Hi. Different places have sirens for different reasons, often for some sort of weather-related emergency, like tornados or earthquakes. In addition to emitting an actual siren sound, they can be used as a public address system in times of emergency. They used to ring out here in San Francisco on a weekly basis as a test. Here's some information on them:
Why do you have sirens? Sorry, I'm in Australia and don't know what this means.
Hi. Different places have sirens for different reasons, often for some sort of weather-related emergency, like tornados or earthquakes. In addition to emitting an actual siren sound, they can be used as a public address system in times of emergency. They used to ring out here in San Francisco on a weekly basis as a test. Here's some information on them:
https://abc7news.com/san-francisco-sirens-emergency-911-department-of-management/13664811/
Here's general information from the National Weather Service:
https://www.weather.gov/dvn/sirenFAQ