HAZARD IDENTIFICATION Code of Federal Regulations (CFR) Requirement

ALL-HAZARDS MITIGATION PLAN

HAZARD IDENTIFICATION

Code of Federal Regulations (CFR) Requirement

44 CFR Part 201.6(c)(2)(i): The risk assessment shall include a description of the type, location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.

The objectives of the Hazard Identification section are two-fold:

1) Identify hazards that may affect the University of South Carolina

(USC) regional campuses, and

2) Provide a general description of these hazards including the background and state-wide notable occurrences.

Since the USC regional campuses cover most of the state, a general description of state risk and facts are found in this section. (The following section, Section 5: Hazard Analysis, describes specific details on location, spatial extent, historical occurrences, and probably of future occurrence for each campus.) All of the information presented herein is based on existing federal, state and local sources as referenced throughout.

HAZARD SELECTION

South Carolina is vulnerable to a wide range of natural and human-caused hazards that threaten life and property. Current FEMA regulations and interim guidance under the Disaster Mitigation Act of 2000 (DMA 2000) require, at a minimum, an evaluation of a full range of natural hazards. This plan draws on hazards found in the South Carolina State Hazard Mitigation Plan and those suggested under FEMA planning guidance in order to identify a full range of hazards. These hazards were then reviewed by the USC Committee to determine which were relevant to the USC campuses.

University of South Carolina Floodplain Management and Hazard Mitigation Planning Committee

(FMHMPC) reviewed and identified a number of hazards that are to be addressed in the USC

Hazard Mitigation Plan. All of the hazards included underwent an extensive process that utilized input from USC Committee members, research of past disaster declarations for in South Carolina, historical hazard occurrences, and a review of the current South Carolina State Hazard Mitigation

Plan. USC opted to focus on natural hazards in this plan as man-made hazards are identified and planned for in separate planning documents. Readily available online information from reputable sources such as federal and state agencies was also evaluated to supplement information from these key sources.

Table 4.1

lists the full range of natural hazards initially identified for inclusion in the plan and provides a brief description for each. This table includes 24 individual hazards. Some of these hazards are considered to be interrelated or cascading, but for preliminary hazard identification purposes these individual hazards are broken out separately.

Next, Table 4.2

documents the evaluation process used for determining which of the initially identified hazards are considered significant enough for further evaluation in the risk assessment.

HAZARD IDENTIFICATION 4:2

For each hazard considered, the table indicates whether or not the hazard was identified as a significant hazard to be further assessed, how this determination was made, and why this determination was made. The table works to summarize not only those hazards that were identified (and why) but also those that were not identified (and why not). Hazard events not identified for inclusion at this time may be addressed during future evaluations and updates of the risk assessment if deemed necessary by the USC DRU Planning Team during the plan update process.

Table 4.1: Descriptions of the Full Range of Initially Identified Hazards

Hazard Description

ATMOSPHERIC HAZARDS

Avalanche A rapid fall or slide of a large mass of snow down a mountainside.

Drought

Hailstorm

Heat Wave

Hurricane and

Tropical Storm

A prolonged period of less than normal precipitation such that the lack of water causes a serious hydrologic imbalance. Common effects of drought include crop failure, water supply shortages, and fish and wildlife mortality. High temperatures, high winds, and low humidity can worsen drought conditions and also make areas more susceptible to wildfire. Human demands and actions have the ability to hasten or mitigate drought-related impacts on local communities.

Any storm that produces hailstones that fall to the ground; usually used when the amount or size of the hail is considered significant.

Hail is formed when updrafts in thunderstorms carry raindrops into parts of the atmosphere where the temperatures are below freezing.

A heat wave may occur when temperatures hover 10 degrees or more above the average high temperature for the region and last for several weeks. Humid or muggy conditions, which add to the discomfort of high temperatures, occur when a “dome” of high atmospheric pressure traps hazy, damp air near the ground.

Excessively dry and hot conditions can provoke dust storms and low visibility. A heat wave combined with a drought can be very dangerous and have severe economic consequences on a community.

