"Emergency sirens" is a phrase that refers to loud, attention-grabbing sounds that are used in emergency situations to alert people about potential danger or a need for immediate action. Full definition
In Ocean City, N.J., emergency sirens sounded yesterday afternoon as police blocked access to the bridges that connect the resort community, which sits on a narrow barrier island, to the mainland. (scientificamerican.com)
The Alert Carolina system at the University of North Carolina at Chapel Hill likewise includes an outdoor emergency siren that serves as an alert for various security threats, including an «armed and dangerous person in the area.» (dukechronicle.com)
NRC has pledged to continue heightened oversight at Indian Point due to the leaks and Entergy's delays in installing new emergency sirens. (riverkeeper.org)