Dozens are still unaccounted for, and more than 5,000 have been displaced, according to the Sao Paulo Civil Defense Authority and the governor of Rio de Janeiro.
Brazil has been suffering from unusually heavy rains this year. February was the rainiest month for Sao Paolo since record-keeping began 77 years ago, according to the National Meteorological Institute.
And authorities warn that relief is not coming soon. After 72 hours of continuous rainfall, even more rain is expected, and authorities are asking communities to remain on high alert for possible mudslides.
Several cities in the coastal Baixada Santista region of Sao Paulo were severely affected, including Guaruja and Santos.
In Guaruja alone, 17 people were killed, including a firefighter in the rescue mission, CNN affiliate Record TV reported. About 200 people lost their homes, the Sao Paulo Civil Defense added.
Humanitarian aid has been delivered to Baixada Santista region, with mattresses, blankets, food and water being distributed to residents.
The governor of Rio de Janeiro, Wilson Witzel, expressed his condolences on Tuesday to the families of five victims who died in Rio de Janeiro, according to the State Secretariat for Social Development and Human Rights.
He also announced the creation of a relief fund for those affected by the floods, especially in the cities of Mage, Mesquita, Rio Bonito and Seropedica, where more than 5,000 people have been displaced.
The amount of rain that fell across Rio de Janeiro on Monday morning was equivalent to more than half the average for March, the city’s Operational Defense said. In Santa Cruz, it rained 6 inches in 32 hours, just less than the average for the entire month.
An ongoing storm system was seen over the coast and inland, the National Environmental Satellite, Data, and Information Service in the US said. The conditions will cause massive landslides, flooding and strong winds, the service warned.