A nationwide emergency alert test will take place Thursday.
Cellphone users within range of a cell tower and whose wireless carrier participates in the wireless emergency alert system will receive a broadcast lasting for about 30 minutes beginning at 11:30 a.m.
This will be the first nationwide test of the alert system coordinated by the federal government, which is only intended to be used during a catastrophic event or during a serious public safety issue facing the entire U.S.
Users will not be able to opt-out or disable the alert if they are within range of a cell tower. The message and tone is scheduled to occur before noon, though different models of phones may receive multiple messages or a message outside the scheduled time. The test message may also appear over radio and TV broadcasts.