5 January 2012 Last updated at 17:27 GMT
Brazilian authorities are trying to evacuate several thousand people after a dam burst in northern Rio de Janeiro state.
Water broke through the dam protecting the town of Campos de Goytacazes, opening up a big crater in a highway.
Rio and other parts of south-eastern Brazil have been battered by floods and landslides, with several people killed.
Some 66 towns and cities in Minas Gerais state have declared a state of emergency.
On Thursday, a dam protecting Campos de Goytacazes ruptured, sending floodwaters from the River Muriae towards the small community of Tres Vendas some 30km (19 miles) away.
Officials said it was a race against time to get the people out before the area was flooded.
“Practically all the families are leaving,” civil defence official Henrique Oliveira told the G1 website.
“The river might rise three and half metres, four metres. Only the roofs will be visible.”
Flooding is common in south-eastern Brazil during the rainy season. Nationwide, more than two million people have been affected by this year’s rains, Brazil’s civil defence force says.
Floodwaters are also threatening hillside communities in Rio de Janeiro state that were devastated a year ago.
Many roads have been blocked, making it difficult to get help and supplies to affected areas.
Last year floods killed more than 800 people, in what officials said was the worst natural disaster ever to befall Brazil.
Most of the deaths were in towns in the mountains north of Rio de Janeiro such as Nova Friburgo, which are again suffering from intense rains.
Since then, the Brazil government has set up an early warning system to monitor weather rainfall and ensure people evacuate before floods strike.