ESA’s Mars Express orbiter has observed several local and regional dust storms brewing at the north pole of the Red Planet.
Local and regional storms lasting for a few days or weeks and confined to a small area are common place on Mars, but at their most severe can engulf the entire planet, as experienced last year in a global storm that circled the Red Planet for many months.
It is 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.
ESA’s Mars Express 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.
The two cameras onboard the spacecraft, the High Resolution Stereo Camera and the Visual Monitoring Camera, have been monitoring the storms over the last weeks.
The orbiter observed that when the dust storms reached the Martian volcanoes Elysium Mons and Olympus Mons, orographic clouds — water ice clouds driven by the influence of the volcano’s leeward slope on the air flow — that had previously been developing started to evaporate as a result of the air mass being heated by the influx of dust.
These dust storms only last a few days; the elevated dust is transported and spread out by global circulation into a thin haze in the lower atmosphere, around 12.5-25 miles (20-40 km) altitude.
Some traces of dust and clouds remained in the volcanic province into mid-June 2019.