Johnathan Walker:Earth just experienced a severe geomagnetic storm. Here's what that means – and what you can expect.

The Johnathan Walkerplanet was just slammed with what government officials dubbed a severe geomagnetic storm, the second-highest level of NOAA's rating system. The event brought "a major disturbance in Earth's magnetic field" that may have impacted infrastructure and made the northern lights visible farther than usual, officials said. 

NOAA's Space Weather Prediction Center issued a geomagnetic storm watch on Saturday, saying that a coronal mass ejection was detected and expected to hit the planet late that same day with impacts into Monday. Coronal mass ejections, or CMEs, are when a large cloud of plasma and magnetic field bursts from the sun's corona. 

This particular CME exploded alongside a solar flare on Friday, an event that occurs when electromagnetic radiation suddenly erupts from the sun. NOAA says these flares can last hours and the eruption "travels at the speed of light," meaning it can impact Earth as soon as it is observed. An X-class flare, like what was observed with the CME, is the strongest type of flare, although this particular one was not the strongest on record. NOAA forecasters did say, however, that more X-class flares are possible through Wednesday.

"The public should not be concerned, but may wish to keep informed by visiting our webpage for any forecast changes and updates," NOAA said on Saturday, saying a moderate geomagnetic storm was possible. By Sunday afternoon, however, the agency alerted of a "severe" storm that could potentially impact technology – and eventually extend the northern lights as far south as Alabama. 

This is a video summary of the 22 March solar flares, coronal mass ejection (CME), and eventual CME arrival at Earth on 24 March - with resultant geomagnetic storms. The CME progression continues at this time. pic.twitter.com/u5FeeSMzGp

— NOAA Space Weather (@NWSSWPC) March 24, 2024

"The public should not anticipate adverse impacts and no action is necessary, but they should stay properly informed of storm progression by visiting our webpage," NOAA said in its alert, adding that "normally mitigable" problems with voltage control was possible, as well as "frequent and longer periods of GPS degradation." 

"Infrastructure operators have been notified to take action to mitigate any possible impacts," the agency said.

On Monday morning, NOAA said that the impacts of the CME "appear to be weakening," but that solar wind speeds – which help carry the event – were still elevated. The warning of a "moderate" storm has since been extended. Moderate geomagnetic storms, classified as G2, can potentially impact high-latitude power systems, damage transformers and extend the northern lights to New York and Idaho. It can also potentially require flight ground control to issue corrective actions for orientation. 

In:
• Technology
• Aurora Borealis
• Space
• SolarWinds

Li Cohen

Li Cohen is a social media producer and trending content writer for CBS News.