Strong solar storm could produce northern lights in U.S.

An unusually strong solar storm hitting Earth could produce northern lights in the United States this weekend and potentially disrupt power and communications.

The National Oceanic and Atmospheric Administration (NOAA) issued a rare severe geomagnetic storm warning 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.

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

The storm could produce northern lights as far south in the U.S. as Alabama and Northern California, according to NOAA. But it was hard to predict and experts stressed it would not be the dramatic curtains of color normally associated with the northern lights, but more like splashes of greenish hues.

Experts said the best aurora views may come from phone cameras, which are better at capturing light than the naked eye.

The most intense solar storm in recorded history, in 1859, prompted auroras in central America and possibly even Hawaii.

This storm – ranked 4 on a scale of 1 to 5 – poses a risk for high-voltage transmission lines for power grids, but not the electrical lines ordinarily found in people's homes. Satellites could also be affected, which in turn could disrupt navigation and communication services here on Earth.

An extreme geomagnetic storm in 2003, for example, took out power in Sweden and damaged power transformers in South Africa.

Even when the storm is over, signals between GPS satellites and ground receivers could be scrambled or lost, according to NOAA. But there are so many navigation satellites that any outages should not last long.

The sun has produced strong solar flares since Wednesday, resulting in at least seven outbursts of plasma. Each eruption – known as a coronal mass ejection – can contain billions of tons of plasma and magnetic field from the sun's outer atmosphere, or corona.

The flares seem to be associated with a sunspot that is 16 times the diameter of Earth, according to NOAA. It's all part of the solar activity that's ramping up as the sun approaches the peak of its 11-year cycle.

Increased radiation also could threaten some of NASA's science satellites. Extremely sensitive instruments will be turned off, if necessary, to avoid damage.

Several sun-focused spacecrafts are monitoring all the action.

(Cover: Northern lights illuminate the sky in Anchorage, Alaska, the U.S., April 16, 2024. /CFP)