"The sun is bombarding Earth with radiation from the biggest solar storm in more than six years with more to come from the fast-moving eruption."
"The solar flare occurred at about 11 p.m. EST Sunday and will hit Earth with three different effects at three different times. The biggest issue is radiation, according to the National Oceanic and Atmospheric Administration's Space Weather Prediction Center in Colorado.
The radiation is mostly a concern for satellite disruptions and astronauts in space. It can cause communication problems for polar-traveling airplanes, said space weather center physicist Doug Biesecker.
Radiation from Sunday's flare arrived at Earth an hour later and will likely continue through Wednesday. Levels are considered strong but other storms have been more severe. There are two higher levels of radiation on NOAA's storm scale — severe and extreme — Biesecker said. Still, this storm is the strongest for radiation since May 2005."
Seth Borenstein reports for the Associated Press January 24, 2012.