Hawaii is preparing for the possibility of a nuclear strike from North Korea days after the nation tested its most powerful weapon to date.
The state on Friday will start testing a siren intended to warn people of an impending nuclear attack. It will be incorporated into monthly testing of the warning system for natural disasters.
The attack warning will produce a different tone than the long, steady siren for tsunamis and other events. It'll include a wailing sound in the middle to distinguish it.
The test comes the same week that North Korea fired a powerful nuclear-capable intercontinental ballistic missile that some observers believe could reach the U.S. mainland.
Hawaii is the closest state to North Korea, and its large military presence could make it more of a target.