Footage from São Paulo on Monday was shocking. Cars being swept away by rushing streams, trees ripped from the ground, people rescued with jet skies in areas usually full of rush-hour traffic, subway stations being shut down. It seems that every summer we tell the same story about how tropical storms—which always come this time of year—have caught local authorities off guard and caused human tragedies and material losses. A month ago, six people died after floods in Rio de Janeiro. Now, 12 people have died in Greater São Paulo.
The city’s administration claims that Monday’s rains accounted for 90 percent of the volume expected for the entire month and that nothing could have been done to prevent the damage. This is only partially true. Indeed, this week’s rainfall was exceptional, and Monday saw the second-highest amount of rain in one day since 1995. While several of the city’s neighborhoods are geographically wedged in valleys, floods are a decades-long problem and could have been corrected—or at least mitigated—by now.