We investigate the rare events of sudden appearances of relativistic electrons (>700 keV), which are normally confined to the Van Allen belts, in the slot region. The frequency of occurrence of these events are on average 1-2 per year. To cope with the scarcity of events, in this study we examine 21 years of trapped relativistic electron fluxes available from the POES and MetOp Space Environment Monitor (SEM‐2). Our statistical analysis show that these events can occur even during moderate geomagnetic activity. Occurrence of these events correlates with high speed solar winds or ICMEs depending on the phase of the solar cycle. Most importantly, we show that ULF wave activity plays a significant role in causing these events and the events could be predicted in 75% of the cases.