The sun has unleashed its most powerful solar flares in four years, sending a torrent of charged particles that could bring auroras as far south as Washington, D.C., scientists say.

Earth-bound flares — coronal mass ejections, in non-layman's terms — began erupting Sunday, with the biggest flare since December 2006 recorded on Tuesday, NASA's Solar Dynamics Observatory reports. Though such magnetic storms can affect communications and power grids (shortwave disruptions were reported today in southern China), no serious problems are anticipated, because the flare isn't expected to hit Earth head on.

Here's time-lapse video of the big blast.

The U.S. Space Weather Prediction Center forecasts a 30% chance of auroras as far south as the nation's capital, though the full moon tonight will make the reddish light quite difficult to see, National Geographic says. But skywatchers in the United Kingdom may see the more spectacular aurora borealis, the Northern Lights, over the next few nights.