A catastrophic, prolonged failure of the electrical grid—the sort of event whose effects are  depicted in National Geographic Channel’s upcoming American Blackout, which premieres Sunday—may seem like just apocalyptic science fiction to some viewers.  Unfortunately, though, the possibility of such a breakdown is all too real.  (See related interactive: “Survive the Blackout.”)

Government and utility industry officials are so concerned, in fact, that in November, they will stage a massive emergency drill, called GridEx II,  that will involve thousands of utility workers, business executives, National Guard officers, FBI antiterrorism experts and government officials from the U.S., Canada and Mexico.  They’ll practice responding to a simulated failure of large parts of the electrical system across North America. (See related