Outdoor Warning Sirens


Hamilton County has a total of 75 outdoor warning sirens throughout the county.  Sirens are only intended to warn people who are outdoors and not intended to warn residents in their home.  The sirens are owned and maintained by the municipality where the siren is located.  Each municipality has an inter-local agreement with Hamilton County Emergency Management to sound the sirens during severe weather.  Each municipality also can sound the sirens.  There are multiple nodes that send information to the sirens allowing for redundancy in the system.  Hamilton County only owns one siren and it is located at White River Camp Grounds.

emergency siren

Outdoor Sirens

There are currently 75 outdoor warning sirens in Hamilton County:
Town of Arcadia - 1

  • Town of Atlanta - 1
  • The city of Carmel (Including Clay Township) - 21
  • Town of Cicero - 2
  • Indiana Academy - 1
  • The city of Fishers (Including Delaware and Fall Creek Townships) - 20
  • The city of Noblesville (Including Noblesville Township) - 19
  • Town of Sheridan - 1
  • The city of Westfield (Including Washington Township) - 8
  • White River Campground - 1 (owned/maintained by the Hamilton County Parks Department)

Sounding the Sirens

Hamilton County Emergency Management sounds the sirens when the National Weather Service issues a tornado warning or when a trained weather spotter or public safety personnel sees a funnel cloud or tornado.  Sirens are grouped geographically by the municipality and sounded together when the warning criteria are met.  For example, if a tornado warning by the National Weather Service includes a portion of Noblesville, all of the Noblesville sirens will be sounded.  The only time all sirens will be activated is if a tornado warning polygon included the entire county.  

Most of the outdoor warning sirens are capable of producing multiple tones (wail, steady, and fast wail); however, only the wail tone is used for severe weather.  We do not use an all-clear sound.  To know if the all-clear is given, listen to your NOAA Weather Radio for the warning to expire or listen to NOAA Weather Radio on the free Hamilton County Emergency Management, Indiana App.

Sirens could potentially be used to alert people of a shelter in place or evacuation order; however, this would be done at the direction of the siren owner.

History and Why Sirens

Civil Defense first installed sirens as air raid sirens to warn the public of a possible attack or nuclear war.  Civil Defense eventually transitioned to Emergency Management, taking an all-hazards approach.  Sirens began being used for tornado warnings.  As communities have expanded, so have the sirens.


Hamilton County Emergency Management tests all sirens on Fridays at 11:00 a.m., starting the Friday before the statewide tornado drill and ending last Friday in October.   The sirens are automatically sounded, and a report is sent to several individuals.  The information is reviewed for any issues.  If maintenance is required, the municipality will contact their service provider to fix the sirens.

The system continuously checks the sirens to ensure they are in working order.  For example, if the power goes out at a siren site, a message is sent to the system administrators stating the siren is on battery power.  The system checks for communications, battery status, and many other settings year-round to ensure the system is always ready for activation.

National Oceanic and Atmospheric Administration (NOAA) All-Hazards Weather Alert Radios

The best way to receive watches, warnings, and emergency messages is through an NOAA All-Hazards Weather Radio.  Weather radios are inexpensive and may include battery backup, and also works as an alarm clock.  We recommend every household in the county have a radio as a way to receive important information even if power and the internet are out.Weather Radio

Remember, outdoor Warning Sirens are intended to notify people who are outdoors that there is a severe weather situation occurring, and they should seek shelter immediately. These are not intended to warn you if you are inside your home.