Hurricanes and tropical storms are classified as cyclones and defined as any closed circulation developing around a low-pressure center in which the winds rotate counter-clockwise in the Northern Hemisphere

(or clockwise in the Southern Hemisphere) and with a diameter averaging 10 to 30 miles across. When maximum sustained winds reach or exceed 39 miles per hour, the system is designated a tropical storm, given a name, and is closely monitored by the National

Hurricane Center. When sustained winds reach or exceed 74 miles per hour the storm is deemed a hurricane. The primary damaging forces associated with these storms are high-level sustained winds, heavy precipitation and tornadoes. Coastal areas are also vulnerable to the additional forces of storm surge, wind-driven waves and tidal flooding which can be more destructive than cyclone wind. The majority of hurricanes and tropical storms form in the Atlantic Ocean,

Caribbean Sea and Gulf of Mexico during the official Atlantic hurricane season, which extends from June through November.

University of South Carolina Disaster Resistant University Plan


Lightning

Tornado

Lightning is a discharge of electrical energy resulting from the buildup of positive and negative charges within a thunderstorm, creating a

“bolt” when the buildup of charges becomes strong enough. This flash of light usually occurs within the clouds or between the clouds and the ground. A bolt of lightning can reach temperatures approaching 50,000 degrees Fahrenheit. Lightning rapidly heats the sky as it flashes, but the surrounding air cools following the bolt. This rapid heating and cooling of the surrounding air causes thunder. On average, 73 people are killed each year by lightning strikes in the

United States.

A tornado is a violently rotating column of air that has contact with the ground and is often visible as a funnel cloud. Its vortex rotates cyclonically with wind speeds ranging from as low as 40 mph to as high as 300 mph. Tornadoes are most often generated by thunderstorm activity when cool, dry air intersects and overrides a layer of warm, moist air forcing the warm air to rise rapidly. The destruction caused by tornadoes ranges from light to catastrophic depending on the intensity, size and duration of the storm.

Severe Thunderstorm Thunderstorms are caused by air masses of varying temperatures meeting in the atmosphere. Rapidly rising warm moist air fuels the formation of thunderstorms. Thunderstorms may occur singularly, in lines, or in clusters. They can move through an area very quickly or linger for several hours. Thunderstorms may result in hail, tornadoes, or straight-line winds. Windstorms pose a threat to lives, property, and vital utilities primarily due to the effects of flying debris and can down trees and power lines.

Winter Storm and

Freeze

Winter storms may include snow, sleet, freezing rain, or a mix of these wintry forms of precipitation. Blizzards, the most dangerous of all winter storms, combine low temperatures, heavy snowfall, and winds of at least 35 miles per hour, reducing visibility to only a few yards. Ice storms occur when moisture falls and freezes immediately upon impact on trees, power lines, communication towers, structures, roads and other hard surfaces. Winter storms and ice storms can down trees, cause widespread power outages, damage property, and cause fatalities and injuries to human life.

HYDROLOGIC HAZARDS

Dam and Levee

Failure

Dam failure is the collapse, breach, or other failure of a dam structure resulting in downstream flooding. In the event of a dam failure, the energy of the water stored behind even a small dam is capable of causing loss of life and severe property damage if development exists downstream of the dam. Dam failure can result from natural events, human-induced events, or a combination of the two. The most common cause of dam failure is prolonged rainfall that produces flooding. Failures due to other natural events such as hurricanes, earthquakes or landslides are significant because there is generally little or no advance warning.

Erosion Erosion is the gradual breakdown and movement of land due to both physical and chemical processes of water, wind, and general meteorological conditions. Natural, or geologic, erosion has occurred since the Earth’s formation and continues at a very slow and uniform rate each year.


HAZARD IDENTIFICATION

Flood

4:4

Storm Surge

The accumulation of water within a water body which results in the overflow of excess water onto adjacent lands, usually floodplains.

The floodplain is the land adjoining the channel of a river, stream ocean, lake or other watercourse or water body that is susceptible to flooding. Most floods fall into the following three categories: riverine flooding, coastal flooding, or shallow flooding (where shallow flooding refers to sheet flow, ponding and urban drainage).

