At least 36 people have been killed in flooding and landslides in Brazil’s São Paulo state, officials say.
Dozens of people are missing and while the number of dead is expected to rise, rescue workers say they hope to pull some of those trapped in flooded homes out of the mud alive.
Video showed neighbourhoods under water, inundated motorways and debris left after houses were swept away.
Carnival celebrations have been cancelled in a number of cities.
In the coastal town of São Sebastião, 627mm of rain fell in 24 hours, twice the expected amount for the month.
The town’s mayor, Felipe August, said the situation there was chaotic: “We have not yet gauged the scale of the damage. We are trying to rescue the victims.”
Some 50 houses had collapsed and were washed away, Mr Augusto added, saying that the situation remained “extremely critical”.
The state government reported at least 35 deaths in São Sebastião and in Ubatuba, some 80km (50 miles) north-east, a seven-year-old girl was killed when a boulder weighing two tonnes hit her home.
Hundreds have been displaced and evacuated.
“Unfortunately, we are going to have many more deaths,” a civil defence official told newspaper Folha de São Paulo.
State Governor Tarcísio de Freitas said he had released the equivalent of $1.5m (£1.2m) in funding to aid in disaster relief.
Carnival events were cancelled across parts of the coastline, which is a popular destination for wealthy tourists looking to avoid huge streetside festivities in the big cities.
The festival usually lasts for five days in the run-up to the Christian festival of Lent and the colourful celebrations are synonymous with Brazil.
Latin America’s largest port in Santos was also shut as wind speeds exceeded 55km/h (34mph) and waves rose to over a metre, local media reported.
President Luiz Inácio Lula da Silva, who was spending the carnival weekend in the north-eastern state of Bahia, will visit the affected areas later on Monday.
In a post on Twitter, he sent his condolences to those who had lost loved ones and promised to bring authorities together to provide healthcare and rescue teams.
“We are going to bring together all levels of government and, with the solidarity of society, treat the wounded, look for the missing, restore highways, power connections and telecommunications in the region,” President Lula wrote.
More heavy rain is expected in the area, threatening to make conditions even worse for emergency teams.
Extreme weather events such as the floods are expected to become more common as the impacts of climate change take hold.
Last year, torrential rain in the south-eastern city of Petropolis killed more than 230 people.