On Sunday, July 15, the southern region of Brazil braced for the impact of Ciclone Subtropical Biguá, which has been generating significant winds and rainfall throughout the area. The Brazilian Navy officially confirmed the cyclone’s formation on Saturday evening, noting its infrequency and unusual nature for the region.
Biguá, which is the first subtropical cyclone to affect Rio Grande do Sul since May 2022, was characterized by gusts between 70 and 100 kilometers per hour, with some localized areas even experiencing winds as high as 120 kilometers per hour, especially near Lagoa dos Patos. "Our forecasts indicate the cyclone will begin moving away from the coast by late Sunday afternoon," explained meteorologist Fernando Rafael.
The cyclone has also caused widespread heavy rain, with expected totals ranging from 30 to 100 millimeters, which raises concerns about flooding and electrical outages. According to the National Institute of Meteorology (INMET), the cyclone poses significant dangers, including damage to buildings, uprooting trees, and interruption of electricity supply. By Saturday evening, the heavy winds prompted the closure of the Port of Rio Grande.
"This cyclone is rare as it differs from the extratropical systems we typically see here," stated Rafael, emphasizing the unique structure of subtropical cyclones. He remarked, "While extratropical cyclones are fed by cold fronts and temperature differentials, subtropical systems have warm, vertical elements as well. Their effects can be quite similar, producing fierce winds and substantial rainfall."
Biguá received its name following the Brazilian Navy’s tradition of naming atypical cyclones after local fauna, with the name stemming from Tupi, meaning the sea bird.
According to INMET alerts, the most affected areas include the southern and eastern parts of the state, with towns such as Santa Vitória do Palmar, Chuí, and Pelotas on high alert for strong winds and heavy rains. These warnings, marked by 'red alert' status, predict accumulation levels exceeding 100 mm/day and winds surpassing 100 km/h.
The forecast warns of potential structural damage, power outages, and flooding, resulting from the intense weather based on historical data leading to similar incidents. Esteemed meteorologist Estael Sias remarked, "The storm may weaken slightly as it approaches central regions but could still produce significant gusts of wind throughout the area."
The cyclone is making its way through the center and east of Rio Grande do Sul, impacting urban areas like Porto Alegre as it advances. Residents are urged to take precautions such as securing loose items outdoors, staying informed through local weather updates, and avoiding unnecessary travel.
Also significant is the enhanced risk from high sea waves, with predictions indicating waves of up to four meters along the southern coast of Brazil as the cyclone developments continue. Maritime activities are advised against due to the potential dangers posed by these conditions.
"We have to monitor these storms closely," noted the Brazilian Navy, emphasizing the importance of staying alert and adhering to guidelines provided by local authorities. The expected transition of the cyclone from subtropical to tropical depression is predicted as it loses strength upon encountering the cooler waters of the Atlantic.
Despite the storm’s decrease in wind force as anticipated for Monday, severe conditions may still persist for residents of Porto Alegre and the surrounding areas. The population is notified to maintain caution, particularly concerning falling branches and localized flooding.
Weather experts from MetSul Meteorologia, who had previously alerted about the cyclone's potential, continue updating the public on real-time developments and safety recommendations. Meteorologists stress the importance of preparedness, especially when facing atypical weather systems like Biguá.
With vigilance needed, the Defense Civil's recommendations are clear: monitor alerts, avoid travel, and safeguard homes and properties against possible damage caused by fierce winds and rain.
Weather conditions will remain unstable throughout the day but are expected to clear significantly by Monday, as Biguá drifts toward the sea. Prior cyclones such as Yakecan, which had devastating effects on the region, serve as reminders of the potential severity of these weather phenomena and the importance of thorough preparation.
Overall, as Ciclone Subtropical Biguá continues to affect southern Brazil, authorities remain on high alert, ready to respond to the needs of residents and minimize risks associated with this powerful storm.
