An EMP disaster from a high-altitude blast seems like science fiction: There is a silent flash high in the sky, and everything using electricity just … stops. Cars stop, power goes out, the Internet dies, satellites quit working, landline and mobile phone systems go out, and computers are destroyed. In a moment, we are back to 1850, as was dramatized in William Forstchen's 2009 novel One Second After.
While more people are becoming aware of the risk of an EMP attack, what almost nobody seems to realize is that magnetic storage media is also subject to data loss from electromagnetic phenomena. This includes hard drives, RAID storage arrays, thumb drives and even SD cards.
Even worse, most of what modern society has come to rely on — everything from retail transactions, bank records and business accounting records — is stored on magnetic media which may be quite literally wiped out in an instant.