'Remarkable and unexpected,' colorful northern lights (aurora borealis) filled skies from Arizona to North Carolina

A brilliant aurora appeared Thursday night in Shenandoah National Park. (Photo by Peter Forister)

In a word, breathtaking. "As soon as the sun set Thursday, extreme weather photographer Peter Forister excitedly headed for the hills. Forecasts had suggested that recent storming on the surface of the sun could set off auroras — brilliant dancing streaks of light, also known as the northern lights — in the Lower 48 states," reports Kasha Patel of The Washington Post. "At around 11 p.m., the sky lit up with vibrant red and yellow streaks visible to the naked eye." Forister told Patel, "You just step back and jaw drop and just watch the show for a few minutes. It was really remarkable, like the kind of show that will make you stop and just catch your breath." Patel writes, "Yet the light show wasn’t in an aurora hot spot such as Canada, Iceland or even the northern tier of the United States. This was in Shenandoah National Park in Virginia, 75 miles southwest of D.C."

That show was no average sun storm. "On Thursday night, a 'severe' geomagnetic storm — rated a level four out of five by the National Oceanic and Atmospheric Administration — brought vibrant, bright auroras as far south as Arizona, California, Oklahoma, Iowa, New Mexico and North Carolina, according to reports on Twitter," Patel notes. "Some even reported seeing another newly discovered aurora-like phenomenon called STEVE, or Strong Thermal Emission Velocity Enhancement, which shows as bright streaks rather than the aurora's curtain effect. Bill Murtagh, program coordinator at NOAA's Space Weather Prediction Center, told Patel, "We were not expecting that level of storm by any means. A lot of variables come into play. … It's difficult to get people spun up for the aurora because so often things don't work out much more often than they do." Patel adds, "The last time a severe 'G4' level storm like this occurred was 2017."

How does this work? "Murtagh explained: Think of the coronal mass ejection as a magnet shot out from the sun. That magnet now interacts with the Earth's magnetic field," Patel reports. "Like two bar magnets, the fields connected in such a way that 'just opened things up.' Murtagh told Patel, "The [sun's] magnetic field coupled perfectly with Earth's magnetic field, and the consequence was severe storming and beautiful aurora extending down into the mid-latitudes."

It also involves something called a "puff." Patel reports, "NASA solar physicist Alex Young said 'a puff' appeared to come from the center of the sun and practically had a straight shot at Earth. . . . Those kinds of puffs are called stealth coronal mass ejections, which Young thinks kicked the geomagnetic activity up a notch. . . . Young said we're also in what some people loosely call 'aurora season.' Auroral activity tends to pick up around the equinoxes, one of which just passed on Monday."