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Arthur T Knackerbracket has found the following story:

Dust storms are common on Mars. But every decade or so, something unpredictable happens: A series of runaway storms breaks out, covering the entire planet in a dusty haze.

Last year, a fleet of NASA spacecraft got a detailed look at the life cycle of the 2018 global dust storm that ended the Opportunity rover's mission. And while scientists are still puzzling over the data, two papers recently shed new light on a phenomenon observed within the storm: dust towers, or concentrated clouds of dust that warm in sunlight and rise high into the air. Scientists think that dust-trapped water vapor may be riding them like an elevator to space, where solar radiation breaks apart their molecules. This might help explain how Mars' water disappeared over billions of years.

Dust towers are massive, churning clouds that are denser and climb much higher than the normal background dust in the thin Martian atmosphere. While they also occur under normal conditions, the towers appear to form in greater numbers during global storms.

A tower starts at the planet's surface as an area of rapidly lifted dust about as wide as the state of Rhode Island. By the time a tower reaches a height of 50 miles (80 kilometers), as seen during the 2018 global dust storm, it may be as wide as Nevada. As the tower decays, it can form a layer of dust 35 miles (56 kilometers) above the surface that can be wider than the continental United States.

The recent findings on dust towers come courtesy of NASA's Mars Reconnaissance Orbiter (MRO), which is led by the agency's Jet Propulsion Laboratory in Pasadena, California. Though global dust storms cloak the planet's surface, MRO can use its heat-sensing Mars Climate Sounder instrument to peer through the haze. The instrument is designed specifically for measuring dust levels. Its data, coupled with images from a camera aboard the orbiter called the Mars Context Imager (MARCI), enabled scientists to detect numerous swelling dust towers.

[...] "Global dust storms are really unusual," said Mars Climate Sounder scientist David Kass of JPL. "We really don't have anything like this on the Earth, where the entire planet's weather changes for several months."

With time and more data, the MRO team hopes to better understand the dust towers created within global storms and what role they may play in removing water from the Red Planet's atmosphere.

More information: Nicholas G. Heavens et al. An Observational Overview of Dusty Deep Convection in Martian Dust Storms, Journal of the Atmospheric Sciences (2019). DOI: 10.1175/JAS-D-19-0042.1

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