“Forget everything you’ve seen, it’s going to be much worse in the metropolitan region,” Governor Eduardo Leite said Friday as the streets of the state capital, with a population of some 1.5 million, started flooding after days of heavy downpours in the region.

The state’s civil defence department said at least 265 municipalities had suffered storm damage in Rio Grande do Sul since Monday, injuring 74 people and displacing more than 24,000 – a third of whom have been brought to shelters.

At least 68 people were missing, and more than 350,000 have experienced some form of property damage, according to the latest data.

And there was no end in sight, with officials reporting an “emergency situation, presenting a risk of collapse” at four dams in the state.

The level of the state’s main Guiaba river, meanwhile, was estimated to have risen 4.2-4.6 meters, but could not be measured as the gauges have washed away, the mayor of Porto Alegre said.

As it kept rising, officials raced to reinforce flood protection.

Porto Alegre’s worst recorded flood was in 1941 when the river reached a level of 4.71 meters.

Elsewhere in the state, several cities and towns have been completely cut off from the world in what Governor Leite described as “the worst disaster in the history” of Rio Grande do Sul.

Many communities have been left without access to drinking water, telephone or internet services.

Tens of thousands have no electricity.

President Luiz Inacio Lula da Silva visited the region Thursday, vowing “there will be no lack of human or material resources” in responding to the disaster, which he blamed on climate change.

The central government has sent aircraft, boats and more than 600 soldiers to help clear roads, distribute food, water and mattresses, and set up shelters.

School classes have been suspended state-wide.

“I feel very sorry for all those who live here… I feel pain in my heart,” Maria Luiza, a 51-year-old resident of Sao Sebastiao do Caí, some 40 miles from Porto Alegre, told AFP.

In Capela de Santana, north of the state capital, Raul Metzel explained that his neighbours had to abandon their livestock.