A storm surge is a large dome of water often 50 to 100 miles wide and rising anywhere from four to five feet in a Category 1 hurricane up to more than 30 feet in a Category 5 storm. Storm surge heights and associated waves are also dependent upon the shape of the offshore continental shelf (narrow or wide) and the depth of the ocean bottom (bathymetry). A narrow shelf, or one that drops steeply from the shoreline and subsequently produces deep water close to the shoreline, tends to produce a lower surge but higher and more powerful storm waves. Storm surge arrives ahead of a storm’s actual landfall and the more intense the hurricane is, the sooner the surge arrives. Storm surge can be devastating to coastal regions, causing severe beach erosion and property damage along the immediate coast. Further, water rise caused by storm surge can be very rapid, posing a serious threat to those who have not yet evacuated floodprone areas.

GEOLOGIC HAZARDS

Earthquake

Expansive Soils

Landslide

A sudden, rapid shaking of the Earth caused by the breaking and shifting of rock beneath the surface. This movement forces the gradual building and accumulation of energy. Eventually, strain becomes so great that the energy is abruptly released, causing the shaking at the earth’s surface which we know as an earthquake.

Roughly 90 percent of all earthquakes occur at the boundaries where plates meet, although it is possible for earthquakes to occur entirely within plates. Earthquakes can affect hundreds of thousands of square miles; cause damage to property measured in the tens of billions of dollars; result in loss of life and injury to hundreds of thousands of persons; and disrupt the social and economic functioning of the affected area.

Soils that will exhibit some degree of volume change with variations in moisture conditions. The most important properties affecting degree of volume change in a soil are clay mineralogy and the aqueous environment. Expansive soils will exhibit expansion caused by the intake of water and, conversely, will exhibit contraction when moisture is removed by drying. Generally speaking, they often appear sticky when wet, and are characterized by surface cracks when dry. Expansive soils become a problem when structures are built upon them without taking proper design precautions into account with regard to soil type. Cracking in walls and floors can be minor, or can be severe enough for the home to be structurally unsafe.

The movements of a mass of rock, debris, or earth down a slope when the force of gravity pulling down the slope exceeds the strength of the earth materials that comprise to hold it in place. Slopes greater than 10 degrees are more likely to slide, as are slopes where the height from the top of the slope to its toe is greater than 40 feet.



Land

Subsidence/Sinkholes

Tsunami

Volcano

Slopes are also more likely to fail if vegetative cover is low and/or soil water content is high.

The gradual settling or sudden sinking of the Earth’s surface due to the subsurface movement of earth materials. Causes of land subsidence include groundwater pumpage, aquifer system compaction, drainage of organic soils, underground mining, hydrocompaction, natural compaction, sinkholes, and thawing permafrost.

A series of waves generated by an undersea disturbance such as an earthquake. The speed of a tsunami traveling away from its source can range from up to 500 miles per hour in deep water to approximately 20 to 30 miles per hour in shallower areas near coastlines. Tsunamis differ from regular ocean waves in that their currents travel from the water surface all the way down to the sea floor. Wave amplitudes in deep water are typically less than one meter; they are often barely detectable to the human eye. However, as they approach shore, they slow in shallower water, basically causing the waves from behind to effectively “pile up”, and wave heights to increase dramatically. As opposed to typical waves which crash at the shoreline, tsunamis bring with them a continuously flowing ‘wall of water’ with the potential to cause devastating damage in coastal areas located immediately along the shore.

A mountain that opens downward to a reservoir of molten rock below the surface of the earth. While most mountains are created by forces pushing up the earth from below, volcanoes are different in that they are built up over time by an accumulation of their own eruptive products: lava, ash flows, and airborne ash and dust. Volcanoes erupt when pressure from gases and the molten rock beneath becomes strong enough to cause an explosion.

OTHER HAZARDS

Hazardous Materials

Incident

Public Heath

Emergencies

Terror Threat

Hazardous material (HAZMAT) incidents can apply to fixed facilities as well as mobile, transportation-related accidents in the air, by rail, on the nation’s highways and on the water. HAZMAT incidents consist of solid, liquid and/or gaseous contaminants that are released from fixed or mobile containers, whether by accident or by design as with an intentional terrorist attack. A HAZMAT incident can last hours to days, while some chemicals can be corrosive or otherwise damaging over longer periods of time. In addition to the primary release, explosions and/or fires can result from a release, and contaminants can be extended beyond the initial area by persons, vehicles, water, wind and possibly wildlife as well.

Events such as a pandemic that affect a large number of the population.

