In late 2019, the sky over Australia turned red with smoke. The fires burned so intensely that the heat lifted air to the altitude where airplanes fly — into the stratosphere. There, tens of kilometers up, the smoke didn't just disperse. It swirled into a massive air vortex, like a giant funnel. Scientists named this vortex Kubor, after the sky spirit from Australian Aboriginal mythology.

Such vortices had been seen before in satellite images, but no one could say exactly where the vortex ended and ordinary air began. The authors of the new study used a method similar to finding the boundary between water and oil in a glass. They tracked how tiny 'parcels' of air moved and found lines that don't break or mix with the surrounding space. It turned out that Kubor has a clear boundary that holds for up to 40 consecutive days. The entire vortex lives for almost 60 days, changing its shape like a dancer who rearranges their pose but never leaves the stage. Moreover, the vortex appeared at different altitudes at different times: it formed earlier at lower levels and later at higher ones, where it also dissipated faster.

Why does this matter? Smoke from such fires can affect climate for years: soot particles absorb sunlight and heat the stratosphere, while chemicals destroy the ozone layer. Understanding how long smoke remains in a compact vortex helps predict these effects more accurately. Now scientists have a tool to find and track similar vortices during future catastrophic fires.