The challenge of quickly notifying a large number or group of people located in different areas has not changed over the years, but the methods used for mass notification certainly have evolved over time. Let's look at the maturation of mass notification methods and systems as they have changed throughout history.
Word of Mouth: Church Bells and Town Criers
Church Bells, Town Criers, and men on horseback would alert townspeople of important news. On April 18, 1775, Paul Revere and others spread the word through signal lanterns in churches throughout the Boston area that the "British were coming" — an early form of mass notification deployed to warn settlers of impending danger.
Newspapers, Sirens, and Phone Trees
Newspapers provided a reliable, if not timely, way to inform large areas about important news. In the early 1900s, sirens replaced bells for early warning systems, playing a prominent role in World War II air raids and later used for nuclear attack warnings and natural disaster alerts. Communities also implemented phone trees — pre-planned systems where designated individuals passed news along a chain until all members were notified.
Radio and Television
The 1930s Golden Age of Radio and the post-WWII television era brought mass communication to new heights. Both mediums would interrupt regular programming to notify audiences of critical news, forming the foundation for modern broadcast emergency systems.
CONELRAD and the Emergency Broadcast System
CONELRAD (1951) was implemented by the U.S. government to convey news of enemy attacks during the Cold War. In 1963, the Emergency Broadcast System (EBS) replaced CONELRAD, activating more than 20,000 times between 1976 and 1996 to broadcast civil emergency messages and severe weather warnings.
Reverse 911 and Amber Alerts
In 1993, Reverse 911 was developed, using telephone databases to deliver recorded emergency messages to specific geographic areas. Amber Alerts were established in 1996 to rapidly notify communities about missing or abducted children — named after Amber Hagerman, a 9-year-old abducted in Arlington, Texas.
Emergency Alert System and Wireless Emergency Alerts
In 1997, the EBS became the Emergency Alert System (EAS), a national warning system designed to allow the president to address the country via all radio and television stations. In 2013, Wireless Emergency Alerts (WEA) were added, enabling participating wireless carriers to broadcast emergency notifications directly to subscribers' cell phones — including Presidential alerts, imminent threat alerts, and Amber Alerts.
With the maturation of mass notification, messages are conveyed through a multitude of channels. No longer does the general public rely on church bells or word of mouth — today mass notification alerts are sent using television, radio, landline telephones, digital signage, and cell phones.
