SADs are dark, finger-like plasma voids that are sometimes observed descending through the hot, dense plasma above bright coronal loop arcades during solar flares. They were first reported for a flare and associated coronal mass ejection that occurred on January 20, 1999, and was observed by the SXT onboard Yohkoh. SADs are sometimes referred to as “ tadpoles ” for their shape and have since been identified in many other events (e.g.). They tend to be most easily observed in the decay phases of long-duration flares, when sufficient plasma has accumulated above the flare arcade to make SADs visible, but they do begin earlier during the rise phase. In addition to the SAD voids, there are related structures known as supra-arcade downflowing loops (SADLs). SADLs are retracting (shrinking) coronal loops that form as the overlying magnetic field is reconfigured during the flare. SADs and SADLs are thought to be manifestations of the same process viewed from different angles, such that SADLs are observed if the viewer's perspective is along the axis of the arcade (i.e. through the arch), while SADs are observed if the perspective is perpendicular to the arcade axis.