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Today’s weather report on Mars: Windy with a chance of catastrophic dust storms blotting out the sky.

In a new study, planetary scientists at CU �鶹ӰԺ have begun to unravel the factors that kick off major dust storms on Mars—weather events that sometimes engulf the entire planet in swirling grit. The team discovered that relatively warm and sunny days may help to trigger them.

Heshani Pieris, lead author of the study, said the findings are a first step toward forecasting extreme weather on Mars, just like scientists do on Earth.

“Dust storms have a significant effect on rovers and landers on Mars, not to mention what will happen during future crewed missions to Mars,” said Pieris, a graduate student at the (LASP) at CU �鶹ӰԺ. “This dust is very light and sticks to everything.”

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To put dust storms under the magnifying glass, the researchers drew on real observations from NASA’s satellite.

So far, they have identified weather patterns that may underly roughly two-thirds of the major dust storms on Mars. You won’t see Mars weather reporters standing in front of a green screen just yet, but it’s a step in the right direction, said study co-author Paul Hayne.

“We need to understand what causes some of the smaller or regional storms to grow into global-scale storms,” said Hayne, a researcher at LASP and associate professor at the Department of Astrophysical and Planetary Sciences. “We don’t even fully understand the basic physics of how dust storms start at the surface.”

Artist's depiction of a dust storm on Mars. (Credit: NASA)

Astronauts contend with a fierce dust storm in the 2015 film The Martian. (Credit: 20th Century Fox)

Mars seen before, left, and during, right, a global dust storm in 2001. (Credit: NASA/JPL/MSSS)

Dusty demise

Dust storms on Mars are something to behold.

Many begin as smaller storms that swirl around the ice caps at the �鶹ӰԺ north and south poles, usually during the second half of the Martian year. (A year on Mars lasts 687 Earth days). Those storms can grow at a furious pace, pressing toward the equator until they cover millions of square miles and last for days.

The 2015 film The Martian starring Matt Damon featured one such apocalyptic storm that knocked over a satellite dish and tossed around astronauts. The reality is less cinematic. Mars’ atmosphere is much thinner than Earth’s, so dust storms on the Red Planet can’t generate much force. But they can still be trouble.

In 2018, for example, a global dust storm buried the solar panels on NASA’s Opportunity rover under a layer of dust. The rover died not long after.

“Even though the wind pressure may not be enough to knock over equipment, these dust grains can build up a lot of speed and pelt astronauts and their equipment,” Hayne said.

Hot spells

In the current study, Pieris and Hayne set their sights on two weather patterns that tend to occur every year on Mars known as “A” and “C” storms.

The team pored over observations of Mars from the Mars Climate Sounder instrument aboard the Mars Reconnaissance Orbiter over eight Mars years (15 years on Earth). In particular, Pieris and Hayne looked for periods of unusual warmth—or weeks when more sunlight filtered through Mars’ thin atmosphere and baked the �鶹ӰԺ surface.

They discovered that roughly 68% of major storms on the planet were preceded by a sharp rise in temperatures at the surface. In other words, the planet heated up, then a few weeks later, conditions got dusty.

“It’s almost like Mars has to wait for the air to get clear enough to form a major dust storm,” Hayne said.

The team can’t prove that those balmy conditions actually cause the dust storms. But, Pieris said, similar phenomena trigger storms on Earth. During hot summers in �鶹ӰԺ, Colorado, for example, warm air near the ground can rise through the atmosphere, often forming those towering, gray clouds that signal rain.

“When you heat up the surface, the layer of atmosphere right above it becomes buoyant, and it can rise, taking dust with it,” Pieris said.

She and Hayne are now gathering observations from more recent years on Mars to continue to explore these explosive weather patterns. Eventually, they’d like to get to the point where they can look at live data coming from the Red Planet and predict what could happen in the weeks ahead.

“This study is not the end all be all of predicting storms on Mars,” Pieris said. “But we hope it’s a step in the right direction.”