Understanding Australia’s Cyclone Season: A Look at Recent Events and Preparedness
This article reviews Australia’s busy cyclone season, highlighting significant storms like Severe Tropical Cyclone Sean and Tropical Cyclone Alfred, and explains how cyclones form and are classified. It emphasizes the importance of preparedness for communities at risk and offers insights into the meteorological processes behind these severe weather events.
Cyclones have dominated headlines this season, marking one of the busier years in recent memory. The severity of weather events has consistently surprised communities from the Pilbara coast, where Severe Tropical Cyclone Sean unleashed record rainfall in January, to the near-miss with Severe Tropical Cyclone Zelia over northern WA in February. It did not end there; Tropical Cyclone Alfred wreaked havoc in Queensland and New South Wales come March, and we even saw Ex-Tropical Cyclone Errol, a Category 4 system while at sea, cause disruption in the Kimberley as a tropical low in April.
Typically, Australia averages about 11 tropical cyclones annually, with expectations of around four making landfall each season. The season runs from November through April, predominantly affecting areas north of Exmouth on the WA coast, across the Top End, and areas north of Brisbane on the east coast. Although they generally stay in these warmer zones, cyclones have been known to push further south, presenting risks to a wider range of communities.
In the southern hemisphere, cyclones rotate clockwise. For those in the northern hemisphere, these rotating storms are either called typhoons or hurricanes and spin in the opposite direction. The conditions necessary for cyclones are notably specific; water temperature must sit at a minimum of 26.5 °C. This is why they primarily form in tropical regions. The process begins with evaporation drawing moisture upward, and if air pressure decreases, the clouds begin to spin.
Continual humidity plays a crucial role in maintaining this system as it generates energy critical for the cyclone’s development and speed. For a storm to officially be classified as a cyclone, winds must reach speeds of at least 119km/h. At the cyclone’s center lies what is known as the eye, which measures roughly 40 kilometers in width, marked by low winds and clear skies due to the downward movement of cooler air.
Cyclones can generate substantial swells and surges, posing significant threats to coastal areas and marine vessels. However, once these storms make landfall or encounter cooler waters, they often lose energy and strength. Most cyclones have a lifecycle of about a week.
In summary, this cyclone season has been noteworthy, with several severe storms affecting various regions of Australia since January. Cyclones, requiring very particular conditions, usually form in tropical areas, can vary significantly in strength, and are named through a specific system of rotating lists. Understanding cyclones and preparing for them is vital for communities in affected areas, as storms have the potential to cause serious damage, especially when fed by warm ocean waters.
Original Source: particle.scitech.org.au
