The U.S. Federal Emergency Management Agency and FCC will conduct the first ever nationwide test of the Emergency Alert System. The test will last for about 30 seconds and will look and sound similar to past system tests. The alert system allows the president, as well as state and local authorities, to broadcast warnings about disasters, severe weather and other emergencies. It’s a practice exercise to assess how well the system would perform its primary function: alerting the public about a national emergency, the FCC says.”]
Source: https://www.csoonline.com/article/2130045/us-agencies-to-test-emergency-alert-system.html