Emergency alerts and warnings are an element of emergency plans designed to provide information that members of the public can use to protect themselves. Whatever the event, the general goal of emergency alerting is similar: successfully transmit information to the potentially affected population, have that message spread or diffuse to the people who need it, and do so far enough before the incident occurs that they can act accordingly (Sorensen, 2000).
Changes in technology and the way people consume media raised concerns that legacy alert systems were no longer sufficient to achieve the goals of alerting (U.S. Government Accountability Office, 2007). Mobile devices are the entry point for much of current media consumption and they have moved people away from traditional channels that could be used to transmit emergency alerts. Because these mobile devices are always at least somewhat location aware, they can provide a way to transmit alert information relevant to the position where a person is at the time the emergency is occurring, rather than to a home address or other less precise location. To take advantage of this potential, the Wireless Emergency Alerts (WEA) system was implemented in 2012 to deliver short (up to 90 text characters) emergency messages to individual mobile devices in a designated warning area (Federal Communications Commission, 2014). WEA is designed to be a new addition to the toolbox for emergency alerting in the United States — not to replace other channels for transmitting information to the public (Federal Emergency Management Agency, 2015).