A handful of separate wildfires raging west of Sydney, Australia, have already ravaged 300,000 acres of land and destroyed 200 houses. As they continue to burn, officials are warning that some of the blazes could merge into one "mega-fire" and then spark a freaky phenomenon known as a "fire cloud." And in some instances, they're warning that such clouds can actually catalyze tornados.
Already, the Blue Mountains region — where the worst of the fires are roaring — has seen something of a perfect storm of weather conditions for brushfires. Unusually warm temperatures prior to fire season, combined with low precipitation, parched miles of foliage and made them more likely to catch fire. In recent weeks, hot weather and high winds have made fighting back the fires a particularly daunting challenge.
"The fire behavior goes really extreme."
And things could get even worse. In what officials are describing as "a worst-case scenario," two of the fires threaten to link up and form one "mega-fire" that would yield enough energy to catalyze unusual and unpredictable weather conditions. Among them is a pyrocumulus — basically an enormous, high-altitude thundercloud. "... A fire is producing so much energy it punches up through the troposphere a huge plume of smoke, essentially creating a thunderstorm with lots and lots of energy in it," Owen Price, a researcher at the University of Wollongong, told reporters. "Then it starts to suck in air from all around, so there's more oxygen and it feeds back on itself so the fire behavior goes really extreme."
Yes, a tornado comprised of flame
Sometimes, these pyrocumulus clouds can actually yield rain showers that help to subdue flames. In other instances, however, they simply generate lightning — which can, in turn, trigger new fires when striking the ground. And as the clouds suck up air, they can also catalyze a process called pyro-tornadogenesis, first documented during a 2003 Australian wildfire. An ensuing "fire tornado" (yes, a tornado comprised of flame) has the potential to be extremely destructive. "A fire tornado, like a true tornado, is attached to the underside of a thunderstorm," said Rick McRae, who analyzed 2003 data to report on the event. "It had major effects on the behavior of the fire on the urban edge and had enough force to remove roofs from houses and to blow cars off the road."
For now, hundreds of firefighters are doing their best to control the raging fires, as officials continue to monitor weather conditions. Unfortunately, Australia's notoriously destructive fires could become even more severe in the future: earlier this week, the head of a UN committee on climate change warned that global warming is "absolutely" linked to wildfires.