San Francisco, California – A G4 (Severe) geomagnetic storm, in effect for Jan. 20, is expected to reach Earth, prompting heightened monitoring of technology and critical infrastructure across the West Coast, according to federal space weather officials.
The National Oceanic and Atmospheric Administration’s Space Weather Prediction Center says a coronal mass ejection, or CME, launched from the Sun late last week is forecast to arrive late Sunday into Monday. Severe geomagnetic storms can disrupt satellite operations, GPS accuracy, radio communications, and long-distance power transmission systems, though impacts vary by region.
The storm watch includes California, Oregon, Washington, and parts of western Nevada, where coastal population centers rely on extensive transmission networks and satellite-supported systems for navigation, communications, aviation, and emergency response. While the West Coast sits south of the regions most vulnerable to geomagnetic disturbances, officials say G4-level storms warrant increased monitoring due to the scale and complexity of regional infrastructure.
NOAA officials emphasize that widespread power outages are not expected. However, utilities and operators of critical systems typically implement precautionary measures during severe space weather events, including enhanced grid monitoring and protection of sensitive equipment.
For most residents, the solar storm will not produce noticeable impacts on daily life. Cell phone service and internet connectivity are expected to remain largely unaffected. Some users may experience minor GPS inaccuracies, particularly affecting aviation operations, marine navigation, surveying, and precision timing systems.
Aurora displays are unlikely along most of the West Coast, though faint visibility may be possible in far northern areas if storm conditions intensify beyond current forecasts.
Geomagnetic activity could gradually ease into Tuesday as space weather conditions stabilize.
