Global warming exacerbates these phenomena and intensifies the effects between such systems, making weather unpredictable, said Marcelo Schneider, a National Meteorology Institute (Inmet) researcher.
Electricity cuts
In Porto Alegre, a city of 1.3 million inhabitants, downtown streets were underwater after the Guaiba River breached its banks with record water levels.
Residents faced empty supermarket shelves and closed petrol stations, with shops rationing sales of mineral water. The city distributed water in trucks to hospitals and shelters.
Airport runway light towers are partially submerged after heavy rains in Porto Alegre.Credit: AP
The floods have also impacted water and electricity services, with more than 1.4 million affected overall, according to Civil Defence.
Loading
Almost half a million people were without power in the capital and outlying towns as electricity companies cut off supplies in flooded neighbourhoods for security reasons. National grid operator ONS said five hydroelectric dams and transmission lines were shut down due to the heavy rains.
The city’s airport, its apron underwater, has suspended all flights since Friday.
Fuel shortages were reported as state-run oil company Petrobras said it was having trouble moving diesel from its refinery in badly flooded Canoas within metropolitan Porto Alegre, a senior government official said.
President Luiz Inacio Lula da Silva said on a government television program that the extent of the damage would not be known until the waters subsided. He promised federal aid for the state in what is considered its worst ever climate disaster.
JP Morgan economists projected that the impact of the floods on the Brazilian economy would be a modest dent in GDP growth and a marginal increase in inflation, mainly due to higher prices for rice that is largely produced in Rio Grande do Sul. The government said Brazil would import rice to stabilise the market.
Loading
Besides destroying critical infrastructure, the heavy rains and flooding have left grains fields underwater and killed livestock, interrupting the soy harvest and halting work at multiple meat plants.
The Rio Grande port, a major port for grain exports, was operating normally, the state’s port authority said. However, main access roads were impassable, disrupting grain deliveries to the port as trucks had to make a wide detour, exporters said.