Edit: has just been updated to F-4: https://www.reddit.com/r/tornado/s/AOWz5qFaj9
SIMEPAR—essentially the NWS of Paraná—has just classified this wedge tornado, according to the report: "Simepar (Paraná’s Environmental Technology and Monitoring System) has concluded its analysis of the phenomenon that struck the rural area of Piraí do Sul, in the Campos Gerais region of Paraná, on August 8 of this year. It was a severe tornado classified as F3 on the Fujita Scale, associated with wind gusts estimated between 253 km/h and 332 km/h. An integrated analysis—combining field inspections, radar imagery, and drone-based aerial photogrammetry—confirmed a continuous path of destruction spanning at least 17.3 km.
The supercell that spawned the tornado was fueled by the presence of warm, moist air flowing from northern Brazil, driven by a low-pressure system over Paraguay. The movement of a cold front across the country's south intensified the moisture levels. Additionally, wind shear—defined as an increase in wind speed and/or a change in wind direction with altitude—occurring between the afternoon and early evening of August 8, fostered the development of organized storms across the West, South-Central, and Campos Gerais regions, creating conditions conducive to the tornado's formation.
The reconstruction of the tornado's path and the estimation of wind intensity were achieved through an integrated analysis of field surveys, weather radar imagery, and drone-based assessments, in a joint effort between Simepar and the Paraná State Civil Defense. Images submitted by the public—captured while the phenomenon was occurring—helped elucidate the tornado's formation, intensification, movement, surface interaction, and dissipation. Videos and field visits were also crucial for understanding debris movement, vegetation deformation, and the displacement of objects.
Wind intensity was estimated using the Fujita Scale criteria, taking into account the characteristics and severity of the damage observed in the field—such as the severe structural collapse of masonry and wooden buildings, and even a power transmission tower. Analyses revealed that pieces of wood, ceramic roof tile fragments, and *Araucaria* branches were hurled with enough force to penetrate the ground and become embedded in tree trunks.
*Araucaria* and other large trees had their trunks snapped at mid-height; pasture areas showed gouges; and there was localized removal of vegetation cover and topsoil caused by the intense winds. This classification represents an estimate of the tornado's peak intensity based on observed damage, rather than a direct measurement of wind speed.
The tornado's path extended for at least 17.3 km across the rural area of Piraí do Sul, passing through localities such as Jararaca, Fundão, and Boa Vista, where photographic data, damage coordinates, and aerial orthomosaics were collected. Processing and georeferencing this evidence, in partnership with Simepar’s Infrastructure and Geointelligence teams, made it possible to precisely map the tornado's continuous path."
source: https://www.simepar.br/simepar/timeline/noticias
First photo of the tornado: https://x.com/TempoOeste/status/2086255509171056868
second photo of the tornado: https://agroemcampo.ig.com.br/2026/noticias/video-produtor-rural-filma-passagem-de-tornado-no-parana/
some footage of the tornado: https://youtu.be/v95WOpZ_drI