University of São Paulo: Tragedy on the north coast of São Paulo was not unexpected and could have been avoided

The anomalous volume of rain that hit the north coast of São Paulo last weekend has already left, until the last update, 54 victims , about 30 missing and more than 4,000 homeless. São Sebastião is the municipality most affected and the one with the most deaths. The National Center for Monitoring and Natural Disaster Alerts (Cemaden) had already issued an alert for heavy rains on Friday (17) to the federal government and the Military House of São Paulo, responsible for Civil Defense.

The National Institute of Meteorology already had information that heavy rains were going to happen on Thursday (16). “This event was not an event classified as unexpected and unusual from a forecasting point of view; it was planned at least 24 hours in advance”, says Pedro Luiz Côrtes, full professor at the School of Communications and Arts and the Institute of Energy and Environment, both at USP. This opens, in theory, a window of action.


The professor says that meteorological models already indicated that there would be a volume of rainfall between 200mm and 250mm, generally what is expected for a month, in just 24 hours. Others indicated 400mm, far beyond normal for just one day. However, the volume reached almost 700mm, the largest in the country’s history in just one day, according to data from Cemaden.

According to him, when meteorological models present a forecast as exceptional as this one, it is important to verify whether or not the other models confirm the emergency situation, as well as the quality of the information. He says that all indicated a critical situation for the coast, even if the volume of rainfall varied. All of this becomes more critical considering the precarious housing structures found in that region.

The governor of the State, Tarcísio de Freitas, warned that tourists should not travel to the north coast, so as not to overload services. The Civil Defense has already issued an alert for the continuation of heavy rains in the area in the coming days.

Was the population alerted?
The director of Cemaden, Osvaldo de Moraes, said in an interview that the agency had already warned the Civil Defense and the government of the State of São Paulo about the critical situation due to the volume of rain expected for the north coast. In other words, the tragedy could have been avoided. Cemaden, detecting the alert, notifies the Civil Defense of the States, which can notify the Civil Defense of the municipalities. There is the possibility of Cemaden directly notifying the monitored municipalities. Its function is to monitor risk areas.


Civil Defense, in turn, upon receiving this diagnosis, can send messages via SMS to the local population to warn them of the forecast of rains, floods and landslides. The big problem, highlighted by Côrtes, is that only people registered for the service receive the SMS. Many people are not even aware of the existence of this service.

Those who received the SMS, however, were unaware of the seriousness of the problem. This is because the messages are very generic. The first message sent by the Civil Defense, on Friday (17), said: “Isolated rain in the Ubatuba region. Has condition for lightning. Hits nearby areas. Seek shelter”. The content of the messages is designed so that the population does not panic, however, it leaves them misinformed. An alert issued on Sunday morning (19), when people were already missing and buried, said: “Persistent rain on the north coast. There’s wind and lightning. Reaches neighboring cities. In case of different inclination of the walls, leave the place”.

Another problem is: even informing people of the seriousness of the problem, where would they go? “The result we are reaping includes the lack of information: if people were informed, many people could avoid going to the coast. So, the flow of tourists on the coast would already be reduced and people who live [on the coast] could seek shelter, even if on their own, which would not be ideal”, says the professor. In a scenario in which people who live or were on the north coast were properly alerted, they could have gone in search of shelter, or, at least, remained in a state of extreme alert.


“Receiving the SMS does not have to be optional, it has to be mandatory. The telephone companies have to send a precise message, informing ‘look, we have such a situation predicted for that municipality’, and send it to all the people who are in that region”, says Côrtes. Unfortunately, the whole tragedy was made worse by a very large displacement of tourists – who frequent the region throughout the year – due to the Carnival holiday. “It was very evident that the communication structure for the population does not work”, he concludes.

For the professor, “it is essential that the Civil Defense of the State count on the collaboration of the press, because they would certainly issue this alert”. Another solution would be for the State Highway Police to stop cars, recommending that people not go to the coast.

Can this be repeated?
There is still rain forecast for the end of this month and the beginning of March, but not in the same volume that fell on the weekend of the tragedy. The warning sign remains, however, as waterlogged soil and exposed areas must be taken into account. “This greatly increases the damage potential caused by this rain”, says the professor.

Heavy rains have become increasingly frequent due to climate change and may occur again on the coast or even in the city of São Paulo. “Climate no longer behaves as it did in the last century, when the general level of predictability was higher. We are unlikely to have rainfall like this outside of this pattern”, he explains.

Unfortunately, these extreme phenomena can happen again. “It is necessary that we, as a society, have a very attentive look to demand from politicians solutions that reduce the level of exposure of the population in general”, he concludes.