The WIND, GEOTAIL, and GOES 9 spacecraft were all in the nightside magnetosphere and Interball was in the solar wind when a substorm began at ~07:25 UT on April 18, 1996. WIND and GEOTAIL were located at downstream distances of X=-12 to -14 Re. The separation between these spacecraft was ~10 Re in the Y direction and less than ~1 Re in Z. While the northward field component at GOES 9 began to increase immediately, little or no dipolarization was observed at WIND and GEOTAIL until a series of very rapid Bz increases were observed ~25--30 min later. About ~1--2 min prior to each dipolarization event at WIND and GEOTAIL an earthward flow burst with peak speeds of 100--500 km/s was initiated. The duration of these bursty bulk flows were 1--7 min. These unique observations are interpreted as strong evidence for the existence of spatially localized, but sometimes temporally overlapping flow bursts in the near-tail during substorm expansion phase which result, cumulatively, in sufficient earthward magnetic flux transport to produce the well known dipolarization at geosynchronous orbit.¿ 1997 American Geophysical Union