A speleologist looking at satellite images of the Nullarbor Plain earlier this year came across something unexpected: a massive, mysterious scar cutting across the barren landscape. We have attracted the attention of scientists, including my colleagues and I. Upon further investigation, we realized that the scar was created by a violent hurricane that no one knew about. We report the results of a new study published today.

Hurricanes are a known threat in the United States and other countries. But they also happen in Australia. Without the power of technology, this wonderful example of nature’s cruelty might have gone unnoticed. It is important to study the effects of hurricanes to help us anticipate and prepare for the next big change.

History of cyclones in Australia

Hurricanes are rotating columns of air that fall to the ground from a storm, often causing wind speeds in excess of 200 kilometers per hour. They can cause massive destruction, such as uprooting trees, collapsing buildings, and scattering debris over long distances.

Hurricanes have been recorded on all continents except Antarctica. Most often they occur in the Great Plains region of the United States and in the northeast of India – in Bangladesh. The first tornado observed in Australia occurred in the suburbs of Sydney in 1795. But hurricanes were not scientifically confirmed here until the late 1800s.

Documented cases in Australia in recent years include a cyclone that passed through northeast Victoria in 2013 and reached the New South Wales border. It brought winds of 250-300 kilometers per hour, damaging settlements along the Murray River.

And in 2016, a severe storm caused at least seven tornadoes to form in central and eastern South Australia. It is important for scientists to accurately predict hurricanes so we can warn communities. That’s why it was useful to study the Nullarbor Tornado Scar.

vortex secret

The Nullarbor Plain is a remote, dry, treeless land in South Australia. The man who discovered the scar used Google Earth satellite images to look for caves or other karst features in Nallabor.

Karst is a limestone-covered landscape with distinctive landforms. The discovery of the scar came to the attention of my colleagues and me through a collaborative network of researchers and researchers studying the Nullarbor karst. The scar extends from Western Australia across the border into 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 from several years ago to determine that the tornado occurred between November 16 and 18, 2022. Blue circular patterns appeared near the scar, indicating puddles associated with heavy rain. My colleagues and I then traveled to the site in May of this year to examine and photograph the scar and the surrounding landscape.

Our results were published in the Journal of Southern Hemisphere Earth Systems Science.

What did we find?

The scar is 11 kilometers long and 160 to 250 meters wide. It has striking patterns called “cycloid signatures” formed by hurricane vortices. This indicates that the hurricane was no ordinary storm but a severe F2 or F3 storm spinning with damaging winds of more than 200 kilometers per hour.

The tornado probably lasted seven to 13 minutes. Characteristics of the scar indicate that the swirling wind in the hurricane moved clockwise. We also believe the hurricane moved from west to east, which is consistent with the direction of the strong cold front in the region at that time.

Local weather observations also recorded heavy cloudiness and rainfall during this period in November 2022.

Unlike tornadoes that hit populated areas, this tornado did not damage homes or towns. But it still left its mark, eroding soil and vegetation and altering the Earth’s surface. Remarkably, 18 months after the incident, the scar was still clearly visible both on satellite images and on the ground. This is probably because vegetation grows slowly on this dry land and therefore erosion has not yet taken effect.

Predict and prepare

This fascinating discovery in the Nullarbor Plain shows how powerful and unpredictable nature can be; sometimes without us even realizing it. Only three tornadoes had previously been documented in the Nullarbor Plain. This is likely because the area is remote, there are few eyewitnesses, and the events did not cause damage to property and infrastructure. Interestingly, all three of these hurricanes also occurred in November.

Our research provides valuable information about hurricanes in this remote and understudied region. This helps us understand when and under what conditions such hurricanes occur.

It also highlights the importance of satellite imagery in identifying and analyzing weather events in remote locations and helping us predict and prepare for the next big event. Finally, the results are a stark reminder that extreme weather can happen anywhere at any time.