Civil Defense Sirens of O'ahu

All outdoor warning sirens in Hawai'i are tested on the first business day of each month at 11:45AM. 

• During this test, all sirens will sound a steady "ALERT" tone for 1 minute. The steady ALERT tone is used to notify the public of any all-hazard emergency, including natural disasters.

• In the event of a national emergency or enemy attack, the wailing "ATTACK" tone will be used to notify the public. The wailing ATTACK warning signal is strictly reserved for national emergencies, and this signal is not normally sounded during regular monthly testing.

•  O'ahu is home to multiple military installations, each base/installation has its own siren system. These siren systems are simultaneously tested in tandem with the HI-EMA statewide siren system every month. Military sirens will also sound in tandem with HI-EMA sirens during a real emergency.

    When you hear the ALERT signal...

• Seek information from official media sources.

• Anticipate limited communication (overloaded phone lines, ect).

• Do NOT make unnecessary phone calls, leave the phone lines open for emergency services.

When you hear the ATTACK signal...

• Take cover immediately; seek shelter underground, or in a solid concrete structure at ground level.

• Seek shelter in a room with no windows if underground or concrete shelter is unavailable. 

• Seek further information from official media sources.

• Do not leave your place of shelter unless directed to do so by officials.