Radio and television stations across the United States begin mandatory participation in the national Emergency Broadcast System, a nationwide civil defense alert network replacing the CONELRAD system of the 1950s. Much like CONELRAD, EBS tests and activations initially require the rapid shutdown and reactivation of transmitters, at least until that practice is abolished in favor of a two-tone warning sound in the 1970s. Though the switch from CONELRAD to EBS is sparked by the 1962 Cuban Missile Crisis, the EBS will later become more closely associated with severe weather warnings.
