The disruption of the surface by the avalanching materials is thought to cause them to appear darker than their surroundings, just as the 1997 bouncing of Mars Pathfinder's airbags and the tire tracks made by the Sojourner rover left darkened markings indicating where the martian soil had been disrupted and disturbed. The arrows in the April 2001 picture indicate eight new streaks that formed on these slopes in Lycus Sulci since August 1999. This picture captures two dust storms, each large enough to cover Arizona or New Mexico. One is located near the lower left, the other at the lower right. Hellas Planitia is the dominant elliptical feature just below the center of the picture.
North is up and sunlight illuminates the area from the upper left.
The approximately 500 kilometer-wide circular feature just above the center is the crater Huygens. This feature is a dust devil. Dust devils are spinning, columnar vortices of wind that move across the landscape, pick up dust, and look somewhat like miniature tornadoes. Dust devils are a common occurrence in dry and desert landscapes on Earth as well as Mars. When this dust devil was spied in Amazonis Planitia on April 10th, the MOC was looking straight down.