Portland, Maine – A rare G4 (Severe) geomagnetic storm is expected to affect Earth on Jan. 20, prompting heightened monitoring of Maine’s power grid and other critical systems as federal space weather officials track incoming solar activity.
According to the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center, a coronal mass ejection (CME) launched from the Sun late last week is forecast to arrive late Sunday into Monday. G4-level geomagnetic storms are uncommon and can interfere with power transmission systems, satellite operations, GPS accuracy, and some radio communications, particularly in higher-latitude regions such as northern New England.
Maine is among the states most exposed to geomagnetic effects due to its latitude and reliance on long-distance transmission lines that carry electricity across rural areas. While NOAA officials emphasize that widespread power outages are not expected, utilities typically increase monitoring during severe space weather events to protect transformers and maintain grid stability.
For most residents, the solar storm itself will not be noticeable. Experts explain that the primary concern is not direct disruption, but the way geomagnetic activity can reduce the power grid’s margin for error, especially during periods of elevated demand. Grid operators may take precautionary actions, including load balancing and equipment protection, if conditions intensify.
Cell phone service and internet connectivity are expected to remain largely unaffected. Some users may experience minor GPS inaccuracies, particularly in aviation, marine navigation, and precision timing applications.
As a visible side effect, auroras may be visible across much of Maine, potentially extending farther south than usual if storm conditions strengthen.
Geomagnetic activity could persist at lower levels into Tuesday, according to NOAA forecasters.
