A nuclear explosion outside the earth’s atmosphere produces an electromagnetic pulse (EMP). While there has been recent Hill, media, and fictional attention on the subject, EMPs have been a threat since the nuclear age. The grid does have certain vulnerabilities, and this post outlines what is (or isn't) at risk from EMP damage. While heavy power system assets such as switches and transformers are largely immune to immediate EMP interference, EMP-induced surge currents could overwhelm some protective systems. More importantly, the modern monitoring, communication, and control equipment are vulnerable to damage from an EMP. Such an attack could cripple power system operations. Detailed writeup follows.