Authorities in the Brazilian state of Sao Paulo report that heavy flooding and landslides have killed at least 36 people, forcing some cities to postpone their annual Carnival celebrations.
Video displayed submerged neighborhoods, flooded highways, and debris left behind after houses were swept away.
Rescue workers have had difficulty getting to survivors and clearing traffic.
Some areas received twice as much rain on Sunday—more than 600mm (23 point 6 inches)—than was predicted for the entire month.
The situation is chaotic, according to Felipe Augusto, mayor of the severely damaged town of So Sebastio. "Search and rescue teams are not managing to get to several places," he added.
"We still haven't determined the extent of the damage. We're working to save the people. ".
Mr. Augusto continued, stating that the situation remained "extremely critical," adding that the town had dozens of missing people and that about 50 homes had collapsed and been destroyed.
At least 35 deaths were reported by the state government in So Sebastio, and a young girl's death was reported by the mayor of Ubatuba, located about 80 kilometers (50 miles) to the northeast. Hundreds of people have been evacuated and displaced.
Sadly, there will be a lot more fatalities, a civil defense official told the newspaper Folha de So Paulo.
According to officials, 338 more people were evacuated from coastal regions north of So Paulo, leaving another 228 people without a place to live.
Six towns in the state—So Sebastio, Caraguatatuba, Ilhabela, Ubatuba, Guarujá, and Bertioga—were placed under a 180-day state of calamity.
Governor of the state Tarcsio de Freitas declared that he had made funding for disaster relief totaling $1.5m (£1.2m) available.
Carnival activities were postponed along the northern coastline, a popular destination for wealthy travelers trying to avoid the intense street celebrations in the major cities.
In the lead-up to the Christian festival of Lent, the festival typically lasts for five days, and the vibrant celebrations are emblematic of Brazil.
Santos, the biggest port in Latin America, was also closed due to winds that were over 55 km/h (34 mph) and waves that were over 1 m high, according to local media.
The affected areas would be visited on Monday, according to President Luiz Inácio Lula da Silva, who was spending the carnival weekend in the northeastern state of Bahia.
He expressed his condolences to those who had lost loved ones in a tweet and pledged to coordinate with law enforcement to send out medical teams and rescue crews.
All levels of government will be brought together, and with the help of the community, the injured will be treated, the missing will be found, and the region's roads, power connections, and telecommunications will be repaired, Mr. da Silva wrote.
Threatening to worsen the situation for rescue teams, more heavy rain is predicted in the area.
As the effects of climate change set in, extreme weather phenomena like the floods are anticipated to become more frequent.
More than 230 people were killed by torrential rain in the southeast city of Petropolis last year.
