Ionospheric equivalent currents during the main phase of the St Patrick’s Day storm, 17 March 2015, from 17:28 UT until 18:10 UT. The left panel shows the evolution of the eastward (red) and westward electrojets (blue) as a function of latitude. The vertical dashed and solid orange lines give the times outside and inside the westward electrojets respectively. The six panels on the right display the total equivalent currents at the time before (panels 1, 3, 5) each of the three electrojet enhancements and at its maximum development (panels 2, 4, 6). The white dots highlight the magnetometer stations that record the B_X spikes in contrast to the close by stations that did not recorded any strong perturbations (black dots). On each of the six panels, the purple dots show the remaining stations for comparison.