The US National Oceanic and Atmospheric Administration warns that a severe geomagnetic storm caused by solar flares could disrupt communications and other infrastructure.
Solar flares are bursts of energy on the sun's surface that can release large amounts of charged particles. NOAA says a coronal mass ejection occurred this month and reached the Earth on Thursday.
The agency says geomagnetic storm conditions are at their second-highest level on a scale of five, but they could intensify. It warns that the storm could affect some radio communications, GPS services and power grids.
NOAA adds that aurorae could be visible at lower latitudes than usual. Solar activity changes in 11-year cycles, and has been sharply increasing this year.
In May, aurorae were observed in many parts of the world, including Japan, due to the impact of solar flares. The phenomenon also affected economic activities, including apparent disruptions to GPS-based services.
