Multiple-step geomagnetic storms and their interplanetary drivers

While the classic picture of a geomagnetic storm is of a main phase eventually reaching maximum intensity, followed by a recovery, the profile can often be more complex. This has been recognized in past studies that have classified storms as having one'' or two'' steps'' during the main phase. However, the intense ( Dst <= -100 nT) storms studied during the LWS CDAW Workshop may be more complicated. We discuss the variety of interplanetary circumstances that gave rise to several storms of varying complexity.