Charged particles flowing from the sun have touched off a strong geomagnetic storm across the Earth that can disrupt power grids, satellites and radio navigation systems.
Geomagnetic conditions increased early Tuesday before weakening by midday, according to the U.S. Space Weather Prediction Center. The event led the PJM Interconnection LLC, operator of the biggest U.S. power grid, and Midcontinent Independent System Operator, which manages high-voltage transmission lines across 15 U.S. states and one Canadian province, to issue warnings.
The storms can cause voltage corrections and trigger false alarms in some power system equipment, the Boulder, Colorado-based center said. They can also create drag on satellites in low-Earth orbits, forcing course corrections and disrupting navigation and high-frequency radio signals. The storm’s aurora can sometimes be seen as far south as Illinois and Oregon.
The space weather center had issued an alert earlier on Tuesday about a “serious” G3 level storm. They lowered it an hour later to a more “moderate” G2 level watch. PJM canceled its warning at 2 p.m. New York time.