Floods in Brazil are becoming increasingly frequent and intense, posing a challenge to populations and government officials who are facing environmental, social and technical obstacles in an attempt to reduce their impact. Many people in Brazil are exposed to conditions of vulnerability that increase the impact of floods, combining social, environmental, political, economic and cultural aspects. This characteristic of floods in vulnerable contexts makes it difficult to separate what is natural from what is social in this type of event. I dedicate this work to all the families, men and women, children and young people who have lost their relatives, their homes, their belongings and their well-being, both psychological and material, due to the floods. I hope that all the suffering they have experienced will serve as an incentive for a worldwide mobilization to rescue solidarity, human ethics and the eco-sustainable development of our planet.