The dry run will last for a minute, with the last test ending at 2:50PM, and will start from designated radio stations that form part of the National Public Warning System. From there, TV and radio stations will carry the broadcast. It's not expected to have any more disruption than monthly EAS warnings.

The test comes roughly a year after the FCC took steps to make emergency alerts more reliable, and to some extent reflects that mindset. While phone-based alerts can be very helpful if you're away from conventional broadcasts when an emergency strikes, they're not much use if a blackout or cyberattack prevents alerts from getting through in the first place.