The northern lights are common near the Arctic Circle, but the Wasatch Back also gets an occasional glimpse of the lights, known as the aurora borealis.
National Oceanic and Atmospheric Administration space weather forecaster Shawn Dahl says the northern lights glow when solar materials that include charged particles and strong magnetic fields blast into space.
It’s the kind of solar storm called a coronal mass ejection — or CME — and what lit up local night skies.
“It's quite a complicated phenomena to make all that happen and all the things that have to come together to make it light up as much as it did earlier this week,” Dahl said on KPCW’s “Local News Hour,” Friday Nov. 14.
He says two such bursts reached Earth in recent days and at least one could arrive sometime Wednesday.
But, Dahl said Utah and much of North America were simply lucky to see the display for three reasons.
First is North America’s magnetic field dips further southward than in Europe or Asia, which Dahl said helps drive the lights further toward the equator. Second is the timing: the skies were dark because the sun is going down earlier and there wasn’t much moonlight. The third involves magnetism.
“If you think of a positive and positive magnet, they repel. If you think of a positive and negative magnet, they connect,” Dahl said. “Well, this storm connected, and it doesn't always do that.”
Dahl said on the space weather scale from one to five, the show was a G4, which was very rare. He said there was a point where the lights almost reached a G5, which is extremely rare and would have made the light show even more intense.
