This article is from 2011, just about a year ago, but still relevant... and scary.
What If the Biggest Solar Storm on Record Happened Today?
In 1859 "...geomagnetic disturbances were strong enough that U.S. telegraph operators reported sparks leaping from their equipment—some bad enough to set fires...if something similar happened today, the world's high-tech infrastructure could grind to a halt... The eastern half of the U.S. is particularly vulnerable, because the
power infrastructure is highly interconnected, so failures could
easily cascade like chains of dominoes. Imagine large cities without power for a week, a month, or a year..."
I ask again, "will you be prepared when the digital world dies?"