Minneapolis, Minnesota – A rare G4 (Severe) geomagnetic storm, in effect for Jan. 20, is expected to reach Earth as dangerous Arctic cold grips the Upper Midwest, increasing concern around power reliability and other critical infrastructure during a period of extreme demand.
According to the NOAA Space Weather Prediction Center, 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 interfere with power transmission systems, satellite operations, GPS accuracy, and some radio communications, particularly in higher-latitude regions like the Upper Midwest.
The storm watch includes Minnesota, Wisconsin, Michigan, North Dakota, and South Dakota, where long-distance transmission lines and northern geography increase exposure to geomagnetically induced electrical currents. While NOAA officials stress that widespread power outages are not expected, the timing coincides with an Arctic outbreak forecast to drive temperatures well below zero, with wind chills potentially dropping to –16 degrees or colder across parts of the region.
For most residents, the solar storm itself will not be noticeable. However, experts emphasize that geomagnetic activity can reduce the power grid’s margin for error at a time when electricity demand is surging for heating. Utilities typically increase monitoring during such events and may take precautionary measures to protect sensitive equipment.
Residents are encouraged to focus on standard extreme-cold preparedness, including keeping electronic devices charged, preparing emergency heating plans, and limiting unnecessary travel during the coldest periods. Cell phone service and internet connectivity are expected to remain largely unaffected.
As a secondary effect, auroras may be visible across much of the Upper Midwest, potentially reaching farther south than usual if storm conditions intensify.
Geomagnetic activity could persist at lower levels into Tuesday, even as the coldest air settles across the northern Plains and Upper Midwest.
