By Steve Kingstone
BBC News, Sao Paulo
Southern parts of Brazil are experiencing some of the heaviest rainfall and flooding on record.
Flash flooding is becoming more common in Brazil's crowded cities
The country's commercial capital, Sao Paulo, has been worst hit with flash floods leaving many roads impassable and some parts of the city under water.
At least five people are known to have died, mostly as a result of mudslides triggered by the rain in the city's huge shanty-towns or favelas.
The city's rapid growth, outstripping its natural drainage, has been blamed.
City planners warned that flash floods could become increasingly common in the future.
Sao Paulo's city authorities said on Wednesday that 14cm (5.5in) of rain had fallen in Sao Paulo in the space of 24 hours.
The downpour is a record for this time of year, and is double the usual amount of rainfall for the entire month of May.
At one stage, the main river burst its banks, flooding a busy ring road and submerging cars and even buses.
Hundreds of thousands of people in outlying areas were unable to reach work in the city centre.
In the sprawling shanty towns that surround Sao Paulo, the rain caused fatal mudslides.
At both city and state level, Brazil's politicians are scrambling to assist the worst-hit areas and promising better drainage and flood relief channels.
But similar promises have been made in the past and more often than not, the funding has quickly dried up.