China's Yellow River could freeze, say authorities
Chinese authorities say the Yellow River, the country's second biggest, could completely freeze over amid plunging temperatures.
More than 500 people have been called in to monitor the movements of huge chunks of ice down the river, amid fears there could be flooding if the floats pile up and block the river's progress.
Authorities say the river will be entirely frozen within five days of temperatures reaching -15C.
The BBC's Peter Dobbie reports