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Headlines Warning Sirens
Warning sirens are used in Chatham County to notify people about ALL hazards (such as hazardous materials, fires, explosions, tornadoes) that would require the public to act to ensure their safety. Keep reading to learn more about the siren program, or
download this Siren Program Guide.Description of the Chatham County Siren Program
There are 31 sirens currently located throughout Chatham County. The sirens have an effective range of 2 miles in diameter. At 100 feet, the sirens are heard at 129 decibels (the equivalent sound level of a jet engine taking off). At 1 mile, they're heard at 70 decibels (the equivalent sound level of a normal conversation).
Able to conduct a weekly, silent test to verify the status of each individual siren. (If a speaker is out, low DC power, no AC power to the siren, rotor failure, etc, we will know about it and can fix it immediately.)
One of Chatham Emergency Management Agency's (CEMA's) goals is to install more sirens within the next five years to cover 95% of the County.
What the Public Needs to Know if They Hear a Siren:
Each siren makes the sound of one long wail which is distinctly different from the short, repetitive wails of fire engine truck sirens or police car sirens.
The Sirens are tested the first Wednesday of every month at 12:00 noon only if it is sunny outside. This testing program is designed to maintain a reliable warning system and to meet State and Federal testing guidelines. In the event of bad weather, the test will be cancelled to avoid confusion.
The Sirens are used to notify people about ALL hazards (such as hazardous materials, fires, explosions, tornadoes) that would require the public to act to ensure their safety. The Chatham County Siren Program was designed to alert individuals who are OUTSIDE to take refuge immediately inside of a sturdy building. Once inside, monitor emergency advisories by listening to NOAA weather radios (strongly recommended), commercial radio or televised newscasts.
Specifics about Tornadoes What is a tornado?
A tornado is a rapidly rotating column of air usually descending from a large thunderstorm. Tornadoes are the most violent storms on the surface of the Earth. They have the highest wind speeds of any weather phenomenon. The strongest tornadoes are more intense than the biggest hurricanes, but they affect smaller areas.
U.S. tornadoes typically move from southwest to northeast at speeds up to 62 mph, with rotating wind speeds sometimes in excess of 310 mph. Tornadoes generally occur near the trailing edge of a thunderstorm and are formed by three fast-moving air masses, all going different directions that impart shears in a thundercloud creating a rotation. Additional energy is received via lightning and latent heat released by rainfall. Tornadoes can occur at any time of the year but are most common in late spring and early summer.
Wind damage from tornadoes is gauged by the Enhanced Fujita Scale:
EF-0: 65-85 mph
EF-1: 86-110 mph
EF-2: 111-135 mph
EF-3: 136-165 mph
EF-4: 166-200 mph
EF-5: over 200 mph
Tornadoes and Chatham County A tornado watch is issued by the Charleston National Weather Service when conditions are right for tornado development. There is still time to relocate to a safe area. During a tornado watch, listen to a radio or television for weather reports, and be prepared to take shelter if you hear a tornado warning.
A tornado warning is issued by the Charleston National Weather Service when a tornado has been sighted or appears on weather radar. If you are outside and hear a Siren, get inside of a sturdy building immediately and monitor your weather radio, commercial radio and television for advisories and updates.
If you are in a mobile home when a tornado warning is issued, get out and go to the closest sturdy building and monitor severe weather advisories by listening to weather radios, commercial radio or televised newscasts.
Watch for the danger signs of a tornado which are dark, often greenish skies; large hail; a dark, low-lying cloud; or a loud roar, similar to a freight train.
If you see approaching storms or any of the danger signs, be prepared to take shelter immediately in the lowest floor of a building or in an interior room or hallway. Get under a sturdy piece of furniture and put as many walls as possible between you and the outside. Stay away from windows.
If you are outside or in a car with no buildings in site, get out of your car and lie flat in a nearby ditch or depression and cover your head with your hands. DO NOT seek shelter underneath a highway overpass!
For additional information on the siren program and emergency planning, contact CEMA at (912) 201-4500.
