Fig. 1From: Extreme geomagnetically induced currentsEmergency alert framework for geomagnetically induced currents. The equatorward boundary of the auroral oval according to the model of Yokoyama et al. (1998) is shown by the solid curve, and the dotted curve shows its theoretical extrapolation. It is important to update the possible extension of the auroral oval toward middle to low latitudes during extreme magnetic stormsBack to article page