https://lidblog.com/vulnerable-to-an-emp-attack/
An electric grid is an interconnected network for electricity delivery from producers to consumers. Think of it as the internet but instead of moving information, it moves electricity across the country.
The U.S. electric grid is vulnerable to an Electromagnetic pulse (EMP) attack which will destroy the country.
Electromagnetic pulse (EMP) is an electromagnetic wave similar to radio waves, which results from secondary reactions occurring when the nuclear gamma radiation is absorbed in the air or ground. It differs from the usual radio waves in two important ways. First, it creates much higher electric field strengths. Whereas a radio signal might produce a thousandth of a volt or less in a receiving antenna, an EMP pulse might produce thousands of volts. Secondly, it is a single pulse of energy that disappears completely in a small fraction of a second. In this sense, it is rather similar to the electrical signal from lightning, but the rise in voltage is typically a hundred times faster. This means that most equipment designed to protect electrical facilities from lightning works too slowly to be effective against EMP.