Cyclone Activity in the Southern Hemisphere: February 2025 Overview

In late February 2025, the South Pacific and Indian Oceans experienced simultaneous activity of six tropical cyclones. Tropical Cyclones Alfred, Seru, Bianca, Honde, and Garance posed varying hazards, particularly near coastal areas. Meteorologists indicated that warm sea surface temperatures contributed significantly to the creation and intensity of these storms, which are common from November to April in the Southern Hemisphere.

In late February 2025, both the South Pacific and Indian Oceans experienced an unusual cluster of tropical cyclones. A total of six storms were active, with five visible in a satellite image obtained by NOAA-20. This image utilized infrared signals to differentiate between the cooler cloud structures and the warmer ocean surface below. Prior to this observation, Tropical Cyclone Rae had been weakening after causing significant rainfall in Fiji.

Tropical Cyclones Alfred and Seru were located in the South Pacific. Cyclone Seru briefly reached Category 1 strength on the Saffir-Simpson scale while remaining offshore of Australia. Meanwhile, Cyclone Alfred was also predicted to remain distant from the coastline but was expected to generate hazardous coastal conditions in southern Queensland. On the day of observation, Alfred had reached Category 2 strength and was forecast to escalate to Category 4.

In the Indian Ocean, Tropical Cyclone Bianca was nearing the end of its journey after weakening to a tropical storm. It had previously attained Category 3 status but managed to stay away from land, thus avoiding impacts on Australia and nearby islands. In contrast, Cyclones Honde and Garance were posing a more immediate threat, particularly to Mauritius, which shut down its airport as Garance approached.

Meteorologists attributed the proliferation of tropical cyclones to elevated sea surface temperatures and minimal wind shear. A marine heat wave had persisted off Western Australia since September 2024, with anomalously high temperatures contributing to the cyclonic activity in late February. The Australian Bureau of Meteorology had predicted above-average instances of severe tropical cyclones this season, which typically spans from November to April in the Southern Hemisphere.

In summary, the late February 2025 activity of tropical cyclones in the South Pacific and Indian Oceans represents an unusual and concerning meteorological phenomenon. Factors such as elevated sea temperatures and weak wind shear conditions contributed to the development and intensification of several storms, including Cyclones Alfred, Seru, Bianca, Honde, and Garance. These developments underscore the ongoing risks related to tropical cyclone activity in these regions, especially as warm ocean temperatures persist.

Original Source: earthobservatory.nasa.gov