<p>&#160;&#160;&#160;&#160;&#160; Major dust storms &#8211; including large regional and global dust storms &#8211; dramatically influence atmospheric optical depth, thermal structure, and circulation. They represent probably the most significant inter-annual variability in the Martian lower / middle atmosphere and are of particular concern for spacecraft missions. Great variability is exhibited not only in their timing and magnitudes, but also in histories of their evolution. Mars Daily Global Maps (MDGMs) over the past Mars decade have shown that all major dust storms develop through a combination of dust storm sequences evolving along one or more trajectories, where each dust storm sequence is composed of multiple dust storm members of various sizes and durations along a trajectory. In this presentation, we will illustrate the trajectories of major dust storms observed in MDGMs and examine their relationship with the general circulation.</p>