Defining the Need


Assessment of Potential Disasters in Georgia

One must treat any assessment of potential disasters with extreme care. As recent history has shown, just because a particular disaster has a low probability of occurring, it does not mean that the disaster cannot occur. However, the assessment can be used as a guide towards effective planning, training and deployment of amateur radio resources.

This section lists the possible disasters and assesses how they could impact the community primarily on a statewide level.. The disasters in this section are presented in alphabetical order, and not in any order of precedence or probability of occurring. A model, which takes in to account disasters with the highest probability of occurrence, impact to the community and need for statewide resources is presented in the last section along with the 25 counties in Georgia assessed to be at highest risk for potential disasters.

The potential disasters discussed in this section include:

Airline Crash

The most recent major commercial airline disaster in Georgia occurred April 4, 1977 in Paulding County when a DC-9 lost power in a violent thunderstorm and crashed killing 68 people on board and eight on the ground. A commuter airline crash in Carroll County in 1985 left eight people dead and 13 seriously injured. In 2001, 21 people were killed in the crash of a Florida Air National Guard plane near Unadilla.

Even before September 11, 2001, airline crashes are almost always handled by local law enforcement and fire departments. The most likely impact to communications is call volume overload. Post-9/11, the potential for infrastructure damage and failure becomes more likely, as was seen in the collapse of the World Trade Center towers.

Airline crashes can occur in just about any area of the state, including remote, sparsely populated areas. On the other hand, although a large number of aircraft travel through Georgia on a daily basis, the probability of airline crashes remains very small.

Disease

The most significant threat from disease, as identified by GEMA, is from the West Nile Virus. While of concern to the general public, this disease threat has low risk of affecting the communications infrastructure.

A local outbreak of disease, whether from natural causes or from bio-terrorism could cause stress on a local area telecommunications infrastructure. For example, call volume overload could bring down the PBX of a hospital or county public health service. In some counties, ARES groups have trained with local medical services for such potential communications failures.

Drought

Drought is defined as "abnormal dry weather for a specific area that is sufficiently prolonged for the lack of water to cause serious hydrological imbalance." Although eased by 2002 spring and summer rains, Georgia has not seen a drought of the duration or magnitude ever, not even in the disastrous mid-1980s as that seen in the summers of 2001 and 2002. With the exception of the southeastern coastal areas, most of the state remains at moderate to severe drought levels (Palmer Drought Severity Indexes of -2.0 to -3.9), particularly in the northeast, central and southwest areas of the state.

Severe drought, per se, rarely causes impacts to communications infrastructures. However, wildfires are more common in drought-affected areas, which in turn could create situations where ARES support is required.

Earthquakes

Although earthquakes occur less frequently in the eastern United States than in California, historical records indicate that earthquakes and their associated seismic hazards exist in Georgia. Major damages have not taken place in this region since the last great earthquake over 100 years ago that killed 60 people and devastated the city of Charleston in 1886.

While large earthquakes are less frequent, some seismologists argue that earthquakes in the eastern United States can cause more damage than similar size earthquakes in the western United States. The greater population density in the eastern United States also increases the damage potential. Calculations of seismic hazard indicate that large distant earthquakes are likely to cause as much damage in Georgia, as earthquakes of any size with epicenters within the state.

The greatest threat for earthquakes is in the northwest part of the state, along the Southeastern Tennessee Seismic Zone. This area currently experiences one magnitude 4.0 earthquake about every 10 years (may rock objects off of shelves and cause some cracking of plaster).

In the event of a strong earthquake, damage to communications infrastructure and/or call volume overload can be expected. The damage may be limited in scope, near the epicenter, for example, or could be spread over a wide area. Although the risk of earthquake is moderate to low, the potential exists for widespread demands for ARES resources.

Extreme Heat

GEMA identifies extreme heat as a significant threat in Georgia. People are at risk for heat-related illnesses when their bodies' temperature control system is overloaded. The body normally cools down by sweating. However, sweating alone does nothing to cool the body unless the water is removed by evaporation. High relative humidity slows down evaporation. Under extreme heat and high humidity, the body temperature quickly spirals resulting in potential damage to the brain or other vital organs.

