District 7 TENS City of Clarksville Outdoor Siren Deployment
When disaster strikes, you may have only a short time to make what might be a life or death decision.
Even though it is rare, catastrophic events such as tornadoes or major chemical releases do occur. We can not predict exactly where or when they will occur, but we can take precautions to minimize the danger.
One of the most important things you can do is to be aware that a danger is present. Most of the injuries and deaths happen to people who are unaware or uninformed. For this reason, it is crucial that you understand the warning system.
For your convenience, this page has been broken down into the following sections:
- The Montgomery County Warning System
- Severe Weather Watches and Warnings
- Montgomery County Warning System Choices... You Decide
- Outdoor Sirens
- TENS
- NOAA Weather Radio
- Emergency Alert System
- Broadcast Television and Radio
- Internet
- Warning System Recommendations
- Contact Emergency Management for More Information
The Montgomery County warning system is much more than a system of outdoor sirens. The sirens are important, but they are just one component of a much larger system. There is a great deal of communication and coordination taking place behind the scenes before the sirens are ever sounded. Montgomery County's ability to provide warnings is a result of partnerships with the National Weather Service, local emergency response agencies, and major industries. It is also the result of dedicated Emergency Management and 911 Center staff as well as trained volunteer storm spotters and Ham Radio operators. These groups all work together to make up an integrated system of hazard detection, consequence prediction, and warning dissemination. These all are vital components of our warning system.
Montgomery County takes an "all-hazards" approach to public warning. This means that we use the same decision-making structure and alerting methods, regardless of the threat. Severe weather is far and away our most common threat, but it is not the only one we face. A major air-borne hazardous material release, for example, could cause a significant threat to public safety. An incident of this type may necessitate activation of any one of a number of components of the system, including outdoor sirens.
Typically, the National Weather Service is responsible for issuing all severe weather alerts. The National Weather Service, when issuing severe weather alerts, uses the terms "Watch" and "Warning." Knowing the difference between a "Watch" and a "Warning" is very important.
When conditions are favorable for severe weather to develop, the National Weather Service will issue a "Watch." When severe weather watches are issued, you should be alert for changes in the weather and be prepared to act quickly.
National Weather Service meteorologists use information from weather radar as well as a network of trained spotters to issue severe weather warnings. A "Warning" means that severe weather is actually occurring or is imminent. For example, a Tornado Warning means that the National Weather Service's Doppler radar is detecting wind circulation that could produce a tornado. Tornado Warnings are also issued if trained spotters have actually sighted a tornado or specific indicators of a tornado. You should take immediate steps to protect yourself when a "Warning" of any type is issued.
- Visit the National Weather Service for more information on watches and warnings.
- Visit the National Weather Service or Skywarn sites for more information on storm spotting.
When severe weather approaches, Montgomery County 911 Center and Emergency Management staff are in constant communication with storm spotters in the field and forecasters at the National Weather Service office in Nashville, TN. When issued, severe weather "Watches" and "Warnings" are broadcast over the NOAA Weather Radio station serving Montgomery County and passed to local radio and television stations. The information is also relayed to Montgomery County public safety officials who are responsible for activating local warning systems.
Clarksville - Montgomery County uses a combination of methods for alerting the public when disaster threatens. We recognize that no one application can provide warning to all citizens. As a result, we take a systematic approach, understanding the advantages and disadvantages of each component. Some of these alerting methods, such as outdoor sirens, are owned and operated by the City of Clarksville. Others, such as NOAA Weather Radio or local broadcast media are not controlled by the County, but cooperate in broadcasting warning information. Only you can decide which of these methods of receiving warning information works best for you and your family. Here is a summary of the available options.
The City of Clarksville owns and operates 12 outdoor sirens. The activation point of the sirens is in the Clarksville - Montgomery County E-911 Center. While tornado warnings are the most common cause for siren activation, the sirens should not be considered to be "tornado sirens." They are intended as an "all-hazards" alerting system and may be activated for any type of emergency situation. The sounding of the sirens does not necessarily mean that a Tornado Warning has been issued. In fact, it means only that an emergency event has occurred or is about to occur and you may need to take action to protect yourself. If you hear a siren, you should immediately seek additional information through local radio and television stations. In all cases, the siren warning signal is a three minute steady blast.
