Australian bushfires developing their own weather systems
The bushfires ravaging Australia are generating so much heat that they are creating their own weather systems including dry lighting storms and fire tornadoes.
Yesterday, the New South Wales Rural Fire Service (RFS) warned that a fire on the coast was generating its own weather system 287 km (178 miles) south of Sydney.
“A fire-generated thunderstorm has formed over the Currowan fire on the northern edge of the fire near Nowra. This is a very dangerous situation. Monitor the conditions around you and take appropriate action,” the RFS said on social media.
The weather conditions are the results of the formation of pyrocumulonimbus clouds. They have been recorded all over the world but as the global climate changes, they may become a more frequent occurrence for Australians, the country’s Climate Council said in a 2019 report.
A RFS firefighter was killed on Monday by a fire tornado caused by the collapse of a pyrocumulonimbus cloud formation that rolled over the fire truck he was in.
The pyrocumulonimbus clouds are essentially a thunderstorm that forms from the smoke plume of a fire as intense heat from the fire causes air to rise rapidly, drawing in cooler air, according to information from the Australian Bureau of Meteorology.
As the cloud climbs and then cools in the low temperatures of the upper atmosphere, the collisions of ice particles in the higher parts of the cloud build up an electrical charge, which can be released as lightning.
These can cause dangerous and unpredictable changes in fire behaviour, making them harder to fight as well as causing lightning strikes that could ignite new fires.
Half a billion animals killed!
There is a widely-reported estimate that almost half a billion (480 million) animals have been killed by the bush fires in Australia. It’s a figure that came from Prof Chris Dickman, an expert on Australian biodiversity at the University of Sydney. On Friday, he released a statement explaining how he had reached the figure - a statement which refers to the number of animals affected rather than those necessarily dying as a direct result of the fire. The numbers are based on a report he co-wrote in 2007 for the World Wide Fund for Nature (WWF) on the impact of land-clearing on Australian wildlife in New South Wales. It estimated that there were an average of 17.5 mammals, 20.7 birds and 129.5 reptiles per hectare. They’ve then multiplied that by the amount of land hit by the fires. The estimation of 480 million mammals, birds and reptiles came out of it. But he said large mammals are expected to be move away from fire and the less mobile species really in the firing line.