Chicago, Illinois – A rare G4 (Severe) geomagnetic storm, in effect for Jan. 20, is expected to reach Earth as an intense Arctic air mass drives dangerous cold across the Midwest, increasing scrutiny on power systems and other critical infrastructure during a period of peak demand.
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. G4 geomagnetic storms are uncommon and can disrupt power transmission systems, satellite operations, GPS accuracy, and some radio communications, particularly across regions with long-distance transmission lines.
The storm watch spans much of the Midwest, including Illinois, Indiana, Ohio, Michigan, Wisconsin, Minnesota, Iowa, and Missouri. While officials emphasize that widespread power outages are not expected, the timing is notable as Arctic air is forecast to push temperatures well below zero in parts of the Upper Midwest, with wind chills potentially falling to –16 degrees or colder.
For most residents, the solar storm itself will go unnoticed. Experts note that the primary concern is the overlap with extreme cold, which sharply increases electricity demand and reduces the grid’s margin for error. During geomagnetic storms, elevated electrical currents can place additional stress on transformers and transmission systems, prompting utilities to increase monitoring and take precautionary steps.
Residents are encouraged to focus on standard cold-weather preparedness, including keeping electronic devices charged, preparing vehicles for winter travel, and checking heating systems. Cell phone service and internet connectivity are expected to remain largely unaffected.
As a side effect, auroras may become visible farther south, potentially reaching northern portions of the Midwest if geomagnetic conditions intensify.
Geomagnetic activity may gradually ease into Tuesday, even as the coldest air settles across the central United States.
