An unusual line across the otherwise open landscape of Australia’s Nullarbor Plain might have gone unnoticed if not for a caver looking at satellite imagery.
uncertain
line → go → imagery
While browsing Google Earth, he came across a long, narrow disturbance cutting through the remote terrain.
asserted
he → browse → terrain
There were no buildings nearby, no obvious roads and no reports of a storm that could explain it.
uncertain
that → be → it
From above, the feature looked remarkably clear.
asserted
feature → look → ?
It stretched for about 11 kilometres, crossing the border between Western Australia and South Australia.
asserted
It → stretch → Australia
Months later, scientists examining the site and comparing older satellite images reached an explanation.
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scientists → examine → explanation
An Australian caver spotted the mysterious scar on Google Earth
Satellite images showed a scar between roughly 160 and 250 metres across, extending for kilometres through the dry landscape.
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spotted → spot → landscape
Its position also helped explain why the discovery took time.
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discovery → help → time
There is very little regular human activity across the surrounding country, meaning a weather event could pass through without anyone nearby to report it.
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event → be → it
The researcher used satellite imagery from different dates to establish when the change had appeared.
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change → use → dates
their comparison placed the formation of the scar between 16 and 18 November 2022.
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comparison → place → November
Around the same period, several circular blue areas could be seen in the imagery.
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areas → see → imagery
These were interpreted as temporary pools produced by heavy rainfall.
asserted
These → interpret → rainfall
Physical evidence linked the scar to a powerful storm
The scar itself was only part of the evidence.
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scar → link → evidence
Looking at images taken before and after the suspected event allowed the team to determine that the feature had not always been present.
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feature → look → event
Weather information from the same period pointed to a storm system moving across the region.
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information → point → region
The rainfall and cloud cover provided a plausible setting for the ground disturbance, but they did not by themselves establish that a tornado had passed over the Nullarbor.
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tornado → provide → Nullarbor
When researcher eventually examined the area, they found curved, cycloidal traces running along sections of the scar.
asserted
they → examine → scar
Such marks are associated with the movement of debris and vegetation within tornado damage paths.
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marks → associate → paths
Their presence gave the otherwise puzzling satellite feature a much more specific explanation.
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presence → give → explanation
What the unusual marks revealed
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revealed → reveal → What
The shape of the disturbance suggested that the storm had not simply produced widespread flooding or surface runoff.
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storm → suggest → flooding
Cycloidal marks were visible in parts of the affected area, while the scar showed erosion and the removal of soil and pieces of vegetation.
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scar → affect → vegetation
According to ABC News, Dr John Allen, a meteorologist at Central Michigan University who was not involved in the research, pointed, "Cycloidal marks are quite evident, and these are seen in US tornado damage paths.”
uncertain
these → accord → paths
"The appearance of the path without substantive evidence of flooding as an alternative cause would further lend support to this argument."
The study estimated that the tornado may have reached F2 to F3 intensity, with estimated wind speeds of more than 200 km/h.
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tornado → lend → km
Its track indicated movement from west to east, with clockwise rotation.
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track → indicate → rotation
The researcher estimated that it may have remained on the ground for between seven and 13 minutes.
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it → estimate → seven
Australia’s remote Nullarbor left the tornado unseen
The lack of eyewitness accounts is less surprising when the location is considered.
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location → leave → accounts
The Nullarbor Plain contains enormous areas of sparsely populated, largely flat terrain.
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Plain → contain → terrain
The tornado did not cross a town or strike major infrastructure, so there was little chance of someone seeing it directly or reporting damage immediately afterwards.
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someone → cross → damage
The researcher noted that only three tornadoes had previously been recorded in the region.
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tornadoes → note → region
All three occurred during November, the same month as the event identified from the satellite imagery.
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three → occur → imagery
That does not establish a broader seasonal pattern on its own, particularly in an area where observations are limited.
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observations → establish → area
It does, however, provide an interesting point of comparison for a region with relatively little historical tornado documentation.
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It → provide → documentation
The scar remained visible long after the storm
The dry conditions of the Nullarbor also helped preserve the evidence.
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conditions → remain → evidence
The disturbance could still be seen around 18 months after the suspected tornado.
uncertain
disturbance → see → tornado
In a landscape where vegetation recovery is slow, the damaged strip did not quickly disappear beneath new growth.
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strip → damage → growth
That persistence gave scientists an opportunity that would not necessarily exist in a wetter or more heavily vegetated environment.
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that → give → environment
A storm that had passed without witnesses had effectively left a record of its route on the ground.
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that → pass → ground
Matej Lipar, a physical geographer from the Slovenian Academy of Sciences and Arts and a study author, described the feature as a kind of surface signature left behind by the storm.
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Lipar → describe → storm
…and 1 more, not listed.
The Aporia
