The state of Hawaii adds an “attack warning” tone siren to its monthly “attention alert” tests for hurricanes, tsunamis and earthquakes.
This is how it sounds:
According to StarAdviser: ‘At 11:45 a.m. Dec. 1, during regular siren tests on the first business day of each month, 50 seconds of the steady-tone alert will be followed by a pause and then 50 seconds of the attack warning tone, said Hawaii Emergency Management Agency Executive Officer Toby Clairmont.‘
The siren was re-introduced by officials due to North Korean nuclear threat. Last time Hawaii residents heard the attack warning siren test was around 1980 during the Cold War.
If used as an actual warning, the attack warning siren would signal the need to immediately seek shelter.