History professor 
William R. Forstchen discussed the potential damage  rendered by an 
EMP (electromagnetic pulse) event, and what we can to do  prepare for the possibility. There are actually two kinds of potentials  for generating an EMP, military or solar, he explained. A nuclear  fission weapon, such as Iran or North Korea are currently developing,  that is detonated about 250 miles above the Earth's atmosphere would  trigger electrostatic discharge, striking the Earth's surface and  overloading the power grid and knocking it out, he detailed. The Soviets  conducted an EMP test in 1962, and a power plant 500 miles away from  the center of the detonation burst into flames, because of the EMP  overload that fed into the transmission lines, he cited.
Just a  few days ago, we were hit by the largest solar storm in five years, and  NASA & NOAA have predicted a significantly increased solar storm  cycle over the next 18 months, Forstchen noted. A large enough coronal  mass ejection (CME) from the sun could generate a global-wide EMP event,  particularly in the northern and southern latitudes. The "Carrington  Event" of 1859 blew out telegraph lines, and the "energy output was so  intense that railroad ties were bursting into flames," he said.  Forstchen advocates congressional action to protect America's grid, such  as put forth by Cong. Roscoe Bartlett.
Biography:
William  R. Forstchen is a Professor of History and Faculty Fellow at Montreat  College, in Montreat, North Carolina. He received his doctorate from  Purdue University with specializations in Military History, the American  Civil War and the History of Technology. His current book, One Second  After was cited on the floor of Congress and before the House Armed  Services Committee by Congressman Roscoe Bartlett (R.-MD), chair of the  House Committee tasked to evaluate EMP weapons, as a realistic portrayal  of the potential damage rendered by an EMP attack on the continental  United States.
Wikipedia
An electromagnetic pulse (commonly  abbreviated EMP) is a burst of electromagnetic radiation. The abrupt  pulse of electromagnetic radiation usually results from certain types of  high energy explosions, especially a nuclear explosion, or from a  suddenly fluctuating magnetic field. The resulting rapidly-changing  electric fields and magnetic fields may couple with  electrical/electronic systems to produce damaging current and voltage  surges.
In military terminology, a nuclear warhead detonated  hundreds of kilometers above the Earth's surface is known as a  high-altitude electromagnetic pulse (HEMP) device. Effects of a HEMP  device depend on a very large number of factors, including the altitude  of the detonation, energy yield, gamma ray output, interactions with the  Earth's magnetic field, and electromagnetic shielding of targets.
Preparedness  refers to the state of being prepared for specific or unpredictable  events or situations. Preparedness is an important quality in achieving  goals and in avoiding and mitigating negative outcomes. It is a major  phase of emergency management, and is particularly valued in areas of  competition such as sport and military science.
Methods of preparation include research, estimation, planning, resourcing, education, practicing and rehearsing.
Survivalism  is a movement of individuals or groups (called survivalists or  preppers) who are actively preparing for emergencies as well as possible  disruptions in social or political order, on scales ranging from local  to international. Survivalists often have emergency medical and  self-defence training, stockpile food and water, prepare for  self-sufficiency, and build structures that will help them survive or  "disappear" (e.g. a survival retreat or underground shelter).
Anticipated  disruptions include the following: Clusters of natural disasters,  patterns of apocalyptic planetary crises, or Earth Changes (tornadoes,  hurricanes, earthquakes, blizzards, solar storms, severe thunderstorms).  A disaster caused by the activities of humankind (chemical spills,  release of radioactive materials, nuclear or conventional war,  oppressive governments). The general collapse of society caused by the  shortage or unavailability of resources such as electricity, fuel, food,  or water. Financial disruption or economic collapse (caused by monetary  manipulation, hyperinflation, deflation, or depression). A global  pandemic. Widespread chaos or some other unexplained apocalyptic event