On June 30, 2020, Southern Brazil faced one of the most severe mornings in its recent history due to the passage of bomb cyclones. Wind gusts exceeding 100 km/h resulted in 13 deaths, left nearly 3,000 people displaced, and caused power outages in areas of Rio Grande do Sul, Santa Catarina, and Paraná.
This disaster was attributed to the phenomenon known as bomb cyclones, or bombogenesis, which occurs from the accelerated meeting between large masses of hot and cold air. This process involves a cycle of air heating and rising, followed by cooling and sinking, a movement called convection. This repetition generates a sudden decrease in atmospheric pressure at the center of the system, which gives the cyclone its rapid strength, justifying the name 'bomb.'
Several municipalities were impacted by the passage of this cyclone that year. In Santa Catarina, cities such as Florianópolis and Balneário Camboriú suffered destruction caused by the phenomenon.
Santa Catarina was the most affected state, recording 11 confirmed deaths. Data from the Regional Civil Defense Coordinators on the day of the event pointed to 25 affected municipalities, a number that increased to 184 municipalities, representing 62% of Santa Catarina's cities. In Chapecó, a 78-year-old woman died after being struck by a tree. In Santo Amaro da Imperatriz, a pedestrian did not survive after being hit by high-voltage wires resulting from a fallen tree.
The subsequent early mornings required the Santa Catarina Government to declare a state of public calamity. On July 1, winds reached 90 km/h, and 369,600 residences remained without power for more than 24 hours after the first blackout.
In Rio Grande do Sul, the bomb cyclone left 2,331 people homeless or displaced in 23 cities, due to flooding and strong winds. In Porto Alegre, although the gusts were milder, around 80 km/h, there was falling poles and trees, blockage of at least 28 roads, and structural damage to buildings.
In Paraná, the cyclone caused damage in at least 84 of the 399 municipalities, according to the Civil Defense report, and registered at least one death. In Curitiba, winds close to 100 km/h knocked down trees and left 193,000 properties without electricity.
The effects in the Southeast were milder, as the cyclone only touched the state of São Paulo during its trajectory in the region.
Concern about the arrival of new bomb cyclones is high, especially in the South regions and parts of the Southeast, considering the year 2026. In South America, these extratropical cyclones generally originate in the ocean, near the coasts of Argentina and Uruguay. The 2020 episode started near Paraguay and followed the southern Brazilian coast, dissipating into the sea.
With global warming, there is a trend for the impacts of bomb cyclones to become more intense. This occurs because the increase in temperature in the oceans and atmosphere tends to accentuate the contrast between the hot and cold air masses that cause the phenomenon. It is relevant to note that the cyclone preceding the 2020 one, which occurred in 2016, was less severe. Furthermore, a report from the World Meteorological Organization (WMO) points out that humanity is experiencing the ten hottest years in its recent history.
After a series of storms, wind gusts, and other intense weather events recorded in various areas of Brazil recently, the question arose as to whether El Niño is responsible for these occurrences. Experts consulted by Olhar Digital indicate that the climate phenomenon has already begun to affect the country, however, it is not the only explanatory factor.
