Evolution of a Geomagnetic Storm

The animation shows forecast snapshots every three hours of auroral Hall conductivities for the May 4, 1998, storm. The electrojet location and intensity forecasts provide high quality impact assessment information to electric utilities. This series of snapshots provides a northern hemisphere view of the evolution of the storm. The time shown is universal time (GMT). Significant power system impacts were caused by this storm in the northeast US. The electrojet patterns show the impact areas of the storm and are forecast approximately 45 minutes in advance, allowing lead time for storm operational preparation.