Scientists: 'Extreme' Solar Storm Heading to Earth

Scientists say an extreme solar flare is blasting its way to Earth and could mess up some power grids, satellites and radio transmissions.

Forecasters at the Space Weather Prediction Center don't yet know when Wednesday's solar storm will arrive here and which part of the planet will be facing the sun and bear the brunt of the effects. It could be as early as Thursday morning to a few days.

Prediction Center director Tom Berger said scientists will have a better idea after they get more satellite data.

The flare is considered extreme on forecasters' scale, but just barely. Flares like this cause geomagnetic storms which can knock some power grids offline temporarily. They also can damage satellites and disrupt radio transmissions. But they expand the colorful northern lights.