Rafael Adriano Peres could hardly move as he lay on a mattress in a refuge center in Porto Alegre, after being hit by a car when historic floods swept southern Brazil this month.

The 35-year-old suffered two broken ribs but couldn't return home from hospital as water had filled the property he shares with his wife.

"We don't know what tomorrow will bring. We have to start from scratch," said Peres, who worked in waste management in Porto Alegre which is now largely submerged after the Guaiba River burst its banks.

Surrounded by a mountain of donated clothes and toys, almost 800 people were staying in this large hangar Sunday in the capital of Rio Grande do Sul.

The state has been gripped by a climate catastrophe for almost three weeks which has killed more than 150 people and left around 100 missing.

Only getting worse

Some people plan to return to their homes once the high waters subside but others like 50-year-old Marcia Beatriz Leal, who has suffered three floods, have already given up that hope.

"You fight to get it all back and then it's gone again," said Leal, who lived in a rented home in the flood-hit town of Estrela.

She spoke to AFP with her seven-year-old son Pietro and her mother, who suffers from Alzheimer's disease, sleeping next to her.

Leal, who makes clothes for pets, said she felt better after crying at a talk in the shelter organized by the city council's mental health service.

She hopes to move to another area with her mother and son, hopefully sheltered from increasingly intense rains in the region that scientists say are linked to climate change and the El Nino weather pattern.

"This is nature giving back to us what we do to it," Leal said.

Huddling in colorful blankets next to Leal, Peres agreed: "It's human beings who are destroying our planet. It's only going to get worse."

He worries other cities in Brazil could face similar flooding, pointing out his concerns in particular about deforestation in the Amazon.

Life goes on

Some 13,000 people have taken refuge in the 149 facilities in Porto Alegre, a city of 1.4 million inhabitants, according to local authorities.

Those worst affected may face a lingering fear of floods returning, but most will overcome that feeling, said psychologist Marta Fadrique, who leads the city's mental health service.

Problems can include anxiety, insomnia and paranoia, she told AFP outside the center, where clothes dry in the sun and children run around, seemingly oblivious to the tragedy.

Venezuelan cleaner Habraham Elises Gil, 25, left his country six years ago due to its economic troubles and rebuilt his life in Porto Alegre with his wife and two children.

He lost everything in the floods but is already thinking about starting over.

"The children give us strength. Life goes on. As long as we are alive, everything has to go on," Gil said.