Powerless : a novel / Tim Washburn.

"It strikes without warning. A massive geomagnetic solar storm that destroys every power grid in the northern hemisphere. North America is without lights, electricity, phones, and navigation systems. In one week, the human race is flung back to the Dark Ages. In Boulder, Colorado, weather technicians watch in horror as civilization collapses around them. Planes are falling out of the skies. Cars are dead. Pandemonium and terror grip the Northern Hemisphere. As nuclear reactors across North America face inevitable meltdowns, the U.S. President remains powerless in a heavily guarded White House. From London to Boston to Anchorage, there is no food, no water, no hope. It's every man for himself...and it will only get worse. Only one man--army veteran Zeke Marshall--is prepared to handle a nightmare like this. But when he tries to reunite with his family in Dallas--across a lawless terrain as deadly as any battlefield--he discovers there are worse things in life than war. And there are terrible and unthinkable things he'll have to do to survive" --