Several factors impact the body's ability to cool down during extremely hot weather. When the humidity is high, as typical in Georgia, sweat will not evaporate as quickly preventing the body from efficiently releasing heat.

In general, extreme heat would not be expected to damage communications infrastructure, unless coupled with some other threat (such as fire, severe storms, etc.). However, it is possible that under severe conditions, the American Red Cross or public health agencies may open public shelters, and ARES resources may be required to assist with these efforts.

Floods and Flash Floods

Floods are the most common and widespread of all natural disasters--except fire. Most communities in the United States can experience some kind of flooding after spring rains, heavy thunderstorms, or winter snow thaws. Floods can be slow, or fast rising but generally develop over a period of days.

Dam failures are potentially the worst flood events. A dam failure is usually the result of neglect, poor design, or structural damage caused by a major event such as an earthquake. When a dam fails, a gigantic quantity of water is suddenly let loose downstream, destroying anything in its path.

Flash floods usually result from intense storms dropping large amounts of rain within a brief period. Flash floods occur with little or no warning and can reach full peak in only a few minutes.

Flood waters can be extremely dangerous. The force of six inches of swiftly moving water can knock people off their feet. Flash flood waters move at very fast speeds and can roll boulders, tear out trees, destroy buildings, and obliterate bridges. Walls of water can reach heights of 10 to 20 feet and generally are accompanied by a deadly cargo of debris.

In the summer of 1994, Tropical Storm Alberto came ashore from the Gulf of Mexico through Alabama and the Florida peninsula. Over a span of two weeks, the storm-which never reached hurricane strength-dumped over two feet of rainfall as far north as the Atlanta metro area. The storm killed 34 people and caused more than $1 billion in damage. More than 40,000 people were evacuated and a presidential disaster area was declared in 55 Georgia counties. There was significant communications infrastructure damage, with telephone central offices and long-lines switching stations damaged by flood waters. The Georgia Section ARES was activated on a statewide basis for several days.

80% of Georgia's 159 counties have had presidential disaster declarations involving flooding, since 1990.

Hazardous Materials

Hazardous materials are chemical substances, which if released or misused can pose a threat to the environment or health. These chemicals are used in industry, agriculture, medicine, research, and consumer goods. Hazardous materials come in the form of explosives, flammable and combustible substances, poisons, and radioactive materials. These substances are most often released as a result of transportation accidents or because of chemical accidents in plants.

There are many chemical plants throughout the State of Georgia and hazardous materials are transported on Georgia's numerous state and interstate highways. A hazardous materials accident is usually a localized event, and is usually managed by local law enforcement. It is possible that the communications infrastructure could be damaged, especially if there is explosion or fire.

Georgia is also host to the Southern Company's Plant Hatch, in Baxely (Appling County) and Plant Vogle, in Augusta (Richmond County), both nuclear power plants, and the US Department of Energy's Savannah River Site-a nuclear weapons facility-is located very near Augusta in Aiken, South Carolina. In addition to the potential hazardous materials threats that these plants themselves could present, on occasion, nuclear material is transported on interstate and state highways, particularly to and from the Savannah River site.

Through funding from a Department of Justice Grant, GEMA is purchasing equipment to outfit 21 HazMat teams throughout the state. The equipment is being supplied with the understanding that these teams will agree to respond to incidents around the state where such equipment and expertise are not available.

Hurricanes

Georgia is impacted from tropical systems from both the Atlantic Ocean and Gulf of Mexico.

During a hurricane, wind gusts exceeding 74 mph and torrential rain can cause damage to Georgia's shoreline. The direct hit of a hurricane also can cause storm surge, a large dome of water more than 50 miles wide that sweeps across the coastline near the area where the eye of a hurricane makes landfall. Storm surge remains the greatest threat to human life, but effective evacuations have reduced the number of fatalities. Most deaths now are the result of inland flooding.

The six coastal counties at highest risk of evacuation because of storm surge are Bryan, Camden, Chatham, Glynn, Liberty and McIntosh.

