A hydroelectric dam has collapsed in southern Brazil after days of heavy rains that triggered massive flooding, killing more than 30 people.
Officials say another 60 people are missing in Rio Grande do Sul state.
About 15,000 residents have fled their homes since Saturday. At least 500,000 people are without power and clean water across the state.
The burst dam triggered a two-metre (6.6ft) wave, causing panic and further damage in the already flooded areas.
The dam is located between the municipality of Cotiporã and the city of Bento Gonçalves.
The extreme weather has been caused by a rare combination of hotter than average temperatures, high humidity and strong winds.
Brazilian President Luiz Inácio Lula da Silva has visited the region, promising help from the central government.
Earlier, state Governor Eduardo Leite pleaded for urgent assistance, saying that "we need to rescue hundreds of people in dozens of municipalities".
Helicopters have been deployed to search for stranded people.
In some areas, the flooding is so severe that helicopters have been unable to land and have had to winch residents to safety.
In the Candelária municipality, residents took to the roofs of their homes as their houses filled with water.
Meteorologists have predicted further rains to fall in the region as a cold front moves across it.
Last year, more than 30 people were killed in a cyclone in Rio Grande do Sul.
Brazil's National Institute of Meteorology attributed the increased intensity and frequency of rainfall to the climate phenomenon El Niño.
