Brazil is one of the countries with the highest incidence of tornadoes outside the regions traditionally known for such phenomena. According to a survey by the State University of Ponta Grossa (UEPG), between 1975 and 2018, a total of 581 tornadoes were recorded in the country, 411 of which occurred in the Southern Region, accounting for approximately 70% of all cases.
In 2018, the PREVOTS platform was established to document severe weather events across Brazil. Upon completing five years of operation, a report indicated that between June 2018 and June 2023, 321 damage incidents caused by tornadoes were recorded, including waterspouts. Most tornadoes in Brazil are associated with high-precipitation supercells, resulting in rain-wrapped tornadoes that are difficult to see.
The annual average number of tornadoes in Brazil remains uncertain due to the country's less robust meteorological infrastructure compared to nations like the United States or Canada, and because of the low population density in the most tornado-prone areas. These factors contribute to underreporting, with many tornadoes being identified only months or even years after they occur. Recent estimates suggest a plausible average of 50 to 60 tornadoes per year, although this figure lacks official confirmation due to the aforementioned limitations.
Climatology
Twenty-five of Brazil's 26 states have recorded at least one tornado since 1970, the only one without confirmation being the state of Acre. Even the Federal District has experienced tornado episodes, but most of them were landspouts. This is due to the tropical, semi-humid climate present throughout the country, but the southern states, the interior of São Paulo state in the Southeast, and southern Mato Grosso do Sul in the Center-West, are the most recorded, accounting for 95% of the country's tornadoes. This is because they are part of the "Pasillo de los tornados", a region of South America prone to tornadoes due to the meeting of warm, humid air masses from the Amazon rainforest, Gran Chaco, and the Atlantic Ocean, which meet cold, dry air masses from Patagonia and Antarctica, in addition to the hot, dry winds from the Andes mountain range. These areas are also influenced by severe convective storms from the Río de la Plata basin. A Harvard study revealed that the frequency of tornadoes in this alley is not even higher due to the ruggedness of the Amazon rainforest, which reduces vorticity near the ground. Although this region experiences a high number of severe storms throughout the year, this limitation significantly reduces the chances of tornado formation. Possibly, without this obstacle, the region could have a frequency equal to or even greater than that of North America.
However, a study on the development and intensification of mesocyclones in rough environments showed that neither very high nor very low roughness levels can favor the intensification and development of the mesocyclone. Furthermore, even environments with high roughness still produced tornadoes, although generally weaker ones. In other words, roughness is not the main factor behind the low incidence of tornadoes in regions with a high incidence of severe storms; what actually happens is that the available research on the subject is still not very robust.
In the summer, the eastern part of the state of Santa Catarina, where most of the coastline is located, is an area more prone to convective storms due to orographic forces. Consequently, tornadoes can occur.
In the fall, despite a lower density function of events, records are still notable between the states of Paraná and Santa Catarina, also extending towards the state of São Paulo (SP), where, in this season, the infamous F3 tornado of Indaiatuba occurred in May 2005.
In the winter, the KDE map has a density in the center and east of the state of São Paulo and in all the states of the South, with a higher concentration in the north of Rio Grande do Sul and west-central Santa Catarina. The intense baroclinicity during the winter is responsible for the increase in JBN episodes. In addition, the presence of intense flow at low levels associated with the JBN contributes to intensifying shear at low levels. A curious fact is that, during this period, the number of tornadoes decreased in the southwest and far south of Rio Grande do Sul. However, the low population density may be the reason.
In the spring, these regions with fewer occurrences see an increase in frequency, but still in smaller numbers than in northern Rio Grande do Sul. At this time, the Hotspot (northern Rio Grande do Sul) weakens and moves further west in the state.
El Niño years (positive ENSO) are frequently more active, as was the case in 2009, which had at least 19 events, with an outbreak in western Santa Catarina, including a deadly F4 tornado in the municipality of Guaraciaba. On August 13 and 14, 1959, an outbreak of at least 10 tornadoes, including F4+ tornadoes, struck southern Brazil, killing more than 100 people. Other examples include the years 1965, 1987, 1991/92, 1997/98, 2005, 2015/16, and 2023, where there were also many events, including notable occurrences. On the other hand, the rainy seasons, especially in spring, have records slightly below average.
