Spirit has shot several images of dust devils in the past few weeks. As far back as early March, one such bandit even passed over the rover and cleaned off its solar panels, boosting the available power supply by about 50 percent. On April 15th and April 18th, two different dust devils were imaged by the aging rover. This image links to a short animation showing them pass through the scene.
Dust devils are seasonal phenomena in Gusev Crater, which is why Spirit is seeing them crop up so frequently. Views like these will help scientists make better models for how the wind interacts with the Martian surface.
Halfway around the red planet, Opportunity is in a bit of a jam. It's currently stopped and its six wheels are buried deep in a sand pit. While this isn't immediate cause for alarm, rover team members are studying the situation to determine the best escape strategy. "We're planning on spending several days, maybe weeks there," says rover project scientist Joy Crisp (NASA/Jet Propulsion Laboratory). "We're being ultracautious and careful."