The erosion of the plasmasphere during a storm is analyzed using the Naval Research Laboratory Sami3 is Also a Model of the Ionosphere ionosphere/plasmasphere code, coupled to the Rice Convection Model of the inner magnetosphere and ring current. We reproduce the commonly observed poststorm plasmasphere profile, with strong erosion outside of a sharp, poststorm plasmapause, and weak erosion inside the plasmapause. We find that inclusion of the ring current E field sharpens the poststorm plasmapause. In the case of a weak storm, erosion inside the poststorm plasmapause might not occur. In all cases, plasma flows are dominated by E × B drifts. For strong storms, we find that erosion, both inside and outside of the poststorm plasmapause, is caused by outward E × B drifts.