Although hurricanes weaken as they move inland, the remnants of the storm can bring 6 to 12 inches or more of rain and hurricane-force winds (74 MPH or greater) as far north as the mountain regions of Georgia . Hurricanes also can produce damaging tornadoes. Major hurricanes were a fairly frequent occurrence in the 1800's, when Georgia was struck by five major hurricanes. The last Category 3 hurricane to make landfall in Georgia struck Savannah on August 31, 1898, killing an estimated 179 people. Although Georgia was spared the direct hit of a major hurricane in the 1900's, it experienced four direct hits from minor hurricanes:

  1. In 1911, a Category 2 hurricane hit Savannah, killing 17.
  2. In 1940, a Category 2 hurricane hit Savannah, killing 50.
  3. In 1947, a Category 2 hurricane hit Savannah, killing 1.

Hurricane David, a Category 2 hurricane, hit Savannah in 1979. No major damage was reported.

The explosion of population growth along the coast has complicated the evacuation and sheltering process. Millions of residents and tourists from Georgia and its neighboring states of Florida, North Carolina and South Carolina jam highways in search of safety and shelter when evacuation orders are issued.

Improved forecasting and warning capabilities have diminished hurricane-related deaths in the 20th century; however, damage to property has increased with the rapid growth along our coastal regions.

The threat of hurricane, and the resulting evacuation of populated coastal areas of Georgia is perhaps the most stressing of all potential disaster threats on the state communications infrastructure. In the days leading up to landfall, there is significant call volume overload. (During the Hurricane Floyd evacuation in 1999, the Southern Linc system was brought down due to call volume overload).

A significant amount of information traffic must be communicated between the affected coastal areas, shelters (primarily along the I-16 and I-75 corridors) and Atlanta (most state agencies are coordinated through the GEMA State Operations Center in Atlanta, and the American Red Cross Hurricane Watch Team is also based at the Southern Region HQ in Atlanta).

Terrorism

While terrorism has taken center stage in the United States since September 11, 2001, the GEMA has addressed terrorism preparation and training since before the 1996 Olympics and continues to assess and coordinate the state's preparedness activities for terrorism and weapons of mass destruction. Response protocols are addressed in the Georgia Emergency Operations Plan (GEOP) , the State's official guidelines for dealing with preparedness, response and recovery for dealing with natural and manmade hazards impacting Georgians. GEMA has been designated as the lead agency for consequence management of terrorism and the Georgia Bureau of Investigation (GBI) is the lead agency for crisis management of terrorism.

Atlanta has the highest risk for impact due to terrorism. In addition to being the state capital, Atlanta hosts the US Centers for Disease Control (CDC) a few miles northeast of downtown, the worlds busiest airport, Hartsfield International, south of downtown, and three major sports arenas (Turner Field, Philips Arena and the GA Dome) all downtown.

The potential impact to the communications infrastructure can be expected to be both system failure and call volume overload. It is expected that whatever response is required will significantly stress GA Section ARES resources.

Thunderstorms and Lightning

Many hazardous weather events are associated with thunderstorms. Normally, the area affected by any single storm is fairly small and, most of the time, the damage is fairly light. Rainfall from thunderstorms can cause flash flooding, which can change small creeks into raging torrents in a matter of minutes, washing away large boulders and most man-made structures. Hail up to the size of softballs can damage cars and windows, and kills wildlife caught out in the open. Strong (up to more than 120 mph) straight-line winds associated with thunderstorms knock down trees and power lines.

In Georgia, the threat of severe storms is high, particularly in the spring and summer months, although the can occur at any time. Like many of the Gulf Coast states, Georgia tends to receive strong inflows of moisture from the Gulf of Mexico, as well as instability from storm fronts advancing to the east from the mid-west and southern states. Particularly in the late afternoon and evening, many thunderstorms can reach severe levels quickly.

While thunderstorms usually only cause localized damage, storm fronts can advance rapidly across the state, often entering Georgia from either the northwest corner of the state (Dade, Walker and Catoosa Counties) and along the I-20 corridor (Haralson, Carroll, Heard Counties). However, the risk of severe storms should be considered high in all counties in Georgia, as severe storms can develop with or without the existence of frontal boundaries.

The National Weather Service office in Peachtree City provides forecasts and warnings for approximately 2/3 of the state, with 96 counties in its County Warning Area. The remainder of the state is serviced by Jacksonville, FL, Greenville, SC, Columbia, SC, Charleston, SC or Tallahassee Georgia.