As the outdoor component of the alerting system, the sirens have a very important role. The sirens are the most effective means we have for alerting people who are outside. That being said, you should understand the benefits and limitations of the sirens before relying on them as your only source of warning.
First, sirens are designed to alert individuals who are outdoors. Sirens are not intended to alert people who are in cars, homes, or other buildings. Hearing sirens indoors may have been possible in the past, however, this should no longer be expected. Energy conservation practices and better insulation have effectively reduced the sound penetration into these areas. In addition many homes and businesses are air-conditioned. Very few buildings have open windows in the summer when it is hot and humid – the very time when severe weather is most likely to occur.
There are a number of factors that affect the range of the siren. First of these is sound output. Very simply, some sirens are designed to be louder than others. A louder siren will have a greater range.
Atmospheric conditions also affect siren range. Wind speed and direction, air stability, and relative humidity all affect the distance that the sound will travel. Your ability to hear the siren will change as these conditions change. It is very possible that from your location, in some cases you will be able to hear the siren, while in other cases, you won't.
Topography and background noise levels will also have an affect on your ability to hear the sirens. Hills, trees, and buildings can be barriers that block the sound. High background noise levels from highways or industrial areas can mask the sound of the siren. These conditions will effectively limit the warning range of the siren.
Sirens can also be very susceptible to disruptions in the electrical power supply. A majority of the sirens operate on power supplied by local utilities. Power failures, which are common during thunderstorms, can disable a siren. In addition, lightning striking a nearby power line can blow fuses in the siren itself. This will also disable the unit until the fuses can be replaced.
Even with these limitations, sirens can be a very affective source of warning, if you are outdoors and within range of the siren. You can see the visit the Clarksville Siren Page and select the .wav links to hear the sounds for specific conditions.
TENS ~ Telephone Emergency Notification System
Most residents know that they can call 9-1-1 to get police, fire, or emergency medical assistance. Now, the local E-911 center can use the TENS system to call residents and businesses with emergency information.
How does TENS work?
TENS allows the Local County E-911 Center to notify residents and businesses by telephone.
In the event of an emergency, an operator in the E-911 Center can identify the affected neighborhood or region of the District and record a message that describes the situation and recommends the protective actions residents should take. TENS will automatically call out to all listed telephone numbers within that geographic area and deliver the recorded message. If phone lines are busy, the system will attempt to redial those numbers a predetermined number of times to make contact. If an answering machine picks up the call, the emergency message will be left on the machine.
System Features
TENS has a number of distinct advantages over other components of the warning system.
- It can provide an initial warning as well as specific instructions to protect at-risk citizens. Both factors are necessary for an effective warning.
- TENS can target specific geographic locations, warning only those people who are directly at risk.
- The system uses existing devices (telephones) to alert citizens; there is no need for people to buy a specialized warning device.
- The system can deliver text messages to TTY/TDD devices. This feature has the potential to greatly enhance our ability to warn and protect citizens who are deaf or hard of hearing.
- System administrators can add telephone numbers to the database. This can be used to add unlisted telephone numbers, cell phone numbers as well as numbers associated to VoIP or pagers to the system.
System Limitations
As with any component of a warning system, the TENS system has limitations. These can be minimized with diligent administration of the system, but they will always exist to some degree:
- Cell phone numbers and other telephonic systems are not included in the telephone database. Cell phone numbers can be manually entered into the system either as part of a notification list or linked to a specific address. If linked to a specific address, the location of the cell phone number becomes essentially fixed to that location. This could lead to the situation of a cell phone being notified when the user is mobile and well out of the affected area. Or conversely, the situation where the user is mobile, is in the affected area, but is not notified because the fixed location of the number is in an unaffected area. Please consider this when registering cell phone information for addition to the database.
