Australia's summer is always something to look forward to, but particularly high hopes were pinned to this year’s sunny season. After months of uncertainty, social restrictions and limited travel, the promise of blue skies, soaring temps and open borders seemed a well-deserved reward. However, instead of catching rays, a surprise Christmas surge has left Sydneysiders and Melburnians in fear of catching the virus, and to add insult to injury, the entire Eastern Seaboard of Australia has experienced some of the most dismally damp December and January weather in a decade.
So, why has the summer deserted us in our hour of need? You may well have heard the words ‘La Niña’ and a shrug offered by way of explanation, but it’s worth diving deeper to understand just how significant this global weather event truly is – and how long we can expect it to last.
Australia’s Bureau of Meteorology officially declared the start of a major La Niña event in September – the first time Down Under since late 2010. It occurs when one of the main climatic drivers in the Southern Hemisphere, the El Niño Southern Oscillation, enters a cooling phase. After almost four years of remaining largely stable – or ‘neutral’ to use the official terminology – this current of air has shifted, sucking cooler waters from the Pacific up into high-altitude winds while pushing warmer waters from the equator towards the Australian coast, which in turn allows even more moisture to enter Australia’s weather systems. The result, unsurprisingly, is more rain, as this huge volume of water vapour condenses above Australia. Meanwhile, the accompanying cloud cover reflects much of the summer sunlight, resulting in far lower temperatures, and even when the mercury does manage to climb, the conditions are far muggier at ground level.
Short periods of La Niña weather occur throughout the world with relative regularity; the last time Australia had a taste of this big wet was back in 2017. However, this year’s La Niña is predicted to be the largest since 2010, which was the cause of the devastating Queensland floods of early 2011 and lasted until mid-2012 – yes, that’s right, we could be in for another rubbish summer next year too.
In fact, there’s an eerie symmetry shared between the current rains and the strongest La Niña on Australian records. Starting in June of 1916 and ending in early 1918, just as the worldwide Spanish Flu outbreak arrived on our shores, it seems Australians have had to contend with the double whammy of epic rainfall and a global health emergency before.
But it’s not all bad news. Australia has been in drought for several years, which has not only been impactful for rural communities and farmers, but it was also a major driver behind the devastating bushfires that raged across the country in late 2019 and early 2020. Indeed, at the time of the bushfire disaster, meteorologists unanimously agreed that sustained rainfall, in the volumes we’ve experienced this year, would be the only means of halting the blazes that relentless incinerated millions of hectares of the country for almost three months. Thanks to the sustained downpours that ushered in an uncharacteristically sodden new year, reservoirs are refilling and the tinder-dry bush is getting a well-earned drink. So, while we could be in for many more months – or even years – of more rain than shine, La Niña's many dark clouds do have a silver lining.