Thunderstorms and lightning can damage the local power-grid and can also damage the local telecommunications infrastructure. They rarely result in call volume overload.

The Georgia SKYWARN service activates whenever the National Weather Service requires spotter activity as the result of storms observed by radar or on the ground. The Georgia Section ARES activates as needed to support the SKYWARN nets.

Tornadoes

Georgia is vulnerable to a range of severe and potentially life-threatening weather, including tornadoes. Over the past 50 years, a total of 1,220 tornadoes were reported in Georgia, including 33 in the year 2000.

In Georgia, tornadoes mainly occur during the spring and summer months, usually between the hours of 3:00 p.m. and 9:00 p.m., however they can, and do, occur at any time of the day at any time of year. While tornadoes have occurred in every month of the year in Georgia, the months of March through May are the most active period of tornado activity in the state.

A tornado is a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 250 mph or more. Damage paths can be in excess of one mile wide and 50 miles long. Tornadoes typically move from southwest to northeast at an average forward speed of 30 mph, but they can sometimes be dangerously unpredictable and move in any direction.

Tornadoes are generally produced by thunderstorms, which develop in warm, moist air in advance of eastward-moving cold fronts. These thunderstorms can be dangerous, producing heavy rains, damaging straight-line winds and hail. The most treacherous ones can generate tornadoes. Occasionally, large outbreaks of multiple tornadoes can develop from these systems. Tornadoes can also be generated hundreds of miles inland by hurricanes and tropical storms, for up to a day after they make landfall.

Advances in technology, such as Doppler radar, have steadily improved tornado forecasting over the years, and the warning time has improved. But radar has its limitations and the terrain in many parts of Georgia, particularly the northern part of the state, also makes it difficult to clearly identify a developing tornado and issue a timely warning. For this reason, amateur radio operators trained to identify developing tornadoes are extremely important to the NWS in Georgia.

Since 1950, only two (Taliaferro and Glascock) counties in Georgia have not had at least one tornado event. 53 counties have had at least one presidential disaster declaration due to tornadoes. While tornadoes usually only cause localized damage, storm fronts can advance rapidly across the state. Therefore, the risk of tornado should be considered high in all counties in Georgia, even those with a limited number of historical events.

Tornadoes can damage the local power-grid and can also damage the local telecommunications infrastructure. They rarely result in call volume overload.

The Georgia SKYWARN service activates whenever the National Weather Service requires spotter activity as the result of storms observed by radar or on the ground. The Georgia Section ARES activates as needed to support the SKYWARN nets. Because in some areas, cellular phone and other radio service is limited due to terrain, even when infrastructure damage has not occurred local American Red Cross chapters may need communications assistance with damage assessments and/or shelter communications after the storm has passed.

Winter Storms

A major winter storm can last for several days and be accompanied by high winds, freezing rain or sleet, heavy snowfall, and cold temperatures. People can become trapped at home, without utilities or other services. Heavy snowfall and blizzards can trap motorists in their cars.

Winter storms can make driving and walking extremely hazardous. The aftermath of a winter storm can have an impact on a community or region for days, weeks, or even months. Storm effects such as extremely cold temperatures and snow accumulation, and sometimes coastal flooding, can cause hazardous conditions and hidden problems for people in the affected area.

Georgia is particularly vulnerable to winter storms. The typical winter storm pattern is a front of cold, winter air, advancing from the west/northwest accompanied by a mass of moist, tropical air flowing northeast from the Gulf of Mexico. The nature of the storm depends on where and when the two systems meet.

The threat of winter storm is moderate to high in all areas of the state. 96 counties-including all of the Atlantic Coast counties in southeast Georgia-have had presidential disaster declarations due to winter storms since 1990.

Winter storm conditions can damage the local power-grid and can also damage the local telecommunications infrastructure. Also, conditions could trap operators in their homes, reducing the available ARES resources to respond if needed.


Previous Next


The information on this page is Copyright, © 2001, 2002, American Radio Relay League, Inc. For corrections, updates or questions, please contact ko4wx@arrl.net.