On Wednesday October 3rd, 2018 at precisely 2:19pm ET, your cellphone will beep and your radio will say “This is a test, it is only a test…” as the Federal Emergency Management Agency (FEMA) conducts a nationwide test of the Emergency Alert System (EAS) and Wireless Emergency Alert (WEA) system. The system allows FEMA, the White House, and other top-level federal agencies to quickly warn the public in the event of a national-level emergency.

Dating back to the 1990’s, when it was still called the Emergency Broadcast System, and even 1951, when it was called CONELRAD for “Control of Electromagnetic Radiation”, the EAS system was designed for radio, TV and cable systems to quickly warn of incoming ICBM nuclear missiles from the old Soviet Union during the Cold War. In modern times, it’s more used for severe weather events, or local emergencies like chemical spills or nuclear power plant problems. But starting a few years ago FEMA started testing it nationally once a year to make sure it can, if needed, fulfill its original purpose.

WEA is newer and designed for cellphones. It looks similar to a text message although the technology behind it is different. And it can be precisely geo-targeted to send warnings quickly to a specific population, like during the recent wildfires in California.  While highly useful, it’s had some high-profile gaffes in recent months.

It’s possible to turn WEA alerts off on your phone if they’re sent by state or local authorities, but you can’t turn off the national alerts. This has led to some politicizing of the system since our current President has high unfavorability ratings and is known to communicate through tweeting, another text-like system. Fortunately, there are several operations and legal reasons why President Trump cannot use WEA to simply tweet out messages.