Earlier this year, a caver was studying satellite images of the Nullarbor Plain when he came across something unexpected: a huge, mysterious scar etched into the arid landscape.
The finding intrigued scientists, including my colleagues and me. Upon further investigation, we realized that the scar was created by a fierce tornado that no one knew had occurred. We describe the findings in new research published today.
Tornadoes are a known threat in the United States and elsewhere. But they also happen in Australia.
Without the power of technology, this remarkable example of nature’s ferocity would have gone unnoticed. It is important to study tornado aftermath to help us predict and prepare for the next big tornado.
The history of tornadoes in Australia
Tornadoes are violent, rotating columns of air that fall from storms to the ground, causing winds that often exceed 200 kilometers per hour. They can cause massive destruction: uprooting trees, smashing buildings, and throwing debris great distances.
Tornadoes have been recorded on every continent except Antarctica. They occur most frequently in the Great Plains region of the United States and in the northeastern India-Bangladesh region.
The man who discovered the scar had used satellite images from Google Earth.
Upon further investigation, scientists realized that the scar was created by a fierce tornado.
The scar stretches from Western Australia all the way to the border into South Australia.
The oldest tornado observed in Australia occurred in 1795 in the suburbs of Sydney. But the existence of a tornado was not scientifically confirmed here until the end of the 19th century.
In recent decades, documented cases in Australia include a 2013 tornado that crossed northeast Victoria and traveled to the New South Wales border. It brought winds of between 250 and 300 kilometers per hour and damaged Murray River townships.
And in 2016, a strong storm produced at least seven tornadoes in the central and eastern parts of South Australia.
It is important for scientists to accurately predict tornadoes so they can issue warnings to communities. That’s why it was useful to study the Nullarbor tornado scar.
A dizzying mystery
The Nullarbor Plain is a remote, dry, treeless stretch of land in southern Australia. The man who discovered the scar had been using Google Earth satellite images to search for caves or other karst features in Nullabor.
Karst is a landscape underlain by limestone that features distinctive geographical features. The discovery of the scar came to the attention of my colleagues and me across the collaborative network of researchers and explorers studying the Nullarbor karst.
The scar stretches from Western Australia to the South Australian border. It is located 20 kilometers north of the Trans-Australian Railway and 90 kilometers east-northeast of Forrest, a former railway settlement.
We compared satellite images of the site over several years to determine that the tornado occurred between November 16 and 18, 2022. Blue circular patterns appeared next to the scar, indicating pools of water associated with heavy rain.
Tornadoes are a known threat in the United States, but they also occur in Australia.
My colleagues and I then traveled to the site in May this year to examine and photograph the scar and the neighboring landscape.
Our results have been published today in the Journal of Southern Hemisphere Earth Systems Science.
what we found
The scar is 11 kilometers long and between 160 and 250 meters wide. It features striking patterns called “cycloidal marks,” formed by tornado suction vortices. This suggests that the tornado was not an ordinary storm, but a strong F2 or F3 category, spinning with destructive winds of more than 200 kilometers per hour.
The tornado probably lasted between seven and 13 minutes. The characteristics of the scar suggest that the swirling wind within the tornado moved clockwise. We also believe the tornado moved from west to east, which is consistent with the direction of a strong cold front in the region at the time.
Local weather observations also recorded heavy cloudiness and precipitation during that period in November 2022.
Unlike the tornadoes that hit populated areas, this one did not damage homes or towns. But it still left its mark, eroding soil and vegetation and reshaping the Earth’s surface.
Remarkably, the scar was still clearly visible 18 months after the event, in both satellite and ground images. This is probably because vegetation grows slowly in this dry landscape, so it had not yet covered erosion.
Tornadoes have been reported on every continent except Antarctica.
Predict and prepare
This fascinating discovery on the Nullarbor Plain shows how powerful and unpredictable nature can be, sometimes without us knowing it.
Only three tornadoes have been documented on the Nullarbor Plain so far. This is probably because the area is remote, with few eyewitnesses, and the events do not damage property or infrastructure. Interestingly, those three tornadoes occurred in November, as did this one.
Our research provides valuable information about tornadoes in this remote and understudied region. It helps us understand when and under what conditions these types of tornadoes occur.
It also emphasizes the importance of satellite images in identifying and analyzing weather phenomena in remote locations and in helping us predict and prepare for the next big event.
And finally, the results are a stark reminder that extreme weather can occur anywhere and at any time.