This is a local dust storm on Mars located near the edge of the south polar cap. Click on image for full size version (158K GIF) Image from: Calvin J. Hamilton, LPI, and NASA

This image shows a local dust storm near the edge of the south polar cap. Viewing of this image at high resolution is recommended. This fascinating image shows dust swirling over a large area.

Martian global dust storms tend to start in the southern hemisphere with a local dust storm, such as the one shown here. Southern spring and summer seem to be the season for global dust storms. Local dust storms seem to be swept into huge storms which envelope the entire planet, as was discovered by the Viking mission to Mars in the 1970's. Global dust storms do not seem to occur every Martian spring or summer, however.

The action of sands carried by winds during Martian global dust storms makes a great contribution toward wearing down rocks on the Martian surface.