Outdoor Warning Sirens


Hamilton County has a total of 76 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 76 outdoor warning sirens in Hamilton County:
  • Town of Arcadia - 1
  • Town of Atlanta - 1
  • City of Carmel (Including Clay Township) - 21
  • Town of Cicero - 2
  • Indiana Academy - 1
  • City of Fishers (Including Delaware and Fall Creek Townships) - 20
  • City of Noblesville (Including Noblesville Township) - 20
  • Town of Sheridan - 1
  • 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 a tornado warning is issued by the National Weather Service or when a funnel cloud or tornado is sighted by a trained weather spotter or public safety.  Sirens are grouped by municipality and the sirens for the municipality are sounded when a warning polygon incorporates the municipality.  The only time Hamilton County Emergency Management activates all sirens is if a tornado warning polygon included the entire county.  There is only the activation tone of the sirens; we do not use an all clear sound.

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

History and Why Sirens

Sirens were first installed by Civil Defense as air raid sirens to warn the public of a possible attach or nuclear war.  Civil Defense eventually transitioned to Emergency Management when sirens were then used for tornado warning.  As communities have expanded, so have the sirens.


Hamilton County Emergency Management tests all sirens on Fridays at 11:00 a.m.  The sirens are automatically sounded and a report is sent to several individuals.  The report 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.  The system checks for communications, battery status, and many other settings.

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

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.

Weather Radios

Hamilton County Emergency Management recommends the purchase of a NOAA weather radio to warn you of severe weather, day or night, when you are inside your home. You will want to purchase one with the Specific Area Message Encoding (SAME) feature, which means the receiver is capable of turning itself on from a silent mode when the signal for your area is sent out. These radios can be programmed for specific areas so you do not receive alerts from areas far away. Read a list of Indiana County SAME Codes by County.