Don't worry if you missed the Northern Lights, they could be back soon

During the past few nights, not long after the sun fell below the horizon, some Californians had a chance to see the aurora borealis, usually only visible a few thousand miles to the north.

What you could see in L.A.

While it was quite visible up in the northern part of the state, the show was a bit more muted here in L.A.

The role a big eruption on the sun played

The exceptional event was the result of a massive eruption on the sun last Friday, according to Bill Murtagh, program coordinator at NOAA’s Space Weather Prediction Center.

The coronal mass ejection shot a billion tons of plasma with an embedded magnetic field straight towards Earth. Traveling at roughly 2 million miles per hour, it took a few days for it to traverse 93 million miles before reaching us.

When the blob of ionized gas arrived, it began to react with Earth’s magnetic field. The particles came flowing into the polar regions, ultimately interacting with elements like oxygen and nitrogen in the atmosphere, triggering a wonderful light show.

The bigger the disturbance in Earth’s magnetic field, the farther south the aurora is visible. This storm was rated G4 on the Prediction Center’s five-level geomagnetic storm scale.

Why solar activity waxes and wanes

Every 11 years, the sun’s poles flip, and during that time solar activity waxes and wanes. Currently, we’re approaching solar maximum, meaning there are more opportunities for strong eruptions, as activity peaks in the coming years.

“We’ll be seeing a handful to a dozen of these storms pretty much every year for the next three or four years,” said Murtagh.

These storms can impact important infrastructure like power grids and disrupt the accuracy of GPS. The Space Weather Prediction Center monitors the sun 24/7 and works to help others anticipate those impacts.

“G5’s the one that scares us,” said Murtagh. “From an impact perspective, we had a G5 in March of ‘89 that brought the electric power grid down across the province of Quebec and Montreal … power grid issues were reported across the continent.”

How not to miss your next chance to see the aurora in California

Although scientists can’t perfectly predict exactly how far south the aurora borealis will be visible, any strong G4 level storm raises the odds you’ll spot it in the skies above California. A G5 could mean it's visible all the way down in Central America.

Sign up for NOAA’s geomagnetic storm alerts over here. And if you get a G4 alert, increase your odds of getting to see the aurora first hand by heading north to the darkest spot you can find.