lert) A U.S. system for notifying the public about emergencies, which include severe weather, evacuations and Amber Alerts. Government agencies send the alert to FEMA, which relays it to the cellular carriers that push the message to all subscribers' phones.
A 2018 Presidential Alert
Although alerts are typically targeted to affected locations, on September 20, 2018, an alert was sent nationwide to test the system. The four major carriers and more than 100 smaller carriers received the message.