In May 2024 a powerful solar eruption, dubbed the Gannon storm, sent intense radiation and ionized gas toward Earth. While the event produced spectacular auroras across all 50 states and distant locations such as the Bahamas, it stopped short of causing widespread blackouts. Nevertheless, the storm disrupted satellite services, forced airlines to reroute, and damaged precision GPS sensors used by farmers in at least 12 states, leading to estimated economic losses between $500 million and $1 billion.
New research published in the journal AGU Advances provides the most detailed projection to date of how a far stronger solar event could affect the United States. Led by Ed Oughton of George Mason University, the study models a Carrington‑level geomagnetic storm—an event that occurs roughly once every 150 years—or even rarer 250‑year storms, and evaluates the resulting impacts on the nation’s high‑voltage transmission network.
Modeling a Carrington‑Level Event
The researchers built engineering models of the U.S. grid, incorporating 10,464 substations and 16,256 transmission lines. Because the actual grid layout is classified for security reasons, the team used publicly available data and varied network configurations to simulate how induced electric fields would flow during a massive solar storm. Dennies Bor, a co‑author, explained that rapid changes in Earth’s magnetic field generate ground‑level electric fields, which drive currents through grounded transmission lines and transformers. Excess current can push transformers into an unbalanced state, forcing them to draw more power to maintain voltage. If the system cannot meet demand, voltage drops and protective devices may isolate sections of the grid, leading to outages.
Historical context underscores the seriousness of the threat. On March 13 1989, a solar storm knocked out power to Quebec, leaving six million people in darkness for nine hours, and caused damage to two U.S. substations on the East Coast. That event was stronger than the Gannon storm but still far weaker than the 1859 Carrington Event, which disrupted telegraph systems worldwide.
Regional Vulnerabilities and Economic Risks
The study’s simulations identify the Northeast and the Northern Plains as the most susceptible regions. High‑latitude locations receive stronger geomagnetic disturbances, and the underlying bedrock in these areas is highly resistive, preventing induced currents from dissipating into the Earth’s core. The eastern interconnection’s tightly linked network means a voltage problem in one state—such as Maine—could cascade across the corridor to Washington, D.C.
Economic modeling suggests a 250‑year storm could generate between $1.5 billion and $2 billion in losses per day, combining direct damage and downstream supply‑chain effects. The researchers estimate power disruptions would affect roughly 5.1 million people and 135 000 businesses, with manufacturing, education and entertainment sectors bearing the heaviest burdens. A Carrington‑level event could therefore impose near‑$2 billion in daily losses across the nation.
Implications for Grid Preparedness
Despite the dire projections, the authors stress that the grid is not defenseless. Grid operators receive advance warnings from agencies such as the Space Weather Prediction Center, where Shawn Dahl described the magnetic “rubber bands” that snap in sunspots and launch plasma toward Earth. Dahl noted that solar activity is currently declining, but warned that preparation is needed for storms three times more powerful than Gannon.
Anna Kelbert, a geophysicist at the Harvard‑Smithsonian Center for Astrophysics who was not involved in the study, emphasized that severe geomagnetic storms do not follow a predictable schedule; they could arrive within a week or centuries from now. The study concludes that the United States is presently ill‑prepared for a major magnetic storm, and that the societal impacts would be catastrophic without substantial upgrades to grid resilience and emergency response planning.
As the planet’s magnetic environment continues to evolve, the research offers a crucial roadmap for policymakers, utilities and emergency managers seeking to safeguard the nation’s electricity supply against one of nature’s most powerful threats.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
