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 discovery intrigued scientists, including my colleagues and me. Upon further investigation, we realized that the scar was caused by a ferocious tornado that no one knew had occurred. We outline the findings in new research published today.
Tornadoes are a well-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 cruelty would have gone unnoticed. It is important to study the aftermath of the tornado to help us predict and prepare for the next big twister.
Australia’s tornado history
Tornadoes are violent, rotating columns of air that fall to the ground from thunderstorms, creating winds often exceeding 120 miles per hour. They can cause enormous destruction: uprooting trees, tearing apart buildings and throwing debris over great distances.
Tornadoes have been reported on every continent except Antarctica. They are most common 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 closer examination, scientists realized that the scar was created by a ferocious tornado
The scar extends from Western Australia across the border to South Australia
The earliest recorded tornado in Australia occurred in 1795 in the suburbs of Sydney. But a tornado was not scientifically confirmed here until the late 19th century.
In recent decades, documented examples in Australia include a 2013 tornado that crossed northeastern Victoria and moved toward 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 severe storm spawned at least seven tornadoes in central and eastern parts of South Australia.
It’s important that scientists can accurately predict tornadoes so we can warn communities. That’s why the Nullarbor tornado scar was useful to study.
A swirling mystery
The Nullarbor Plain is a remote, dry, treeless stretch of land in southern Australia. The man who discovered the scar had used Google Earth satellite images to search the Nullabor for caves or other karst features.
Karst is a landscape with limestone and distinctive landforms. The discovery of the scar came to the attention of my colleagues and me through the collaborative network of researchers and explorers who study the Nullarbor karst.
The scar extends from Western Australia across the border to South Australia. 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 along the scar, indicating pools of water associated with heavy rainfall.
Tornadoes are a known threat in the United States, but also occur in Australia.
My colleagues and I then traveled to the site in May this year to survey and photograph the scar and the adjacent landscape.
Our results were 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 exhibits distinctive patterns called “cycloidal markings,” formed by tornado suction vortices. This suggests that the tornado was not an ordinary storm, but was in the strong F2 or F3 category, with destructive winds of more than 200 kilometers per hour.
The tornado probably lasted between seven and thirteen minutes. Features of the scar suggest that the swirling winds in 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 that time.
Local weather observations also recorded intense cloud cover and rainfall during that period in November 2022.
Unlike tornadoes that hit populated areas, this one caused no damage to homes or towns. But it has nevertheless left its mark, eroding soils and vegetation and reshaping the Earth’s surface.
Remarkably, 18 months after the event, the scar was still clearly visible, both in satellite images and on the ground. This is probably because the vegetation grows slowly in this dry landscape, so the erosion has not yet been covered.
Tornadoes have been reported on every continent except Antarctica
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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 previously been documented on the Nullarbor Plain. This is likely because the area is remote and there are few eyewitnesses, and because the events do not cause damage to property or infrastructure. Interestingly enough, these three tornadoes happened in November, just like this one.
Our research provides valuable insights into tornadoes in this remote and understudied region. It helps us understand when and under what conditions these types of tornadoes occur.
It also highlights the importance of satellite imagery in identifying and analyzing weather phenomena in remote locations, and in helping predict and prepare for the next big event.
And finally, the results are a clear reminder that extreme weather can strike anywhere, anytime.