Key Takeaways
- A freak weather event in Antarctica, known as a sudden stratospheric warming, is likely the cause of the hot, dry, and windy weather in eastern Australia
- The event, which occurred in September, caused temperatures in the stratosphere above the South Pole to rise by 50 degrees
- This phenomenon has been recorded only twice before, in 2002 and 2019, and was followed by some of Australia’s worst bushfire seasons
- Despite above-average rainfall in recent years, rainfall deficiencies have emerged in large pockets of the country, increasing the risk of bushfires
- The Australasian Fire and Emergency Service Authorities Council is warning of increased bushfire risk in parts of Victoria and central northern NSW
Introduction to the Unseasonal Weather
The forecast for a wet and cool spring in eastern Australia has given way to hot, dry, and windy weather, with a rising risk of bushfires. Climate scientists have identified a likely culprit for this unexpected turn of events: a freak weather event in Antarctica. The event, which occurred in September, caused temperatures in the stratosphere above the South Pole to rise by 50 degrees, a phenomenon known as a sudden stratospheric warming. This unusual event has been recorded only twice before, in 2002 and 2019, and on both occasions, it was followed by some of Australia’s worst bushfire seasons.
The Impact of Sudden Stratospheric Warming
The sudden stratospheric warming event in September has had a significant impact on the weather in eastern Australia. The heat spike caused the polar vortex to weaken, leading to a shift in the strong westerlies that form a tight circle around Antarctica from autumn until the start of summer. This, in turn, has led to a hot, dry, and windy spring, with heatwaves in south-eastern Australia and early season bushfires in NSW. The dry conditions have exacerbated the risk of bushfires, and the Australasian Fire and Emergency Service Authorities Council is warning of increased bushfire risk in parts of Victoria and central northern NSW.
Bushfire Risk and Rainfall Deficiencies
Despite two years of above-average rainfall, which has increased soil moisture levels and reduced the chance of high-risk fire days, rainfall deficiencies have emerged in large pockets of the country. This has increased the risk of bushfires, particularly in areas with high fuel loads, such as central northern NSW. The Australasian Fire and Emergency Service Authorities Council is warning of increased bushfire risk in these areas, and the community is being urged to be vigilant and prepared for the upcoming bushfire season. While there are currently no warnings for widespread heightened bushfire risk in eastern Australia, the dry spring could exacerbate risks this summer.
The Science Behind Sudden Stratospheric Warming
Sudden stratospheric warming events are rare and complex phenomena that are not yet fully understood. They occur when there is a sudden increase in temperature in the stratosphere, usually above the polar regions. This can cause the polar vortex to weaken, leading to a shift in the jet stream and changes in the weather patterns. In the case of the September event, the temperature increase was particularly significant, rising by 50 degrees in a matter of days. This has had a profound impact on the weather in eastern Australia, and climate scientists are working to understand the mechanisms behind this event and its implications for future weather patterns.
Conclusion and Future Implications
The freak weather event in Antarctica has had a significant impact on the weather in eastern Australia, leading to hot, dry, and windy conditions and an increased risk of bushfires. While the causes of this event are complex and not yet fully understood, climate scientists are working to understand the mechanisms behind it and its implications for future weather patterns. As the bushfire season approaches, it is essential that communities are prepared and vigilant, and that measures are taken to mitigate the risk of bushfires. The Australasian Fire and Emergency Service Authorities Council is warning of increased bushfire risk in parts of Victoria and central northern NSW, and it is crucial that the community takes heed of these warnings and takes steps to prepare for the upcoming bushfire season.
