Largest dust storm on Mars ever recorded
According to Leah Crane from New Scientist online website, dust storms on Mars aren’t all about dust — they’re also full of water. In 2018, the largest recorded dust storm circled the entire Martian globe, so thick that it hid the surface from the sun and killed the Opportunity rover. The ExoMars Trace Gas Orbiter watched this cataclysmic storm from orbit. Just before sunset and just after sunrise on Mars, it examined the atmosphere to determine how the dust storm absorbed sunlight. Just before the storm, there were water ice clouds in the atmosphere, but no water vapour more than 40 kilometres above the surface. This changed a few days later when water vapour appeared at altitudes of 40 and 80 kilometres, seemingly replacing the water ice clouds.
This probably occurs because the dust absorbs heat, warming up the atmosphere and making it circulate more strongly, which prevents the formation of ice clouds.
How bad are the dust storms on Mars?
According to CoolCosmos, Mars is famous for its large, planet-wide dust storms. Mars has an atmosphere which is much thinner than the atmosphere on Earth, but which still creates winds. When these winds pick up the fine, dry particles of dust on Mars, a dust storm can occur. Most dust storms cover an area for a few days and carry small particles of dust at speeds of 33 to 66 miles per hour. Sometimes, though rarely, dust storms on Mars can be fierce enough to cover the entire planet in a dusty haze for weeks.