Dust Storms

Wind Pattern and Temperatures on Mars

On Mars, dust storms are not a rare occurrence. They are much like a fine mist or fog being swirled around by 100 plus mph winds. In contrast, on Earth in the Sahara and Mojave Deserts, the sand is much thicker and coarser and can do more damage. Mars Pathfinder has found that the Martian soil is finer than talcum powder. So terrestrial sand storms are more serious than the Martian ones. Above is a partial map of wind patterns and temperature on Mars (courtesy CMEX Laboratories). Martian dust storms usually start in the southern hemisphere, during summer time. In the summer, heat escapes from the surface very rapidly. Since the southern hemisphere is closest to the sun during the summer, it receives the most direct heat. The storms usually work their way up to the north. Occasionally a dust storm will go global. During the Viking missions the landers both experienced many dust storms. The following series of images on the left were taken during the Viking 1 lander mission. They show regular days and nights, as well as harsh dust storm conditions on Sol. 1742. (sol 1742 means the 1742 solar cycle or day)

In the Fall of 1996 (Martian spring) a dust storm raged at the north pole of Mars while Earth had the Hubble Space Telescope pointed towards it. It captured these spectacular images (to get a bigger view click on the image). It shows the curly wisps of dust and sand. Every year there are hundreds of dust storms. From Earth based observations we only see the long ones or the global ones that occur 3 or 4 times a year.