Tropical Cyclone Alfred is currently bearing down on Queensland, marking a significant meteorological event for the region. As the first cyclone in 51 years to approach the Australian east coast near Brisbane, its arrival has sparked discussions about its origins. The potential impacts and connections to climate change are also being discussed. As our CEO, Roshan, faces the cyclone head-on from his home on the Gold Coast, we’ll look at what makes up a cyclone and what this means for our climate.
Formation and characteristics of Cyclone Alfred
Cyclones, also known as hurricanes or typhoons in other parts of the world, are intense circular storms that originate over warm tropical oceans. They are characterised by low atmospheric pressure, high winds, and heavy rain. The formation of a cyclone requires specific conditions: warm sea surface temperatures (typically above 26.5°C), atmospheric instability, and high humidity in the lower to middle levels of the troposphere. Additionally, a pre-existing weather disturbance is needed. Finally, the Coriolis effect, resulting from Earth’s rotation, imparts the characteristic spin to these storms.
Cyclone Alfred developed over the warm waters of the Coral Sea. Sea surface temperatures were conducive to cyclogenesis. The presence of a pre-existing low-pressure system, combined with favourable atmospheric conditions, allowed the storm to intensify into a Category 2 cyclone. As of the latest reports, Alfred is expected to make landfall between Brisbane and the Gold Coast around midnight on Thursday. This coincides with a high tide.
Expected impacts on Queensland and New South Wales
The impending landfall of Cyclone Alfred poses several threats to both Queensland and northern New South Wales:
- Storm surges: Coastal areas are at risk of storm surges up to 1 metre above usual tide levels, potentially inundating low-lying regions.
- Heavy rainfall: Forecasts predict rainfall totals up to 800mm, leading to life-threatening flash floods. Brisbane alone could see up to 20,000 homes affected by flooding.
- Strong winds: Winds could reach speeds of up to 130 km/h, causing structural damage, uprooting trees, and leading to widespread power outages.
- Disruptions to services: Authorities have announced closures of schools, suspension of public transport, and cancellation of elective surgeries in anticipation of the cyclone’s impact. Evacuation centres have been established, and residents in high-risk areas are urged to evacuate promptly.
Cyclone Alfred and climate change: Is there a connection?
The occurrence of Cyclone Alfred near Brisbane, a region that hasn’t experienced such an occurrence since Cyclone Zoe in 1974, raises questions about the influence of climate change on cyclone activity.
Climate change has been linked to alterations in the behaviour of tropical cyclones:
- Frequency and intensity: While the overall frequency of cyclones globally hasn’t shown a significant increase, there is evidence suggesting a rise in the number of intense cyclones (Categories 4 and 5). Warmer sea surface temperatures provide more energy, potentially leading to more powerful storms.
- Geographical shifts: Some studies indicate that cyclones are occurring at higher latitudes than previously recorded. This is possibly due to changes in atmospheric circulation patterns driven by global warming.
- Rainfall rates: A warmer atmosphere holds more moisture, leading to increased rainfall during cyclonic events. This exacerbates the risk of flooding, even in regions not traditionally prone to such high precipitation levels.
However, attributing a single event like Cyclone Alfred directly to climate change is challenging. Cyclones are complex phenomena influenced by various factors, including natural climatic variability. Nonetheless, the unusual nature of Alfred’s path and intensity aligns with broader trends observed in a warming climate.
Preparation and response
Given the potential severity of Cyclone Alfred, authorities have implemented several measures to safeguard communities:
- Evacuations: Residents in coastal areas susceptible to storm surges have been advised to evacuate. Evacuation centres have been established to accommodate those displaced.
- Resource allocation: The government has pre-deployed resources, including generators, health staff, and additional police officers, to affected areas, especially islands. Sandbagging stations have been set up to mitigate flooding.
- Public advisories: Continuous updates are being provided through various media channels, urging residents to secure their properties, prepare emergency kits, and stay informed about the cyclone’s progress.
Queensland residents are encouraged to stay alert and informed.
Conclusion
Cyclone Alfred’s approach serves as a stark reminder of the dynamic and potentially destructive nature of tropical cyclones. Its occurrence near Brisbane after more than five decades is noteworthy. It underscores the importance of preparedness and resilience in the face of natural disasters. Whether directly linked to climate change or not, events like Alfred highlight the need for adaptive strategies. These strategies aim to protect communities and infrastructure in an evolving climatic landscape.
