Climatologia de ocorrências tornádicas no Sul do Brasil

The subtropical sector of South America east of the Andes, including southern Brazil, is frequently affected by severe convective storms. In some situations, atmospheric ingredients conducive to the occurrence of tornadoes are also observed. However, despite the potential for the formation of this hazardous weather phenomenon, the documentation of tornadoes in southern Brazil is poor compared to other regions around where consolidated severe weather databases exist (e.g., USA and Europe). This work leveraged different existing sources of information to generate a database of tornado occurrences covering southern Brazil, Uruguay, Argentina and Paraguay. These sources encompass tornado footage and photographs, or visual documentation of wind damage consistent with tornadic activity, available in traditional media and social networks. Additional sources include tornado events existing in the scientific literature and non-scientific initiatives that keep tornado reports. Tornado damage tracks identified through high resolution environmental satellite imagery were also included as a source of information. Such compilation produced a tornado database with 310 occurrences in southern Brazil. This study emphasizes the spatial, seasonal and annual distributions of the tornado occurrences in addition to the human impacts in terms of injuries and fatalities. The sector displaying highest frequency of tornado events was identified for an area encompassing northern Rio Grande do Sul, western Santa Catarina and southwestern Paraná states, with peak activity during winter.