DULUTH - Northern Minnesota was at the epicenter of a rare aurora borealis display Thursday night that was so explosive it made one amateur astronomer weep.
"You couldn't take your eyes off of it," said Bob King, a Duluth resident and author of several astronomy books, including "Night Sky with the Naked Eye." "It was like an arsonist was going around with gasoline and setting things aflame."
The northern lights show could be seen across the northern tier of the United States, with photos from longtime aurora chasers and new ones overtaking social media feeds. The lights were strongest in parts of the upper Midwest, such as northern Michigan, Wisconsin and Minnesota, but could be seen as far south as Iowa, King said.
In Duluth, the show began at twilight, about 8:15 p.m., much earlier than typical. King had been monitoring auroral maps and predictions and knew it could be a big display, he said, and indeed it was, lasting into the wee hours of the morning. He moved around to a couple of his favorite viewing spots north of Duluth, finally calling it quits at 2:30 a.m., though the lights were still strong.
The array filled the southern sky early on, covering the constellation of Orion, King said.
"It evolved into a coronal display where all the rays gathered together to point upwards and meet in these crazy shapes: spiders, snakes and eagles," King said. "Then the flickering began."
Rays stretched "taffy-like" and flashed in "hundreds" of variations, in the sort of display he's only seen a handful of times.
"Finally, I laid down on the ground and looked up," King said, and thought, "who am I, what is this? It was one of those moments. It just made me cry."
He never took his telescope out of the car, the lights from the aurora were so bright.
Duluth photographer and gallery owner Ryan Tischer headed up the North Shore to capture the aurora, the best display he's seen in two decades shooting them.
"You could even see it with the naked eye," he said, which isn't always possible. "It started off faint and then it just absolutely exploded overhead and on the horizon."
Like most photographers who shoot the lights, he was reluctant to share his viewing spot because hordes of cars mean headlights that can impede the show. As it was, he had to work around others who had the same idea.
Brian Murphy Slattum is administrator of the Facebook group "Upper Midwest Aurora Chasers." He warned members Thursday that it would be a "pants on" night, meaning a light show was all but guaranteed, so be ready to go.
"This was considered a major (solar) storm," said Murphy Slattum, an amateur space weather forecaster. "It might be in the top 50 geomagnetic storms of all time."
King expected another auroral display Friday night, but with a later start and not as expansive.
So, how to know when to get in the car and seek wide-open sky? The National Oceanic and Atmospheric Administration (NOAA) offers a three-day forecast of potential expected disturbances to Earth's magnetic field, caused by solar wind. If solar wind is moving rapidly, it can create geomagnetic storms that lead to northern lights displays.
NOAA also offers a free subscription service that sends forecasts and alerts.