Dust storms on Mars

If you've seen the movie 'The Martian', starring Matt Damon, you might have guessed that the weather on Mars can be pretty unpredictable.

When a huge dust storm on Mars turns up the power, it can easily turn into a gigantic weather phenomenon. During the last Martian global dust storm in 2018 orbiting space crafts kept a close eye on the planet, getting a good look at the storm's life-cycle. The tower that rose during that storm rose as high as 70 to 90 kilometers[1].

"Global dust storms are really unusual," said David Kass, a co-author of the paper. "We really don't have anything like this on the Earth. On Mars, the entire planet's weather changes for several months."

During the 2018 storm, NASA's Mars Reconnaissance Orbiter (MRO) saw something unusual. "Normally the dust would fall down in a day or so," said Heavens. "But during a global storm, dust towers are renewed continuously for weeks." In some cases, multiple towers were seen for as long as 3.5 weeks.

The dust towers that form during these storms are warmed by the Sun and rise high into the atmosphere. Scientists think that water molecules that form Mars' wispy clouds get trapped in all that dust, and are carried high into the atmosphere.

It's similar to how a thunderstorm cloud forms during a powerful storm on Earth. But at high altitudes on Mars, solar radiation breaks apart the H₂O molecules. These dust towers might explain, at least partially, how Mars lost its water over billions of years[2].

[1] Heavens et al: Dusty Deep Convection in the Mars Year 34 Planet-Encircling Dust Event in JGR Planets – 2019. See here.
[2] Heavens et al: Hydrogen escape from Mars enhanced by deep convection in dust storms in Nature Astronomy – 2018. See here.