Nation What’s a solar flare? And how can a geomagnetic storm make auroras visible in the U.S.? October 12, 2021Asha C. Gilbert, USA TODAYComments Off on What’s a solar flare? And how can a geomagnetic storm make auroras visible in the U.S.? A quick look at how a solar flare can cause a geomagnetic storm on Earth, sometimes resulting in brilliant auroras, like the northern lights.