This twister landed in farmland near Young, and it’s not the first Australia has seen. Image: NSW Rural Fire Service/Facebook.
News of Aussie tornadoes makes national headlines, but just how rare are they?
On 11 September, residents near Young found themselves facing off against a tornado as a low-pressure system swept through much of the NSW southeast.
The twister was detected at Tubbul (northwest of Young) in the NSW Southwest Slopes region about 3:30 pm.
Speaking after the twister’s detection, Bureau of Meteorology senior meteorologist Angus Hines confirmed it was one of multiple tornadoes sighted in regional NSW.
It means the two at Tubbul and Caragabal (a village about 30 minutes from Grenfell) are Australia’s latest tornadoes to be added to the history books.
There were also unconfirmed reports of tornadoes in nearby areas, such as one near Cowra.
“Tornadoes are often too small to be seen on weather instruments like rain radars, but at least two tornadoes have been confirmed with video footage [from 11 September],” he said.
How hard it can be to detect tornadoes is something echoed by Australian National University Emeritus Professor Janette Lindesay.
She told Region the tornadoes were made unique simply because they were caught on camera, with many Australian twisters likely forming with no one the wiser. (They might be too small for weather satellites to pick up on, or they touch down in remote areas where no one sees them, for example.)
For them to form, weather conditions need to fall into a Goldilocks zone of wind and moisture.
The NSW tornadoes developed out of a low-pressure weather system that was sweeping across much of the state.
This shows that while tornadoes are most common in the US, which sees about 1000 every year, they can develop closer to home.
The BoM estimates that between 30 and 80 twisters form across Australia annually.
“They can’t occur anywhere, because they need quite specific conditions to happen,” Emeritus Professor Lindesay said.
“The only way to be certain is to see the actual tornado descending out of the cloud and there’s a record of it, or you see the damage.”
Emeritus Professor Janette Lindesay says tornadoes can “blast apart” trees and strip leaves from their branches. Photo: Edwina Mason.
Emeritus Professor Lindesay said the NSW tornadoes appeared to be typical twisters, with her colleagues not reporting any surprises.
The twisters were also on the smaller side (like many of Australia’s tornadoes tend to be).
“They appear to have been quite straightforward, as these weather systems go,” Emeritus Professor Lindesay said of them.
“The conditions under which they formed were typical … It wasn’t the most severe [tornado we’ve seen] at all.”
Residents of Tubbul and Caragabal were left with downed trees, roofs ripped off some sheds, and other damage to farmland.
Coastal communities, meanwhile, can see waterspouts – such as the one in 2012 at Batemans Bay – when a tornado passes over open water.
But Emeritus Professor Lindesay stressed that not every thunderstorm meant a tornado would develop, saying there needed to be wind shear (when there’s a difference in the air’s speed or direction).
“If you imagine a column of air [where] the bottom of it is being pushed in one direction and the middle or upper part is being impacted from a different direction … it can begin to twist and rotate,” she said.
“[Thunderstorm clouds] are the only clouds that are really big enough to generate these really big updrafts of air, the wind shear [going in] different directions, and an inflow of moisture to keep the whole thing going and energy being fed to the storm.
“That’s exactly what you need for tornadoes to form. … The conditions have to be just right.”
