On Thursday, FEMA will perform a test of IPAWS: Integrated Public Alert and Warning System. It will send a message to all the phones in the United States to test the infrastructure of the warning system. The test will take place around 2:18 PM ET and will last half an hour. It is a huge deal that the federal government will take command of every cell phone tower in the country in order to reach everyone at once with a test emergency text message. While there is an opt out provision for some emergency alerts, this isn’t one of them. You cannot disable it.