Martian dust devils, which can tower five to six miles (eight to ten kilometers) tall, form when summer heat gets the ground warmer than the air above it. As warm air close to the ground rises, plumes of cooler air fall to replace it, creating vertical circulation. If a gust of wind blows through, it can send the circulating air spinning horizontally, triggering a dust devil. The pictured dust plume's shadow suggests it reaches more than 0.5 mile (0.8 kilometer) high.
Dust Devils on Mars are very electrical. They have a white lightning flash at their base and they also leave a dark scar along the surface. These Martian Devils are huge (up to 10km high) which is weird for a planet with very little atmosphere. The dust storms that can cover the entire surface and atmosphere of Mars start in a crater and slowly build up.
Amazing Dust Storm on Mars - Scientists recently were amazed at the photos of the dust devils from Mars shown. The photos were captured by the Mars Reconnaissance Orbiter that has been sending photos of Mars to astronomers here on Earth. The dust devil shown in the photo was 100 feet wide. The dust devils will be a major problem if astronauts are to visit Mars. The dust devils can be up to 10 times larger than earth tornados and rotate at 70 miles an hour.
Valles Marineris: The Grand Canyon of Mars Credit: Viking Project, USGS, NASA The largest canyon in the Solar System cuts a wide swath across the face of Mars. Named Valles Marineris, the grand valley extends over 3,000 kilometers long, spans as much as 600 kilometers across, and delves as much as 8 kilometers deep. By comparison, the Earth's Grand Canyon in Arizona, USA is 800 kilometers long, 30 kilometers across, and 1.8 kilometers deep.