Didn't you know about the global dust storm Mars is experiencing right now? Can take weeks, even months, for the dust to settle even after the big blow is over. Current event has been on for a few weeks now. Mars obviously knew we were looking and got camera shy
Below is the same sort of global dust event from 2001.
NASA has concerns for its rover on the Martian surface that the dust that settles on the solar panels will be too much for the rover to power up.