A remote cattle station in the Northern Territory is experiencing an unusual problem with its stock yards.
The ground is on fire and it is proving very difficult to put out.
Terry Martin from Mt Denison Station said after weeks of extraordinarily hot temperatures, smoke started to rise from the yards and he cannot work out why.
“We saw the smoke and went to have a look and there’s this burnt ring on the ground and it’s smouldering around the edges,” he said.
“We let it be to see what would happen, and since then there’s now another 10 or so spots that have started up and they’re slowly spreading.”
Melting the thermometer
Mr Martin said the family melted a thermometer while trying to work out how hot the soil was.
“We tried digging [some of] this up with a shovel, but the ground is too hard, it’s just baked hard,” he said.
“We stuck a candy-thermometer in — we could only dig down about 2 inches and it read about 200 degrees Celsius within 30 seconds, and then it just melted the glass.”
He said he called a geologist and also rang Bushfires NT to ask if anyone knew what was going on, or if they had seen anything like this before.
“Hopefully someone can get back to us with some information about what’s happening out here,” he said.
So what is causing the fire?
Spontaneous combustion is the likely reason for the smouldering ground at Mt Denison, according to David Bowman, a professor of pyrogeography and fire science at the University of Tasmania.
Professor Bowman said spontaneous combustion was mostly associated with hay bales, and that the event at Mt Denison was like nothing he had ever seen before.
“From the video that I saw, there’s a surface fire burning in a stockyard, and what I think that tells us is that there is a lot of cattle, there is a lot of excrement, which is very rich in organic matter, it’s very combustible material,” he said.
“This is a unique example of enriched organic matter in the desert because of the high concentration of animals, being pulverized by their hooves, heated up by a heatwave, moistened by a lot of urine, plus bacteria, and then the wind came and triggered a little ground fire — very interesting.”
Professor Bowman said a changing climate was creating unusual fire events across the world.
“We are seeing more and more unusual expressions of fire in the landscape,” he said.
“Here in Tasmania, we’ve seen incredible dry lightning storms igniting dried-out vegetation, in Victoria an old disused lake bed used for dairy farming catching on fire, in Tasmania drained swamps catching on fire.
Professor Bowman had advice for the owners of Mt Denison Station.
“They need to dig into the ground, and just confirm that it is a surface fire,” he said.
“And then if they want to put it out, they just scrape around it, scrape back the mineral soil and it will burn itself out.”