Don't worry: The government.
On Wednesday, the Integrated Public Alert and Warning System sent a test message to everyone using a cellphone in the US that runs on a network operated by a carrier participating in the . You'd know you got the message if the header read "Presidential Alert."
The content of the message also made it clear that the message is only a drill. It'll read: "THIS IS A TEST of the National Wireless Emergency Alert System. No action is needed."
If you've ever received an Amber Alert on your phone, the WEA test probably looked similar. That's because both types of messages are sent through the same Federal Emergency Management Agency system.
The WEA, launched in 2012, can be traced back to the 2006 Warning, Alert, and Response Network Act passed by Congress to fund a new emergency alert system called for by President George W. Bush. The moves came after criticism of the federal government's handling of Hurricane Katrina in 2005. This week's alert marks the first time the system has been tested nationwide.
While Wednesday's alert was only a test, an actual presidential alert would mark a significant national crisis.
"When those messages appear on mobile devices, people should take those extremely seriously," Antwane Johnson, director of the IPAWS system, told CBS News. "It has some direct impact on either life or safety."
How FEMA's emergency test works
The test message was sent out at 11:18 a.m. PT/2:18 p.m. ET on Wednesday, though FEMA said it might take a few minutes for the test to make it to all phones. Your phone might have alerted you that the test message arrived in a slightly different manner than normal text notifications.
"WEA includes a special tone (some describe it as quite loud) and a vibration, both repeated twice," according to a description on the FEMA website.
Most newer wireless phones are WEA-compatible, but you can check your phone's packaging or instructions to see if it is WEA-capable. WEA may also be referred to as "government alerts" or "emergency alerts." All the major national wireless carriers and most smaller service providers participate in the WEA program.
Of course, to receive the alert, your phone had to be turned on and connected to a cell tower that allows you to connect to your participating carrier.
While most WEA-enabled phones have a setting to turn off Amber Alerts and emergency alerts sent through the system, a Presidential Alert can't be blocked and should make it through on any compatible phone and network.
The WEA test was to be followed by a nationwide test of the Emergency Alert System, which is a similar message that will be played over broadcast radio and television stations, at 11:20 a.m. PT/2:20 p.m. ET.
Both tests werebut were postponed until Oct. 3 because of Hurricane Florence.
Originally published Oct. 2 at 1:56 p.m. PT.
Updated Oct. 3 at 5:59 a.m. PT: Added comment from FEMA's Antwane Johnson. Updated Oct. 3 at 11:22 a.m. PT: To reflect what just occurred.
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