Siren Warning System

Lightning flashing across a purple sky

The Village of River Grove has an outdoor warning system that uses a siren to alert citizens in the event of an emergency. Located at the River Grove fire station, this siren is designed to provide notice of impending danger. The following information explains the function, operation and procedures associated with the Village of River Grove's Outdoor Warning Siren System.

Warning System Activation

The system is designed to notify our community by using either Alert Warning or Attack Warning signals. The signals are standardized for outdoor warning devices by the Federal Emergency Management Agency (FEMA).

Alert Warning

An Alert Warning signal is a 3-to-5 minute steady siren. This signal is used during a severe weather emergency or funnel cloud sighting. The reporting area includes a ten-mile perimeter around the Village. The Alert Warning signal shall indicate to all persons to "immediately seek shelter, turn on your radio or television and listen for essential emergency information." Please note, severe weather watches are reports of weather conditions in which tornados could occur. The warning system is not activated for severe weather watches.

If the Alert Warning signal is activated:

  • Seek shelter immediately
  • Turn on your radio/TV for further information

Attack Warning

An Attack Warning signal is a 3-to-5 minute wavering siren. This signal means that an actual attack against the United States has been detected and that the Federal Emergency Broadcast System has been activated. According to federal government guidelines, "this signal will be used for no other purpose and will have no other meaning."

The use of indoor warning systems is essential too, as most residents and businesses will not hear the siren warning system unless they are outside. An indoor warning system includes commercial broadcast radio, television stations, cable television override systems, tone activated radio receivers and public address systems in public buildings.

If the Attack Warning signal is activated:

  • Stay indoors
  • Turn on your radio/TV for further information
  • Be prepared to move/evacuate if necessary


Once activated, the warning sirens will not be reactivated for the same incident. The warning sirens will only be reactivated for new, confirmed incidents.

All Clear

In keeping with established policies, the Village of River Grove will not issue the all-clear for any Alert or Attack signals. Please monitor commercial radio and television for further information.

Siren Testing

It is important that the Village warning system be tested on a regular schedule to ensure proper operation and to assist in educating the public to recognize the different warning signals. Testing occurs on the first Tuesday of each month at 10:00 am. Federal and state guidelines indicate that monthly warning system tests should occur in the following manner:

  • Alert Warning signal (steady siren) will sound for 1 minute
  • One minute of silence
  • Attack Warning signal (wavering siren) will sound for 1 minute

This testing procedure will establish a test pattern different from that used in an actual emergency when the signals are sounded for 3 to 5 minutes.

Be Prepared

Here's how you can prepare in advance of an emergency:

  • Have a battery-operated radio with spare batteries available
  • Siren testing takes place on the first Tuesday of each month at 10:00 AM. Learn how to distinguish each signal and what they mean.