South Polar Dust Storm

Caption NASA:"This nearly global mosaic of observations made by the Mars Color Imager on NASA's Mars Reconnaissance Orbiter on April 2, 2009, shows billowing clouds of dust being lifted into the Atmosphere by a storm near the edge of the Seasonal Polar Cap of Southern Mars.
The season on Southern Mars is late Spring. Late Southern Spring and early Southern Summer are a peak time of the Martian year for major Dust Storms.
Atmospheric haze due to suspended dust from recent storm activity is evident elsewhere on the Planet, including the Skies over Mars rovers Opportunity (MER-B) and Spirit (MER-A).
Black areas in the mosaic are the result of data drops or high angle roll maneuvers by the Orbiter that limit the camera's view of the Planet.
Equally-spaced blurry areas that run from South-to-North (bottom-to-top) result from the high off-nadir viewing geometry, a product of the spacecraft's low-orbit.

Malin Space Science Systems, San Diego, provided and operates the Mars Color Imager. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the Spacecraft".