Emergency notification systems were first introduced in the United States during the 1950s under the auspices of civil defense in order to provide a means of quickly disseminating information of concern in times of national or local emergency, such as severe weather, to the population of the area most directly impacted by the event. In addition to the federal Emergency Alert System, there are now a variety of local systems in place for communities to be rapidly informed of imminent danger. Closed emergency notification systems have since been created for even smaller audiences such as businesses or college campuses. This entry discusses the history of emergency notification systems in the United States and some of the systems in place there today.

While emergency alerts have been ...