The European Space Agency’s (ESA) Mars Express spacecraft has been monitoring dust storms brewing at Mars’ north pole over the last month, and watching as the storms disperse toward the equator. The spacecraft observed at least eight different storms at the edge of the ice cap between May 22 and June 10, 2019, which formed and dissipated very quickly, between one and three days.
It’s currently spring in the northern hemisphere of Mars, and water-ice clouds and small dust-lifting events are frequently observed along the edge of the seasonally retreating ice cap. Local and regional storms lasting for a few days or weeks and confined to a small area are common on Mars, but at their most severe they can engulf the entire planet, as experienced last year in a global storm that circled the planet for many months.
Both Mars Express and NASA’s Mars Reconnaissance Orbiter observed that when the dust storms reached the large volcanoes Elysium Mons and Olympus Mons, orographic clouds – water ice clouds driven by the influence of a volcano’s leeward slope on the air flow – that had been developing, started to evaporate as a result of the air mass being heated by the influx of dust.
These regional dust storms only last a few days. The planet’s circulation moves the elevated dust and spreads it out into a thin haze in the lower atmosphere. Some traces of dust and clouds remained in the volcanic province into mid-June.
Bottom line: Images of dust storms at the Mars north pole, take by ESA’s Mars Express.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.