A severe solar storm smacked Earth with a surprisingly big geomagnetic jolt Tuesday, potentially affecting power grids and GPS tracking while pushing the colorful northern lights farther south, federal forecasters said.
In a statement released early on Wednesday, The Space Weather Prediction Center in Boulder, Colorado said that the geomagnetic storm had subsided. “Solar wind speed remains high, however, and G1 (Minor) storm episodes are still possible,” it said.
The most extreme geomagnetic storms are ranked as G5 storms by the National Oceanic and Atmospheric Administration. Space.com notes that on Halloween 2003 a powerful geomagnetic storm forced astronauts to seek shelter on the International Space Station because of potentially dangerous radiation levels, while also stressing power grids on Earth.
So far no damage from the St. Patrick ’s Day solar storm has been reported. Two blasts of magnetic plasma left the sun on Sunday, combined and arrived on Earth about 15 hours earlier and much stronger than expected, said Thomas Berger, director of the Space Weather Prediction Center, on Tuesday.
The storm ranked a 4, called severe, on the NOAA’s scale for geomagnetic effects. It was the strongest solar storm to blast Earth since the fall of 2013. It's been nearly a decade since a level 5 storm has hit Earth.
Forecasters figured it would come late Tuesday night into Wednesday morning; instead, it arrived just before 10 a.m. EDT. They had forecast it to be a level 1.
"It's significantly stronger than expected," Berger said, on Tuesday. Forecasters had predicted a glancing blow instead of dead-on hit. Another theory is that the combination of the two storms made it worse.
The storm had the potential to disrupt power grids but only temporarily, while also causing degradation of the global positioning system, affecting tracking maps and locators.
Often these types of storm come with bursts of radiation that can affect satellite operations, but this one has not, Berger said.
But the most noticeable effect is usually considered a positive. The Aurora Borealis or northern lights that usually can be viewed only in the far north dip south, so more people can enjoy the colorful sky show.
Forecasters said early Tuesday, before sunrise, auroras were already seen in the northern tier of the U.S., such as Washington state, North Dakota, South Dakota, Minnesota and Wisconsin.
The Associated Press contributed to this report.