Hazards Impacting Chatham County, GA
These threats have been identified to potentially impact Chatham County, GA.
- Coastal Hazards
Erosion, storm surge, and sea level rise pose risks to coastal areas. Erosion can occur along
coast and in estuarine areas. Loss of land due to erosion is a hazard in itself, if eroded land
contains structures. Erosion also makes an area more vulnerable to other hazards such as storm
e, by removing protective areas. Storm surge is an abnormal rise of water generated by a storm,
and above the predicted astronomical tides. This rise in water level can cause extreme flooding
coastal areas particularly when storm surge coincides with normal high tide, resulting in storm
tides reaching up to 20 feet or more in some cases.
Sea level has been rising over the past century due to thermal expansion of warming ocean waters
and increased ice melt of land-based ice. Due to sea-level rise projected throughout the 21st
century and beyond, coastal systems and low-lying areas will increasingly experience adverse
impacts such as submergence, coastal flooding, and coastal erosion.
- Dam/Levee Failure
A dam or levee failure is the collapse or breach of a dam or levee that causes downstream
flooding. Failures may be caused by natural events, human-caused events, or a combination. Due
to the lack of advance warning, failures resulting from natural events, such as earthquakes or
landslides, may be particularly severe. Prolonged rainfall and subsequent flooding is the most
common cause of dam or levee failure.
Drought is a deficiency in precipitation over an extended period. It is a normal, recurrent
feature of climate that occurs in virtually all climate zones. However, drought can affect
people’s health and safety. It has the potential to impact water supply, agricultural yields,
and water-dependent industries. Drought conditions can also increase the likelihood of wind
erosion and increase wildfire risk.
An earthquake is a movement or shaking of the ground. Most earthquakes are caused by the release
of stresses accumulated as a result of the rupture of rocks along opposing fault planes in the
Earth’s outer crust.
- Extreme Heat
Extreme heat events are one of the leading weather-related causes of death in the United States.
Extreme high temperatures compromise the body’s ability to regulate its temperature, which can
result in a cascade of illnesses and can aggravate chronic conditions. Extreme heat can also
cause damage to infrastructure such as roads and bridges.
Flooding is defined by the rising and overflowing of water onto normally dry land. Flooding can
result from an overflow of inland waters or an unusual accumulation or runoff of surface waters
from any source.
- Hurricane & Tropical Storm
A hurricane is a type of tropical cyclone, a low pressure system that generally forms in the
tropics. A typical cyclone is accompanied by thunderstorms, and in the Northern Hemisphere, a
counterclockwise circulation of winds near the earth’s surface. Hurricanes can cause
catastrophic damage to coastlines and several hundred miles inland. Winds can exceed 155 miles
per hour. Hurricanes and tropical storms can also spawn tornadoes and microbursts, create storm
surges along the coast, and cause extensive damage from heavy rainfall.
- Severe Weather (Thunderstorm Wind, Lightning, and Hail)
Thunderstorms result from the rapid upward movement of warm, moist air. They can occur inside
warm, moist air masses and at fronts. Severe thunderstorm winds arise from convection and have
speeds of at least 58 mph, or are winds of any speed producing a fatality, injury or damage.
Lightning is an electrical discharge between positive and negative regions of a thunderstorm.
Each year, lightning is responsible for deaths, injuries, and millions of dollars in property
damage across the country, including damage to buildings, communications systems, power lines,
and electrical systems. Lightning also causes forest and brush fires.
Hail is associated with thunderstorms that can also bring high winds and tornadoes. It forms
when updrafts carry raindrops into extremely cold areas of the atmosphere where they freeze into
ice. Hailstones are usually less than two inches in diameter and can fall at speeds of 120 mph.
- Severe Winter Storm
Severe winter storm can involve heavy snowfall and/or ice accumulation (generally noted when
accumulation reaches ¼ inch or more), often accompanied by extreme cold, which can result in
blocked roads, dangerous road and sidewalk conditions, downed trees and power lines, and
A tornado appears as a rotating, funnel-shaped cloud that extends from a thunderstorm to the
ground with whirling winds that can reach 300 miles per hour. Damage paths can be in excess of
one mile wide and 50 miles long.
A wildfire is an uncontained fire that spreads through the environment. Wildfires have the
ability to consume large areas, including infrastructure, property, and resources.
- Hazardous Material Incident
A hazardous material is any item or agent (biological, chemical, physical) which has the
potential to cause harm to humans, animals, or the environment, either by itself or through
interaction with other factors. A release or spill of bulk hazardous materials could result in
fire, explosion, toxic cloud or direct contamination of people and property. The effects may
involve a local site or many square miles. Health problems may be immediate, such as corrosive
effects on skin and lungs, or be gradual, such as the development of cancer from a carcinogen.
Damage to property could range from immediate destruction by explosion to permanent
contamination by a persistent hazardous material.
Terrorism is defined in the United States by the Code of Federal Regulations as: “the unlawful
use of force and violence against persons or property to intimidate or coerce a government, the
civilian population, or any segment thereof, in furtherance of political or social objectives.”
A terror threat is generally more likely to be targeted at a critical or symbolic location.