National Geographic Online reports: "A powerful sun storm—associated with the second biggest solar flare of the current 11-year sun cycle—is now hitting Earth, so far with few consequences. But the potentially 'severe geomagnetic storm,' in NASA's words, could disrupt power grids, radio communications, and GPS as well as spark dazzling auroras."
The Washington Post echoes National Geographic Online's statement with its FAQ-type article about the phenomenon. First off, it explains what caused the event: "The (sun) storm is the result of strong flares released Sunday (March 4, U.S. Time) and Tuesday (March 6, U.S. Time) by a particularly 'potent sunspot.' The flares set off a major wave of plasma that reached the Earth on Tuesday (March 6, U.S. Time), assaulting the Earth’s magnetic field."
The Washington Post article then explained: "Certain things such as GPS satellites, electronic power grids and airline flight patterns are affected by side-effects of solar flares."
So, should people on the ground be worried? The Washington Post article stated, "Vastag and Samenow report that the Earth’s magnetic field will repel much of the radiation generated by the storms, so people on the ground should be safe."