentre, on Thursday crushed a house, killing twopeople, state media said on Friday.

In Chengdu, some volunteer relief convoys reported beingheld up by hungry residents, one at gunpoint. There werereports of two people being beheaded by helicopter blades, oneat the Wolong panda reserve, sources in Sichuan and localreporters said.

Premier Wen Jiabao, making his second visit to the disasterzone, visited hospitals and tents sheltering quake refugees onFriday in Beichuan county, one of the worst-hit areas.

In a temporary shelter for the Beichuan Middle School,which lost up to 1,000 students and teachers in the quake, Wentried to cheer up children, writing a line on the blackboardreading "Deep distress resurrects a nation".

Wen, a trained geologist, had earlier ordered rescueworkers to eliminate the danger of the lakes "throughengineering means" while swiftly evacuating people in theirpath.

In Hongguang, in northeastern Sichuan, the earthquakecaused both sides of a valley to slide, burying three villagesand 900 people. The Qingzhu River is trapped behind.

"The mountains merged," said Gao Xiao, who barely escaped alandslide that roared past her house.

The Qingzhu landslides have formed five lakes, the biggestof which is almost 30 metres (100 feet) deep. A flood controlteam monitors the natural dams constantly, for fear they willburst and unleash a wall of water on the valley below.

The more than 30 barrier lakes in the quake were safe forthe moment and residents under threat had been evacuating, ZhuBing, a Sichuan water resources official, told the newsconference.

"There is a possibility of (the dam) collapsing entirely inthe case of a strong aftershock or rainstorm," Zhu said of theTangjiashan barrier lake in Beichuan which Wen toured onThursday.

Heavy rain is forecast, making life even more difficult forrescuers, relief workers and the 5.48 million either living intents or under makeshift cover as their mourn their dead.

Sichuan has been on high alert for epidemics, said vicegovernor Li. "The most-needed items remain tents andpre-fabricated housing units," he said. "We also need hygieneequipment such as street-cleaning and water-spraying vehicles."

(Additional reporting by Guo Shipeng in Beijing; Writing byNick Macfie; Editing by Roger Crabb)