Chuvas sem precedentes de abril a maio de 2024 no Sul do Brasil definem novo recorde

Walter Collischonn; Rafael Cabeleira; Nicole Ramalho; Anderson Ruhoff; Rodrigo Paiva; Fernando Fan; Sly Wongchuig; João Breda

doi:10.1590/SciELOPreprints.9773

##article.authors##

Walter Collischonn Universidade Federal do Rio Grande do Sul https://orcid.org/0000-0002-7630-396X
Rafael Cabeleira Universidade Federal do Rio Grande do Sul https://orcid.org/0009-0008-6835-4047
Nicole Ramalho Universidade Federal do Rio Grande do Sul
Anderson Ruhoff Universidade Federal do Rio Grande do Sul https://orcid.org/0000-0002-3585-2022
Rodrigo Paiva Universidade Federal do Rio Grande do Sul
Fernando Fan Universidade Federal do Rio Grande do Sul https://orcid.org/0000-0003-0371-7851
Sly Wongchuig Laboratoire d’Études en Géophysique et Océanographie Spatiales https://orcid.org/0000-0002-1116-0742
João Breda Wageningen University & Research https://orcid.org/0000-0002-8360-1308

DOI:

https://doi.org/10.1590/SciELOPreprints.9773

Keywords:

rainfall, flood, record rainfall, extreme rainfall, depth-area-duration

Abstract

This technical note presents a comparative analysis between the heavy rainfall that occurred in Rio Grande do Sul, between April and May 2024, with the heaviest rainfall events ever observed in Brazil, between 1961 and 2022. The comparative analysis was performed using the Depth Area Duration technique, suitable for the analysis of heavy rainfall on a large spatial and temporal scale. We concluded that following our analysis, the rainfall that occurred in Rio Grande do Sul largely exceeded the most intense large-scale precipitation events historically observed in Brazil, from 1961 to 2022, at least for areas from 2,000 to 100,000 km² and rainfall durations of 3 to 14 days. In some cases (3-day rainfall in 10,000 km²) the 2024 rainfall was 47% higher than the previous record rainfall. Considering that we cannot rule out that similar events occur in any other basin, at least in South Brazil, it may be necessary to review the original design and operation rules of high-risk hydraulic structures and flood defense systems throughout the Southern region of the country.