Dimming evolution for 6 September, 2011 event (a) at the maximum of the impulsive phase (12 min from the start of the event), (b) 30 min from the start of the event, (c) at the end of the impulsive phase (44 min after the maximum of the impulsive phase), and (d) 2.5 h from the start. The blue lines show 12 angular sectors, and the color bar indicates when each dimming pixel was first detected.