Mars’ Exploration Rover Opportunity took the image using its navigation camera (Navcam) on March 31, 2016, during the 4,332nd martian day, or sol, of the rover’s work on Mars.
Dust devils were a common sight for Opportunity’s twin rover, Spirit, in its outpost at Gusev Crater. Dust devils have been an uncommon sight for Opportunity, though.
Just as on Earth, a dust devil is created by a rising, rotating column of hot air. When the column whirls fast enough, it picks up tiny grains of dust from the ground, making the vortex visible.
During the uphill drive to reach the top of Knudsen Ridge, Opportunity’s tilt reached 32°, the steepest ever for any rover on Mars.