Cyclone Activity in the Southern Hemisphere: February 2025 Summary

In late February 2025, multiple tropical cyclones were active in both the South Pacific and Indian Ocean, evidenced by satellite imagery. Cyclone Rae was weakening, while Alfred and Seru posed potential hazards to southern Queensland. Off Western Australia, Cyclone Bianca had weakened, whereas Honde and Garance threatened land, particularly Mauritius. Warm sea temperatures have heightened the likelihood of severe storms this cyclone season.

In late February 2025, the South Pacific and Indian Ocean were simultaneously home to an unusual number of tropical cyclones. Notably, five storms were visible in a false-color image captured on February 26 by the VIIRS sensor onboard the NOAA-20 satellite. This image highlights the infrared brightness temperature, distinguishing cooler cloud structures from the warmer ocean surface beneath.

On the day prior to the image, Tropical Cyclone Rae was dissipating to the east after causing heavy rainfall in Fiji. In the South Pacific, Cyclones Alfred and Seru were also present; Seru briefly reached Category 1 strength while remaining offshore of Australia. Meanwhile, Cyclone Alfred, categorized at Level 2 then, was projected to strengthen to Category 4 soon, posing significant risks to southern Queensland.

Off Western Australia, Cyclone Bianca was concluding its path, having weakened to a tropical storm by February 26. Previously, it had escalated to Category 3 but remained far enough from the land to minimize potential impacts. In contrast, Cyclones Honde and Garance in the Indian Ocean were more threatening, with Mauritius closing its airport due to Cyclone Garance’s imminent approach, poised to strengthen from Category 2 to Category 3.

Meteorologists point to the coinciding warm sea surface temperatures and low wind shear as factors encouraging the development of these storms. Since September 2024, a marine heat wave has persisted near Western Australia, resulting in significantly higher sea temperatures. The Australian Bureau of Meteorology has predicted an elevated probability of severe tropical cyclones this season, emphasizing that the tropical cyclone season in the Southern Hemisphere traditionally occurs from November to April.

The occurrence of multiple tropical cyclones in both the South Pacific and Indian Ocean during late February 2025 illustrates unusual storm activity driven by warm sea conditions. While Cyclone Rae was weakening, Cyclones Alfred, Seru, Bianca, Honde, and Garance posed various degrees of threat to surrounding regions. Meteorological predictions suggest increased cyclone activity for the remainder of the season.

Original Source: earthobservatory.nasa.gov