The origin and evolution of Saturn's 2011-2012 stratospheric vortex

► Saturn's storm produced huge perturbations to stratospheric temperatures and winds. ► Two beacons of emission merged to form a large stratospheric vortex in May 2011. ► Temperatures within the vortex were enhanced by 80 K compared to the surroundings. ► The vortex is a long-lived feature, moving west and slowly cooling and shrinking. ► Waves from the storm transported energy into the stratosphere to form the beacons.