- The initial telephone number database contains only the telephone numbers listed in the White Pages. As a result, unless manually added to the database, TENS can not notify people with unlisted numbers or cell phones. To minimize this, The Homeland Security District 7 has provided a link for residents to enter contact information to be supplemented to the initial telephone database mentioned above. Register your phone number and address with us on our TENS signup form.
- TENS is very effective for making notifications within a well-defined geographic area. Due to the outgoing call capacity of the system, the system becomes less effective as the geographic area gets larger. For this reason, the District takes a systematic approach to warning, recognizing that no single application can provide warning to all citizens in all situations. The TENS system is an excellent enhancement to our system, but it does not replace any of the other components.
How will the system be used?
The system could be useful for many purposes however, Montgomery County is reserving it exclusively for emergency or disaster notifications. Possible uses include:
- Severe weather. Severe weather usually affects the entire County, or at least large areas of the County and is not typically an appropriate occasion for TENS activation. With one exception. The Department of Emergency Management is working with community groups to develop a list of County residents who are deaf or hard of hearing. The TTY/TDD capability of the system will be used to alert this list of Tornado Warnings issued for Montgomery County much in the same way the sirens are used to alert the hearing community. Register your TDD / TTY phone number and address with us on our TENS signup form.
- Hazardous materials release. An airborne hazardous materials release or potential for a release where there is a need for residents to evacuate or shelter-in-place.
- Community policing. Local police departments and the Montgomery County Sheriff's Department may use the system for a variety of community policing situations, such as missing children alerts or prisoner escape.
- Public health alerts. Montgomery County and the City of Clarksville public health departments may use the system to disseminate public health information such as boil water alerts or outbreak of infectious disease.
Add your telephone number to the database
The system was initially programmed only with those numbers published in the local White Page directories. Numbers not included in the initial programming were:
- Unlisted telephone numbers
- Residents or Businesses using Voice over IP Services
- Listed telephone numbers without a listed address
- Cell phone numbers
If you believe your telephone number was not included in the initial setup of the system, you may have your home or business included by filling out the form at the link below.
You can also register you information by calling Montgomery County Emergency Management at 931-648-5702 or by using our TENS signup form.
Information provided will not be released to third parties and will only be used for the purpose of emergency notifications in Montgomery County.
Citizens of Montgomery County can take advantage of the National Weather Service's 24-hour weather broadcast system. NOAA Weather Radio in Clarksville is broadcast on a frequency of 162.55 MHz. The National Weather Service broadcasts continuous weather information 24 hours per day. When conditions warrant, the Weather Service can interrupt programming to broadcast special weather statements and official severe weather "Watches" and "Warnings". In fact, local governments in Montgomery County rely heavily on information supplied by NOAA Weather Radio as a basis for mobilizing volunteer weather spotters and activating locally controlled components of the warning system.
We strongly encourage you to purchase a Weather Alert Radio so that you can receive warning information directly from the National Weather Service. The weather radio system is the most timely, most reliable, and most credible source of weather warning information currently available.
A weather alert radio is a small, desktop radio that works a little bit like a pager. The radio is normally muted and quiet, but can be activated by a special code transmitted by the National Weather Service. Once activated, most weather radios will sound an alerting tone to get your attention and even wake you up if you are sleeping. You will then receive a message describing the situation, directly from the source of the warning.
By special arrangement, NOAA Weather Radio in Montgomery County also broadcasts warnings for all types of hazards, both natural (such as severe weather) and man-made (such as an evacuation resulting from a toxic chemical release), making the weather radio a true, all-hazards warning device.
Weather radios are now available utilizing Specific Area Message Encoding or "SAME" technology. With SAME technology, the weather radio can be programmed to receive and display alerts and warnings that apply only to Montgomery County. With a SAME weather radio, you can avoid hearing warnings for areas that do not concern you. For more information on "SAME" follow the link above. For listings of Broadcaster Frequencies by State or Broadcaster Frequencies by County or Streaming Audio.
