Warning Sirens and Systems

Do you know...

...what those noisy sirens mean, anyway? Installed at the height of the Cold War to herald nuclear destruction, Sandwich's six outdoor warning sirens now (hopefully) have only one function: to announce the imminent arrival of severe weather to people engaged in outdoor activities. The Federal Emergency Management Agency defines siren tones as follows:

ATTACK WARNING Signal: An attack warning is a 3 to 5 minute wavering tone or siren, or a series of short blasts on horns or other devices. The ATTACK WARNING signal means that an actual attack or detected missile launch against the United States has been detected and that protective action should be taken immediately. The ATTACK WARNING shall be repeated as often as deemed necessary by local government authorities to obtain the required response by the population, including taking protective action related to the arrival of fallout." Per federal guidance, this signal will be used for no other purpose and will have no other meanings. ATTENTION or ALERT Warning Signal: An ATTENTION or ALERT Warning signal is a 3 to 5 minute steady signal from sirens, horns, or other devices. This signal may be used as authorized by local government officials to alert the public of peacetime emergencies. In addition to any other meaning or requirement for action as determined by local government officials, the 'ATTENTION' or 'ALERT' signal shall indicate to all persons....'Turn on your radio or television and listen for essential emergency information.'
From FEMA CPG 1-17 "Outdoor Warning Systems Guide"

Sandwich EMA does not control any other community's sirens but our own, nor do we plan to do so.

The sirens are under the control of the Police Department Dispatch Center, however, the decision to activate the sirens comes from SEMA. When severe weather is indicated, put our own spotters on alert. We monitor regional radar and lightning detection nets, and Amateur Radio and public safety frequencies of areas in front of the approaching weather. We are also in direct contact with the National Weather Service in Romeoville via Internet. This information is processed by the duty officer, and the threat is assessed.

When a trained spotter reports a tornado, funnel cloud, or other potentially hazardous weather within 5 miles of Sandwich, the duty officer orders siren activation. A SEMA officer or telecommunicator presses a console button, sending a preprogrammed radio code to the sirens. When the sirens sound, it is time to take your family to your predetermined shelter area in your home. DO NOT grab the camcorder and go outside, DO NOT call 911 to ask where the storm is. Get to your shelter area, turn on that battery powered radio, cover up, and get ready. Stay in your shelter until your radio tells you that the danger is passed. Per Illinois State Emergency Management Agency recommendations, Sandwich EMA does not sound an 'all clear' via sirens. 

The sirens are tested on the first Tuesday of each month, weather permitting. A test consists of either just the Alert tone, when activated by the Police Department Telecomm staff, or both tones when activated from either SEMA's primary or secondary warning points. These tests alternate by the month between the Police Department ant SEMA. Any other siren activation should be treated as a valid warning signal as defined above. For those of you on the west side of the city, please note that Lake Holiday has a pair of sirens under the control of the Somonauk Fire Department. Be sure of which siren you're hearing, as each agency has different activation criteria.

In addition, SEMA maintains a low-powered AM radio station at 530 kHz. At this time, the station rebroadcasts the NOAA Weather Radio audio from the NWR station located in Plano. In times of emergency, we can utilize the station to convey important information to the public. Finally, SEMA, along with other city agencies, can provide important information to the public via broadcast media and cable override.

These systems are an integral part of your weather awareness program, along with your NOAA Weather Radio, and your own 'eyes to the sky'.

For more information on the radio frequencies and systems discussed here, drop us an e-mail.

Portions copyright 1998
by the author and 2016 Sandwich, Illinois
Emergency Management Agency.