Severe Tropical Cyclone Zelia is approaching Port Hedland in Western Australia, having intensified from a Category 3 storm to nearly a Category 5 in just 24 hours. The cyclone’s rapid intensification is expected to make landfall sometime on Friday.
According to Hamish Ramsay, a cyclone expert and Senior Research Scientist at CSIRO, the event is notable for its intense strengthening. “This is a pretty impressive intensification event,” he says. Cyclones are classified into five categories based on wind speed, ranging from less than 125km/h to over 280km/h.
Ramsay notes that intensification events have become increasingly common over the past 40 years, and climate change is likely playing a significant role in these events due to rising sea surface temperatures. He cites examples of rapid intensification events such as Hurricanes Milton and Helene, which formed in the Gulf of Mexico before hitting Florida.
Cyclones form when warm tropical ocean water heats the air above, causing it to rise. The storm’s rotation is influenced by the Earth’s spin and atmospheric winds from a specific direction. Cyclones that stall can lead to prolonged periods of heavy rainfall, as seen with Cyclone Jasper in 2023, which caused unprecedented flooding in Australia.
Ramsay warns that climate change will lead to a wetter and more intense future for the Tropics, with increased moisture and stronger storms resulting in more rainfall. The probability of heavy rain near Cairns has already increased by 50% since 2000 and is expected to double by the end of this century.
The rapid intensification of cyclones makes it difficult to predict, which can catch people off guard, leading to more damage, injuries, and deaths. Rising sea levels also pose a significant risk. The need for better forecasts and faster ways to prepare are crucial in mitigating the impact of these events.
Source: https://cosmosmagazine.com/australia/what-makes-a-cyclone-accelerate