Warning sirens can do more than alert residents of an approaching tornado. The sirens may warn citizens of more than just weather-related emergencies.
The wailing sound also can be used to alert people of such emergencies as hazardous material spills, other man-made disasters, or terrorist attacks.
The sirens tell people to seek shelter indoors and, as soon as possible, tune into a local media source - a radio or television station, weather radio or Internet-based sources such as advertiser-tribune.com.
That said, there are things the warning sirens don't do. They do not summon people to go outside and look for funnel clouds. And the sirens are not a prompt to dial 911 and ask what's going on; 911 should only be used to summon emergency help.
Remember, sirens mean seek shelter.