The US National Oceanic and Atmospheric Administration (NOAA) issued a rare “Severe” G4 Geomagnetic Storm Watch from Friday through the weekend after a series of massive solar flares sent waves of plasma and high-energy radiation hurtling toward the Earth. The administration’s warning—the first such alert issued in nearly 20 years—suggests that the atmospheric phenomenon could lead to disruptions in communications and power grids across the country.
In a press release on Thursday, NOAA reported that several gigantic sunspots (temporary areas of the sun that are darker and proportionately cooler than the rest of the solar surface) merged into a cluster and spit out multiple radioactive solar flares. The sunspot cluster is estimated to be approximately 16 times the diameter of Earth.
The resulting coronal mass ejections (CMEs), consisting of superheated plasma particles and x-rays, are now moving quickly toward Earth’s atmosphere, where they could potentially wreak havoc on the planet’s communication infrastructure.
The last time NOAA issued a “severe” warning was in 2005 when a similar solar event blanked the Earth in the highest dose of radiation in half a century. The strongest geomagnetic storm in history, known as “the Carrington Event,” hit the earth in 1859. That storm was categorized as a G5, one class higher than the storm expected to arrive this weekend.
Large sunspot groups and strong solar flares led to the issuance of SWPC's first G4 Watch since 2005… pic.twitter.com/oi55cTPXhP
— NOAA Space Weather Prediction Center (@NWSSWPC) May 9, 2024
The geomagnetic storms that ensue when solar radiation collides with the planet’s atmosphere can cause voltage issues, disrupting power grids, GPS navigation, and radio communications while also posing a risk to orbiting satellites floating outside Earth’s protective atmospheric layer.
“Geomagnetic storms can impact infrastructure in near-Earth orbit and on Earth’s surface, potentially disrupting communications, the electric power grid, navigation, radio and satellite operations,” NOAA said. “[The Space Weather Prediction Center] has notified the operators of these systems so they can take protective action.”
Though the risk to power and communication infrastructure is cause for concern, a storm of this magnitude also offers a rare chance for the mystifying Northern Lights to be seen much farther south than would normally be possible. Under these conditions, the aurora borealis, caused by glancing blows from solar winds across the planet’s poles, could potentially be seen as far away as Alabama. During the Carrington Event, the lights were seen as far south as Cuba and Hawaii.
NOAA clarified that there are an average of 100 severe geomagnetic storms in an average 11-year solar cycle (most of them directed away from the Earth), but only three have been observed since the cycle that began in December 2019.
If the solar flares manage to reach the planet, the early effects of the geomagnetic radiation could be felt as early as noon on Friday.
High-Risk Solar Storm Forecast – Total Analysis pic.twitter.com/yx2Thz6XGT
— SpaceWeatherNews (@SunWeatherMan) May 9, 2024
