Simepar final technical report upgrades the classification of tornadoes that struck 11 municipalities in Paraná

Simepar: “Paraná environmental technology and monitoring system” concluded this week the technical report detailing the trajectories and classification of the three tornadoes that struck Paraná on November 7. 

The work described in the document, which exceeds 130 pages, upgraded to F4 on the Fujita Scale the tornadoes that struck Rio Bonito do Iguaçu and Guarapuava, and maintained the F2 classification for the tornado that struck Turvo. Eleven municipalities were affected: Rio Bonito do Iguaçu, Turvo, Guarapuava, Quedas do Iguaçu, Espigão Alto do Iguaçu, Nova Laranjeiras, Porto Barreiro, Laranjeiras do Sul, Virmond, Cantagalo, and Candói.

The report describes the analyses carried out through the integration of operational meteorology, geointelligence, remote sensing, and geospatial analysis. The work involved all departments of Simepar, with support from the Fire Department, the Water and Land Institute, and the Paraná State Civil Defense, enabling a comprehensive understanding of the event and providing valuable input for territorial planning and risk management. It concluded that this event can be considered one of the largest of its category in the State of Paraná over the past 30 years, considering the number of tornadoes within the same event, the number of people affected, and the multi-level destruction observed along their paths.

The conclusion was that the cold branch of an extratropical cyclone formed over southern Brazil favored the development of high-intensity storm clouds over Paraná on November 7. Some of these clouds, embedded in an environment of high thermodynamic instability, intensified further, evolving into supercells with rotational characteristics around their vertical axis. Strong vertical wind shear and the transport of warm, moist air were crucial to the storms’ evolution.

Two of these supercells were responsible for the occurrence of three tornadoes in municipalities in the Southwest and Central-South regions of Paraná. The categorization of the tornadoes followed the methodology established by the Fujita Scale, which was created to measure the intensity of the phenomenon based on observed damage and estimated wind speeds.

Evidence of damage was obtained through photographic records made by meteorologist Reinaldo Kneib during helicopter overflights of the area between Espigão Alto do Iguaçu, Rio Bonito do Iguaçu, and Virmond, as well as in the Entre Rios district of the municipality of Guarapuava, during the two days following the event. He also conducted surface-level photographic surveys in the urban area of Rio Bonito do Iguaçu, and the team additionally analyzed images, videos, and testimonies provided by third parties.

“That is why Simepar exists: so we can work on mitigation and also on future resilience that will be built from the experience of this tragic episode,” says the State Secretary for Sustainable Development, Rafael Greca.

The first supercell generated Tornado 1, which passed through Quedas do Iguaçu as an F1, Espigão Alto do Iguaçu as an F1, Nova Laranjeiras as an F1, Rio Bonito do Iguaçu as an F4, Porto Barreiro as an F3, Laranjeiras do Sul as an F3, Virmond as an F2, and Cantagalo as an F1.

This same supercell also generated Tornado 2, which passed through Candói as an F2 and through the Entre Rios District in Guarapuava as an F4. The supercell traveled approximately 270 km, with an average translational speed of about 80 km/h.

A second supercell traveled approximately 230 km, with an average translational speed of about 85 km/h, and generated Tornado 3, which passed over Turvo as an F2.

On the Fujita Scale, F1-category tornadoes are of moderate severity, with estimated wind speeds between 116 km/h and 180 km/h. F2 tornadoes have considerable severity, with estimated wind speeds between 180 km/h and 253 km/h. F3 tornadoes are considered severe, with estimated wind speeds between 253 km/h and 332 km/h. F4 tornadoes are considered devastating, with estimated wind speeds between 332 km/h and 418 km/h.

The scale ranges from F0 to F5, where F0, with light severity, has winds between 65 km/h and 116 km/h, and F5 is described as “incredible,” with winds between 418 km/h and 511 km/h.

Tornado 1 traveled approximately 75 km, with an estimated impact area of 12,426 hectares. Its width varied from 750 meters in Quedas do Iguaçu to 3,250 meters in the region of greatest intensity, in Rio Bonito do Iguaçu. On average, the width was 1,850 meters, reflecting the destructive power of the tornado, especially in the most affected areas.

The F4 intensity of Tornado 1 occurred in the urban area of Rio Bonito do Iguaçu, causing massive destruction to buildings, the tossing of vehicles, the overturning of a truck, and damage consistent with wind speeds compatible with this category.

For Tornado 2, in Guarapuava, the damage was also consistent with the F4 category, including intense and widespread destruction of vegetation at multiple points, the total collapse of some masonry houses, and even the displacement of a shipping container by approximately 150 meters. Tornado 2 traveled about 44 km, with an estimated impact area of 2,301 hectares. Its width was more homogeneous, ranging between 500 meters and 1,160 meters.

Tornado 3 had the shortest path, extending 12 km with an impact area of 570 hectares. Its width ranged between 400 meters and 675 meters, with an estimated average of 525 meters.

As soon as the weather forecast confirmed the occurrence of severe storms on the previous Tuesday, the 4th Simepar began issuing daily bulletins to the public. In partnership with Civil Defense, teams reinforced monitoring of the regions expected to be most affected. On Friday, the 7th, a special operation involving all meteorologists in Curitiba monitored atmospheric conditions in real time.

When the phenomenon was confirmed in Rio Bonito do Iguaçu, around 6:10 p.m., preliminary analyses for tornado classification began. The first photos and videos taken by rescue teams in the municipality and forwarded by Civil Defense already indicated the tornado’s potential.

After analyzing radar data, reflectivity was studied, and a hook echo was also identified—an indication on meteorological radar that suggests the possible presence of a tornado. Initially, the tornado was preliminarily classified on the Fujita Scale between F2 and F3, with estimated winds around 250 km/h.

The following morning, Saturday, the 8th, Reinaldo Kneib, meteorologist at Simepar, went to the city to conduct technical interviews. Accompanied by a Fire Department member trained in Civil Engineering, he also carried out helicopter overflights of the city and other regions where radar data indicated a possible tornado. Reinaldo spoke with professionals involved in rescue operations across all affected municipalities, as well as with residents from the impacted areas. He directly assessed the distances that objects and people were thrown by the force of the wind.

A meeting involving all 15 meteorologists from the Curitiba team concluded, after extensive debate, the analyses carried out for the issuance of a technical note, which already identified the two supercells that generated the three tornadoes. Initially, the Rio Bonito do Iguaçu tornado was classified as F3, the Guarapuava tornado as F2, and the Turvo tornado also as F2.

Work continued in the following weeks, involving other departments of Simepar. Meteorological analyses based on satellite and radar imagery were corroborated by the combined use of satellite images and aerial imagery, which were essential for identifying macro-scale landscape changes and more specific damage patterns. Multispectral analysis helped delineate the tornado tracks.

“The integrated approach strengthens response and mitigation capacities in the face of extreme climate events and is an important step toward building a more efficient and resilient risk management system in Paraná,” says Paulo de Tarso, CEO of Simepar.