Most weather radios are equipped with battery backup, enabling you to receive warning information even if the power is out. In addition, individuals with hearing impairment can also get these warnings by connecting a weather radio to other types of attention-getting devices such as strobe lights, pagers, bed-shakers, personal computers, and text printers.
Weather alert radios are available at local electronics stores as well as from a large number of sources on the Internet. Depending on features, a weather radio can cost anywhere from $20.00 to $65.00.
The Emergency Alert System (EAS), adopted in 1997 is the successor to the old Emergency Broadcast System (EBS). The Emergency Alert System is composed of AM, FM, and television broadcast stations as well as cable television, operating in cooperation with local authorities to provide uniform and consistent information in an emergency. Participation in the local Emergency Alert System is voluntary however the following stations have agreed to broadcast local emergency alerts if requested. The list of Local and Nashville Stations can be found at The Society of Broadcast Engineers Chapter 103, follow the SBE-Ch103 link.
Other local broadcasters can pick up the message from any of these sources and rebroadcast it at their discretion. You can recognize an EAS message from the distinctive tone that begins each broadcast. The announcer will also identify the broadcast as an activation of the Emergency Alert System.
In an emergency, you should stay tuned to participating EAS stations to receive emergency warnings and situation updates. In addition, commercial receivers are available to receive EAS warnings directly. The complexity of these devices varies, with some being simple monitors of one EAS source to other units that can be set to monitor multiple sources. A number of EAS monitors are designed to be connected to external alerting devices, electronic message boards, and building public address systems. Most EAS monitors are relatively expensive and are designed for commercial use.
In addition to participating in the Emergency Alert System, broadcast television and radio stations are a vital component of our warning system. Local television and radio stations routinely broadcast official "Watches" and "Warnings" issued by the National Weather Service as well as forecasts and storm tracks developed by on-air meteorologists. Television, in particular, is an excellent source of emergency information since graphics such as radar displays and maps can be used to describe the event in detail.
Visit the websites of the local network affiliates to find out more about their severe weather warning programs:
- WKRN News Channel 2 (ABC)
- WSMV News Channel 4 (NBC)
- WTVF News Channel 5 (CBS)
- WZTV News Channel 17 (FOX)
Broadcast television and radio, while being an excellent source of information, have one major disadvantage as a means of receiving warning. Your radio or television has to be on and you have to be able to hear it or see it. If the TV or radio is not on or you are in another room, you will probably miss the warning. A normal TV or radio will not wake you up in the middle of the night to inform you that a tornado warning has been issued. For this reason, you should not rely on broadcast television or radio as your sole source of emergency warning.
The Internet offers a nearly inexhaustible source of information concerning storm warnings and severe weather forecasting. Please be aware that Internet sources of warning are not as dependable as the other systems referenced in this document. Information received from sources on the Internet is subject to delays and may not arrive soon enough to provide an adequate warning. In addition, your ability to receive information through the Internet requires the operation of numerous systems, some of which are completely beyond our control. The Internet should be considered as an additional source of information and should not be considered as the primary source of emergency warning for life-threatening events.
The private marketplace offers a wide variety of warning services, primarily weather-related on a fee-for-service basis.
The warning system can only be effective if you understand the benefits and limitations of the alerting methods available. There are a great deal of warning devices and methods available to you. We recommend that you take advantage of as many of them as possible. No one warning method is perfect and no one warning method can be guaranteed never to fail. By relying on one single method, such as the sounding of the sirens or the receiving information solely from broadcast meteorologists, you risk missing a warning if that system fails. By taking a systematic approach and getting information from more than one source, you are much more likely to receive the warning, even if there is a failure in one of the components.
We strongly recommend that you consider the following:
- Purchase a weather alert radio if you don't already have one.
- Subscribe to a wireless email alerting system if you carry an alphanumeric pager, digital cellular phone or personal digital assistant.
- Rely on the sirens only for outdoor warning.
- Turn to broadcast radio or television for details and follow-up information.
Montgomery County Emergency Management Agency
130 South First Street
Clarksville, Tennessee 37040
(931) 648-5702
Date Updated: