Topline
An intense solar storm could disrupt communications and trigger flashy displays of the Northern Lights across large parts of the U.S. on Friday, the National Oceanic and Atmospheric Administration warned, the first alert of its kind in nearly 20 years after the sun sent several bursts of high energy plasma hurtling towards Earth.
Key Facts
A “severe” G4 geomagnetic storm could buffet the Earth from Friday evening, according to a watch alert issued by NOAA’s Space Weather Prediction Center late Thursday.
Geomagnetic storms are temporary disturbances to the Earth’s magnetic field caused by large expulsions of magnetic fields and plasma from the sun’s atmosphere, known as coronal mass ejections (CMEs).
G4 storms are the second-strongest kind of geomagnetic storm and are considered “severe,” capable of damaging satellites, causing “widespread voltage problems” and issues with the electric power grid, radio and navigation and potentially causing communications disruptions.
NOAA said the alert follows “at least five Earth-directed” CMEs that are expected to arrive as early as midday on Friday and could persist through Sunday.
The agency said it has not issued a watch alert for a geomagnetic storm of this magnitude since January 2005.
Geomagnetic storms can also trigger “spectacular displays of aurora on Earth,” known as the Northern Lights, which NOAA said could potentially be seen as far south as Alabama and Northern California.
Get Forbes Breaking News Text Alerts: We’re launching text message alerts so you’ll always know the biggest stories shaping the day’s headlines. Text “Alerts” to (201) 335-0739 or sign up here.
Crucial Quote
Solar activity is cyclical and intensity varies over a period of around 11 years. “G4 storms are relatively rare, with about 100 over the course of an 11-year solar cycle,” Rob Steenburgh, a space scientist at the SWPC, told Axios. Right now, we are “very close to a solar maximum, so we can expect frequent activity,” he explained, adding that “the strongest storms (G5) are the most rare, with only 4 during the course of an average solar cycle.” There were no G5 events during the last solar cycle, Steenburgh said.
Key Background
While the Earth’s magnetic field shelters us from the worst of the sun’s radiation, intense bursts can still cause disturbances on the ground as well as potentially harm less-protected assets like satellites or even astronauts in space. As such technology makes up a crucial part of our communications and navigation systems, disruptions can be expected during periods of high solar activity, which is also partly due to disturbances solar radiation can cause to the layers of the atmosphere GPS and communications signals travel through. On the ground, radiation monitors can also be expected to register higher readings, though NASA emphasizes harmful radiation from solar flares “cannot pass through Earth’s atmosphere to physically affect humans on the ground.”
Tangent
The last G5 geomagnetic storm, classified as “extreme,” occurred around Halloween in 2003. The storms affected over half of all Earth-orbiting spacecraft and intermittently disrupted satellite TV and radio services, NOAA said. They also forced astronauts aboard the International Space Station to take cover — something that had only happened twice before in the mission’s history — damaged a Japanese scientific satellite “beyond repair” and “sent several deep-space missions into safe mode or complete shutdown.” It also sparked communications problems on airline flights between North America and Asia flying over the North Pole, triggered a five-day communications blackout for researchers working in Antarctica and caused aurora sightings across the U.S. from California to Texas to Florida.
