Tornados on Mars

Ancient cosmic impacts on Mars may have created powerful wind vortices similar to sideways tornadoes and those whirling winds would have rolled across the Red Planet's surface, a new study finds[1].

Peter Schultz and Stephanie Quintana, analyzed infrared images taken during nighttime on Mars by NASA's Mars Odyssey orbiter. Areas that appeared brighter at night were surfaces that retained more heat from the previous day than surrounding regions, 'just as grassy fields give off heat more quickly than rock,' Schultz explained.
The images revealed sets of bright streaks emanating from a few big impact craters on Mars. This infrared brightness was likely due to exposed blocky rock surfaces, 'which retain more heat than surfaces covered by dust,' Schultz said in a statement. 'That tells us that something came along and scoured those surfaces bare.'

These streaks can extend quite far from the impacts that created them. For instance, on the 20 km Santa Fe crater in the flat lowland region in Mars' northern hemisphere known as Chryse Planitia, the streaks can extend more than 120 km away from the point of impact.
At times, debris kicked up by the impacts that created these streaks appears to have fallen on top of the streaks themselves. This finding suggests that the streaks were produced before the debris landed and that they were created very rapidly after the impacts, likely by winds. The researchers determined that tornado-like wind vortices might explain the streaks.

When an asteroid, comet or other body strikes a planet at high speed, tons of material from both the impactor and the surface it hits gets vaporized instantly. This vapor travels outward at very high speeds from the impact point and interacts with the atmosphere to create very strong vortices. These winds can exceed 1000 km/h.
BTW: An ancient Martian crater may have once been filled with water. The European Space Agency's Mars Express orbiter created a composite image of the scene, which is located in the Margaritifer Terra region of the planet's southern hemisphere. So-called 'chaotic terrain' seen in and around the 70 km wide crater suggests that there could have been a lake or large amounts of subsurface water in the region around 4 billion years ago.

[1] Schultz, Quintana: Impact-generated winds on Mars in Icarus – 2017

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