On the other hand, La Niña seasons, especially in the spring, have records slightly below average. Neutral years, however, have records within their normal flow. This cited study focused on older events, so the number of records tends to be lower than the current one, as we used convincing newspaper reports and satellite images, whenever possible, for records after 1960.
Tornadoes in this alley are comparable to Dixie Alley, with HP supercell tornadoes being more common, and the terrain is more undulating, with one exception in the Pampas. Furthermore, nocturnal tornadoes or outbreaks are more common, as was the case with the outbreak on the night of September 7, 2009, in the province of Misiones, Argentina, and southern Brazil. Tornadoes generally range from F0 to F2, but some violent and deadly tornadoes have occurred, such as an F5 in San Justo, Argentina, in 1973; an F5 in Encarnación, Paraguay, in 1926, with over 300 deaths; an F4 in Fray Marcos, department of Florida, Uruguay, in 1970.
Events This list only has records documented and cited in reliable articles.
Total count </onlyinclude> Note: 243 tornadoes have been confirmed but not yet rated. Note: Some tornadoes have been rated using different scales. They are counted as their closest F-Scale equivalent on this table.
Pre-1950 September 14, 1921 – A tornado struck the town of Chavantes, in the state of São Paulo, causing much destruction. The tornado destroyed brick homes, uprooted power lines and fences, damaged farms, and destroyed crops. In total, seven people died and many were injured. Several animals were also killed. At the time, the event was called a cyclone, but the characteristics of the reports indicate it was a tornado. October 24, 1927 – A multi-vortex tornado struck the city of Ponta Grossa in Paraná State, causing many destruction, killing 3 people and injuring severe others. The tornado was officially classified as E/F2. May 21, 1938 – A severe/violent and deadly tornado struck the Atuba neighborhood in Curitiba, in Paraná. Houses were completely destroyed. One was thrown 50 meters, according to a newspaper at the time. Another house, 7 meters in size, disappeared from the map. Many animals died, including pigs, cows, and oxen; some were sucked from their pens. Trees were uprooted and apparently "flattened," according to reports from the time. Crops suffered severe devastation. A brickyard had a large part of its structure collapse. A pipe factory was destroyed, resulting in enormous material and financial losses. The newspaper classified the tornado as an F4. The tornado, dubbed "The Gale of Death" by a newspaper, killed 18 people and injured at least 50. https://www.tribunapr.com.br/noticias/curitiba-regiao/tornado-fortissimo-atingiu-a-grande-curitiba-em-1938-e-virou-manchete-historica/#google_vignette May 16, 1948 – A violent nighttime tornado struck Valinhos, in the interior of the municipality of Canoinhas, in Santa Catarina. Several homes, a school, and a church were completely destroyed. A sawmill was also destroyed, and the wooden planks located there were turned into projectiles, resulting in fatal injuries to animals and people. Many of these projectiles were embedded in trees. In addition, other trees were uprooted and left without bark. People were found far from their homes, many already dead, and some of them naked. Eighteen people died instantly, and another five died in the hospital (23 deaths in total). Officially, the tornado was classified as an F3, with winds estimated at 300 km/h (186 mph). However, much of the damage is consistent with an F4 tornado, and many storm chasers consider it to be of that intensity.
1950–1959
May 18, 1955 – A strong tornado struck Serra das Mortes, in the interior of Canoinhas. Wooden houses were destroyed and thrown into the air. The tornado injured at least four people. Another tornado may have struck Papanduva, resulting in the destruction of homes and nine deaths. May 1957 – A tornado measuring 300 to 400 meters (984 to 1,312 ft) wide destroyed farms and buildings from Guarapuava to Cascavel, Paraná, in addition to uprooting trees and piling them on top of each other. The tornado left a visible and well-defined path, possibly an F3+ or higher. April 25, 1959 – A strong tornado struck the municipality of Aratiba, in Rio Grande do Sul. 56 houses were affected, with 33 being completely destroyed. A school building was damaged, and forested areas were devastated. It traveled approximately 40 km (24.8 mi) and devastated the west–east part of the municipality. In addition, the tornado may have also hit the neighboring municipality of Erechim, causing further extensive damage to crops. In total, 10 people died, 104 were injured, and almost 200 were left homeless.