The study underscores the growing threat of solar storms to the U.S. power grid. A geomagnetic storm similar to the 1989 event in Québec could cause widespread blackouts, particularly in the eastern U.S., where underground geology amplifies geoelectric fields. Prolonged exposure to these fields can overload transformers, leading to costly and time-consuming repairs. The new electrical map enhances the ability to predict and mitigate these risks, offering a critical tool for emergency planning and infrastructure protection.