Warning over solar storm that could give US rare view of northern lights

A ferocious solar storm powerful enough to knock out or disrupt satellite and communications systems, the power grid and radio signals was raging on Friday, space weather researchers warned.

The National Oceanic and Atmospheric Administration (Noaa) issued a rare warning for extreme G5 geomagnetic storm conditions when a solar outburst reached Earth on Friday afternoon, hours sooner than anticipated. The effects were due to last through the weekend and possibly into next week. The last extreme G5 event was in 2003.

Noaa alerted operators of power plants and spacecraft in orbit to take precautions, as well as the Federal Emergency Management Agency.

“For most people here on planet Earth, they won’t have to do anything,” said Rob Steenburgh, a scientist with the Space Weather Prediction Center.

The severity of the geomagnetic storm that has propelled multiple solar flares towards Earth in recent days also brings a spectacular bonus for sky watchers: a rare but stunning view of the aurora borealis, otherwise known as the northern lights, in places they are rarely seen in the US.

More commonly visible only in Alaska and Canada, the show could be visible overnight in states including California, Colorado, Missouri and Virginia, and perhaps as far south as Alabama.

According to the Noaa, a large sunspot cluster has produced several moderate to strong solar flares since Wednesday morning.

At least five coronal mass ejections (CMEs) of varying intensity, and consisting of electrified, magnetic gas, are expected to merge and arrive at Earth late on Friday or early Saturday, the agency said, prompting it to issue the first severe geomagnetic storm watch since January 2005.

“We have a very rare event on our hands,” Shawn Dall, Noaa’s senior space weather specialist, told a Friday press briefing.

“A series of CMEs are directed right towards us, some are catching up with others. These severe levels are pretty extraordinary, and critical infrastructure operators have been notified.”

The solar storm is classified as G4, the equivalent of a category four hurricane, and emanates from a large and magnetically complex sunspot cluster 16 times the diameter of Earth, located in an area of the sun called Noaa region 3664.

“The worst situation would be, historically, from 1859 and the Carrington event, when a CME arrived at Earth and extraordinary things happened,” Dall said. “We are not anticipating that, but we cannot discount a G5.”

Dall said a better indication of possible effect could come later on Friday when the ejections reach the European Space Agency’s L1 satellite at the first so-called Lagrange point in space.

“We won’t know until the CMEs arrive 1m miles from Earth. If we reach G4 there could well be some infrastructure effects,” he said.

The most recent event of similar or greater magnitude was the October 2003 “Halloween” G5 solar storms, which produced a multitude of what Nasa described as “ghostly looking auroras”, but which wreaked havoc with the global power grid, notably in Sweden and South Africa.

Like the 2003 storms, this week’s activity will produce a stunning celestial show of the northern lights in states as far south as Alabama.

The sunspot is visible from Earth to those with telescopes and cameras with special solar filters, or who have retained their safety glasses from last month’s total solar eclipse that traversed Mexico, much of the US, and Canada.

Despite its massive size, almost 125,000 miles across, the sunspot appears as a small dot on the sun’s surface.

Brent Gordon, the head of the space weather prediction service, said the solar event would last at least through Sunday.

“We’re not quite sure what to anticipate, although we do expect to see one shock arrival followed by possibly one or two others,” he said.

Associated Press contributed to this report