We report observations of large-amplitude Pc5 magnetic pulsation events on three successive orbits of the Explorer 45 satellite near L = 5 in the afternoon quadrant during the June 1972 geomagnetic storm. In each case, waves occur during a period of depressed magnetic field coinciding with a plasma injection event. The resulting waves have a significant compressional component and appear to be quite localized in longitude. Polarization analysis indicates that in two cases the satellite appears to have crossed the resonant field line of the observed waves. Variations in electron and proton energy density, where available, correlate well with the observed magnetic variations. The observations lend credence to earlier generalizations that storm time Pc5 pulsations are generated by newly injected hot plasma via local plasma instabilities and manifest themselves as coupled hydromagnetic waves with compressional and field line resonant transverse components.