Brazil is bracing for new storms just days after a devastating cyclone killed at least 41 people in the country's south, officials said.
Twenty-five people remain missing after an extratropical cyclone this week hit the state of Rio Grande do Sul, which is also the target of the new weather system.
Late Thursday, "a cold front will advance along the border with Uruguay and will reinforce instabilities in the southern regions of the state, expanding to northern areas between Thursday night and early Friday," according to a warning from the state government, citing a meteorologist.
Flooding from the earlier storm submerged whole neighborhoods in Rio Grande do Sol, forcing many people to climb onto roofs while awaiting rescue.
More than 10,500 people were forced to leave their homes in 83 municipalities hit by the cyclone.
Almost a thousand rescuers and a dozen helicopters were involved in rescue efforts that continued Thursday, complicated by the destruction of two bridges and 16 roads fully or partially blocked, officials said.
In the hard-hit town of Roca Sales, residents with picks and shovels were trying to recover whatever possessions they could from destroyed homes.
"Everything fell apart. I never saw anything like it here. It was crazy," resident Nelson Noll said, pointing to a now-empty space where three houses previously stood.
"This was no flood, it was a tsunami, a cyclone, which passed through here and took everything. There is nothing left," said the 75-year-old.
Brazil is not used to cyclones, but it is becoming "more and more frequent" for them to make landfall in the country, according to Francis Lacerda, a researcher at the Pernambuco State Agronomy Institute's Climate Change Laboratory.
Unchecked urbanisation and irregular housing built on hillsides are also making weather disasters deadlier in Brazil, experts say.
In June, another cyclone left 13 dead in Rio Grande do Sul and forced thousands of people from their homes.
And in February, 65 people died in landslides caused by record flooding in the southeastern resort town of Sao Sebastiao, on the coast of Sao Paulo state.
An estimated 9.5 million of Brazil's 203 million people live in areas at high risk of flooding or landslides.