Unveiling the Threat: Why Deadly Cyclones Are Moving Closer to Sydney

On Tuesday morning, Cyclone Alfred was about 500 kilometers east of Brisbane. It was classified as a category 2 storm. The Bureau of Meteorology predicts it will move south and then turn sharply west, making landfall north of Brisbane between late Thursday and Friday.

The most severe impacts are expected in areas south of the cyclone, particularly Brisbane, the Gold Coast, and the Northern Rivers. These regions could experience strong winds, heavy rainfall, and high coastal swells.

If Cyclone Alfred were to change direction, it might even reach as far south as Sydney. Scientists noted that sea surface temperatures are unusually warm enough to support cyclones near Sydney right now.

According to Mortlock, a cyclone typically forms when ocean temperatures reach around 26-27 degrees Celsius. However, if the water cools down, the storm’s strength diminishes. Australia’s coastline is currently experiencing a marine heatwave, which can help sustain a cyclone’s strength.

Ritchie commented that if Alfred were to track south and avoid making landfall near Brisbane, it could maintain its intensity due to the warm water as it approached Sydney. But that’s unlikely this time.

A tropical cyclone is a powerful storm that forms over warm ocean waters. It draws energy from the heat of the sea and can cause considerable damage when it strikes land. These storms are similar to hurricanes and typhoons but rotate in different directions, depending on their hemisphere.

If Alfred makes landfall, it would be the first tropical cyclone to affect New South Wales since Nancy in 1990. Typically, cyclones lose strength before reaching southern Queensland or northern NSW. Nonetheless, those that do arrive can create widespread issues.

Interestingly, there has been a decline in the number of cyclones hitting the Australian east coast over the last few decades, despite a global increase in cyclone activity. However, the cyclones that do form are expected to be more intense. Ritchie pointed out that as the atmosphere warms, it can hold more moisture, leading to heavier rainfall and longer-lasting storms.

Recent events, like Cyclone Jasper in December 2023, show that flooding risks from these storms are growing. Increased rainfall is becoming a significant factor when assessing the severity of these weather events.