For much of the U.S. public, an attack involving the detonation of a nuclear weapon conjures up an image of a device being detonated within or directly overhead of a city or other target, resulting in the familiar mushroom cloud. But according to one national security expert, the greater threat is if an adversary detonated a nuclear device far above the U.S., triggering an electromagnetic pulse (EMP) that could have devastating effects on critical infrastructure. That is because the electrostatic discharge from a nuclear detonation, even one involving a relatively low-yield warhead, could travel hundreds of miles and destroy electric wiring and circuitry. The electric grid would be among the hardest hit of all U.S. critical infrastructure. One study on the issue estimated a moderate to high-yield EMP strike could shut down 500 primary generating systems from the central to the eastern U.S. and that 80 percent of the entire grid would still be dark and offline five years later. Not only would water and wastewater utilities likely experience the direct effects of an EMP strike, but they would also have to contend with power outages beyond anything seen or planned for before. Recommendations for addressing the vulnerabilities to this kind of attack include hardening electrical distribution systems and stockpiling key electrical components to more expeditiously restore critical functions. Read the article at Homeland Security Today.