A severe G4-scale geomagnetic storm hit Earth this morning, causing auroras to be visible in more than a dozen states near the U.S.-Canada border. The storm, which followed powerful solar eruptions, has since subsided but mild geomagnetic activity continues. This type of storm can have adverse effects on satellites, power grids, and radio communication systems, but most impacts can be mitigated with advanced warning.
NOAA first recorded G4-class storm conditions on Monday morning, with the storm weakening afterwards. A moderate G2-class storm is expected to persist until Wednesday. Geomagnetic storms occur when charged solar plasma from coronal mass ejections (CMEs) collide with Earth’s magnetic field, causing charged solar particles to excite molecules in the atmosphere and create auroras.
Solar activity has been high recently, with the sun launching multiple CMEs towards Earth since August 10. Some of these CMEs triggered widespread auroras over the weekend, with sightings reported as far south as Texas, Arizona, and Colorado. Tonight’s auroral display may be visible in states such as Washington, Idaho, Montana, North and South Dakota, Minnesota, and others. To view auroras, it is best to go to areas far from artificial light sources.
NOAA measures geomagnetic storms on a scale from G1 (minor) to G5 (extreme). In May, an extreme G5-scale storm hit Earth, causing temporary satellite malfunctions and power grid irregularities. CME outbursts and geomagnetic storms are more common during the solar maximum period of the sun’s 11-year cycle. The current solar cycle’s maximum was initially predicted to begin in 2025, but some researchers believe it may have already started.
Brandon, the space/physics editor at Live Science, writes about space, geoscience, and the mysteries of the universe. His work has been featured in various publications, and he holds a degree in creative writing with minors in journalism and media arts. Auroras are a fascinating natural phenomenon that can be enjoyed by skywatchers in certain regions during geomagnetic storms like the one that occurred today.
