Greenville County Hazards

The Greenville County Hazard Mitigation Plan outlines specific natural hazards that may impact our community.  This list of hazards follows the Hazard Mitigation Plan listing hazards from most common to least common.

Flood

The National Flood Insurance Program (NFIP) reports flooding is the most frequent natural disaster in the United States, with approximately 40% of natural disasters involve flooding at some scale. About 75% of the Presidential Disaster Declarations are flood related. According to the National Weather Service (NWS), flooding has caused over 1,100 deaths since from 2013–2023 (over 8,600 deaths since 1940).

Greenville County is affected by 4 types of flooding:

• Dam/Levee failure
• Local Drainage Problems
• Flash Flooding
• Riverine Flooding

Winter Storms

Greenville County may be impacted by severe winter weather such as ice storms, snow storms, or extremely cold temperatures.  Snow and ice accumulations can damage property, impact roadways, and destroy crops or other valuable timber. 

Wildfires

Wildfires can infringe on developed and/or urban areas and contribute to the structural fire problem. As the population grows and residential developments continue to expand into forested areas, wildland urban interface issues increase and more wildfires threaten homes. Wildfires can occur any time of the year with the height of the wildfire season usually occurring from late winter through spring.  According to the South Carolina Forestry Commission, 98% of the wildland fires are caused by human activities. The leading causes are careless outdoor burning and woods arson.

High Winds / Tornados

Tropical Systems

While Greenville County is not a coastal county, affects from hurricanes and tropical systems can still have an impact on the county.  In September 2024, Hurricane Helene made landfall on the coast of Florida.  The system continued moving north impacting the Update with significant rain and wind, causing widespread damages to homes, businesses, and infrastructure.

Tornados and Hail

Tornados are generally associated with strong thunderstorms.  Tornado activity is most prominent in the Update in the months of March, April, May, and September.  Greenville County has experienced 57 hail events between 2013 and 2023.  

Drought and Excessive Heat

Greenville County typically enjoys a warm subtropical climate.  However, this may also lead to hot and humid days leading to excessive heat and droughts.  

Earthquakes

South Carolina is extremely vulnerable to earthquakes.  Approximately 70% of earthquakes in the state are in the area of the epicenter of the 1886 Charleston/Summerville Earthquake. The Brevard Fault Zone and the Pax Mountain fault system cross into the northern part of Greenville County. In addition to these faults, the county is susceptible to earthquakes in other locations, especially near dams.

Landslides and Sinkholes

Landslides and sinkholes are associated with poorly compacted soil. 

Infectious Diseases or Public Health Emergencies

Infectious disease outbreaks or other public health emergencies may occur in Greenville County with little or no notice. Infectious disease can present special requirements for disease surveillance, rapid delivery of vaccines, antibiotics, or antiviral drugs, allocation of limited medical resources, and expansion of health care services to meet a surge in demand for care.

Communications Failure 

A communications failure is the severe interruption or loss of private and/or public communications systems, including but not limited to transmission lines, broadcast, relay, switching and repeater stations as well as communications satellites, electrical generation capabilities, and associated hardware and software applications necessary to operate communications equipment. These disruptions may result from equipment failure, human acts, (deliberate or accidental) or the results of natural or human made disasters.

Mass Power Failure 

A mass power failure is the loss of commercial power from a public utility company substation, subsidiaries or electric cooperative that affects 1,000 customers for a 24-hour period.

Active Shooter/Hostile Action

An active shooter is an individual(s) actively engaged in killing or attempting to continuously harm people. In most cases, active shooters use firearms, and there is generally no pattern or method to the selection of victims. Active shooter/hostile situations are unpredictable and evolve quickly. An active shooter/hostile   situation could occur anywhere at any time with little or no warning and may result in mass casualties.

Civil Disturbance

Civil disturbances are often the product of increased tension caused by questionable social and/or political events, such as controversial jury trials or law enforcement actions.

Terrorism and Cyber Terrorism

There are many critical and high-profile facilities, high concentrations of the population, and other potentially attractive venues for terrorist activity that make Greenville County vulnerable to a variety of terrorist methods.

Cyber terrorism is a risk for all organizations, including Greenville County government. Though the county uses technology that consists of firewalls, proxy servers, and virus walls to provide a secure perimeter around the network, these can be ineffective when users fail to heed security requirements.

Hazardous Materials Spill or Release

Greenville County has the largest concentration of facilities reporting Extremely Hazardous Substances (EHS) in South Carolina. The county’s industrial capacity and the network of interstate highways and railways result in vulnerabilities to hazardous material releases from both stationary sites and transportation sources.

According to the South Carolina State Hazard Mitigation Plan, Greenville County has the most Toxic Release Inventory (TRI) and Superfund sites in the State.

Nuclear Accident (Fixed)

A fixed nuclear accident is an incident that produces significant amounts of radioactive gases and/or particles which can be released from the facility. Effects can range from a minor release to a radioactive release that would force the evacuation of the general population within a ten mile radius of the facility.  Radioactivity from a release may enter the food chain through crops or dairy products out to a fifty mile radius of the facility. Meteorological conditions can have a significant influence on the size of the contaminated area.

Greenville County is within the 50-mile emergency planning zone of the Oconee Nuclear Station and is a host county for evacuees from Pickens County.

Pipeline Accident

A pipeline accident is the spillage or release, either intentionally or accidentally, of hazardous waste, toxic materials, or natural gas which may cause death or injury to the public and damage or destruction to property and the environment.

Both Colonial Pipeline Company and Kinder Morgan have gas/petroleum pipelines that run through the southern end of Greenville County.  

In June of 1996, Greenville County experienced one of the largest inland oil spills in U.S. history when 957,600 gallons of fuel oil spilled into the Reedy River.