Compounding and cascading disasters in Brazil

Compounding or cascading disasters, marked by the occurrence of multiple or consecutive hazards, lead to several impacts on both individual and collective levels, surpassing those of single-hazard disasters. Despite their severe consequences, global and regional impact databases still record disasters using a single hazard lens. This is the case of Brazil, which is confronted with intricate dynamics of overlapping hazards. To address this gap, we reclassified natural hazard-related disasters recorded in the Brazilian Integrated Disaster Information System (S2iD) database spanning 1991-2022 into different compounding and cascading disaster categories. We identified 2,236 co-occurring disasters, 30,913 spatially compounding disasters, and 1,338 temporally compounding disasters. A permutation test revealed expected significant co-occurrences, such as urban floods and landslides, droughts, and wildfires, alongside surprising pairings like droughts and cold waves. Using the apriori algorithm, we found significant event sequences, including wildfires followed by droughts, landslides after flash floods, and landslides preceding storms. Our analysis shows an increasing time trend in compounding and cascading disasters, predominantly occurring in regions northeast, south, and midwest. Notably, the impacts of these compounded disasters are greater than those of single-hazard events. These results underscore the need to integrate a multi-hazard perspective into disaster databases in Brazil and beyond. By accounting for the interactions between disasters, policymakers, and practitioners can design more robust adaptation measures that address interconnected risks.