HiRISE: The draa of Mars

Sandy landforms formed by the wind or aeolian bedforms are classified by the wavelength–or length–between crests. On Mars we can observe four classes of bedforms (in order of increasing wavelengths): ripples, transverse aeolian ridges (known as TARs), dunes, and what are called “draa.” All of these are visible in this Juventae Chasma…. [More at link]