Terrorism is defined by FEMA as, “the use of force or violence against persons or property in violation of the criminal laws of the United

States for purposes of intimidation, coercion, or ransom.” Terrorist acts may include assassinations, kidnappings, hijackings, bomb scares and bombings, cyber-attacks (computer-based), and the use of chemical, biological, nuclear and radiological weapons.



Sea Level Rise

Wildfire

4:6

According to NOAA, sea level rise is defined as a mean rise is sea level. As the ocean warms, sea water expands and continental ice sheets melt, thus inundating areas with sea water that were previously above sea level.

An uncontrolled fire burning in an area of vegetative fuels such as grasslands, brush, or woodlands. Heavier fuels with high continuity, steep slopes, high temperatures, low humidity, low rainfall, and high winds all work to increase risk for people and property located within wildfire hazard areas or along the urban/wildland interface. Wildfires are part of the natural management of forest ecosystems, but most are caused by human factors. Over 80 percent of forest fires are started by negligent human behavior such as smoking in wooded areas or improperly extinguishing campfires. The second most common cause for wildfire is lightning.



Table 4.2: Documentation of the Hazard Evaluation Process

Natural

Hazards

Considered

Was this hazard identified as significant enough to be addressed in the plan?

(Yes or No)

ATMOSPHERIC HAZARDS

Avalanche NO

How was this determination made?

Why was this determination made?

Drought

Hailstorm

Heat Wave

YES

YES

YES

 Review of US

Forest Service

National



Avalanche

Center web site

Review of the SC

State Hazard

Mitigation Plan

 Review of the SC

State Hazard

Mitigation Plan

 Review of

Previous

Occurrences from NCDC

 Review of information from the SC

Climatology

Office

 Review of SC

State Hazard



Mitigation Plan

Review of FEMA’s

Multi-Hazard



Identification and Risk

Assessment

Review of NOAA

NCDC Storm

Events Database

 Review of NOAA

NCDC Storm

Events Database


State Hazard

Mitigation Plan

 There is no risk of avalanche events in South Carolina. The

United States avalanche hazard is limited to mountainous western states including Alaska, as well as some areas of low risk in New

England.

 Avalanche hazard was not considered in the South Carolina

State Hazard Mitigation Plan.

 Droughts are evaluated in SC

State Hazard Mitigation Plan.

 According to NCDC, there have been 64 drought occurrences between 1950 and 2010 in the state of South Carolina. Most of the USC DRU campuses have experienced drought conditions.

 The SC Climatology Office reported maximum temperatures for each county well over 100 degrees Fahrenheit throughout the planning area.

 Hail events are discussed in the state plan.

 NCDC reports 4,221 hailstorm events (0.75 inch sized hail to

2.75 inches) in South Carolina between 1958 and March 2010.

 NCDC reported 24 extreme heat events between 1950 and March

2010 in South Carolina.

 The SC State Hazard Mitigation

Plan includes Extreme Heat as a hazard.




Natural

Hazards

Considered

Hurricane and

Tropical Storm


(Yes or No)

YES



Lightning

Tornado

YES

YES

 Review of SC

State Hazard

Mitigation Plan

 Analysis of NOAA historical tropical cyclone tracks and National

Hurricane Center

Website

Review of NOAA 

NCDC Storm

Events Database

 Review of historical presidential disaster declarations

 FEMA Hazus-MH storm return periods

 Review of SC

State Hazard

Mitigation Plan

 Review of FEMA’s

Multi-Hazard


Assessment

 Review of NOAA

NCDC Storm

Events Database,

NOAA lightning statistics

 Review of SC

State Hazard

Mitigation Plan


Multi-Hazard


Assessment

 Hurricane and tropical storm events are evaluated in the state plan.

 NCDC reported 42 Hurricane and

Tropical Storm events in the state of South Carolina between

1950 and March 2010.

 NOAA’s NHC historical records indicate every USC DRU campus has been affected by a hurricane or tropical storm event.

 Three out of eight disaster declarations affecting the USC

DRU counties, five are directly related to hurricane and tropical storm events.

 The 50-year return period peak gust for hurricane and tropical storm events is between 58 mph

(Upstate campus) and 101 mph

(Baruch).

 Lightning events are discussed in the state plan.

 NCDC reported 391 lightning events in South Carolina between

1950 and March 2010. These events have resulted in a recorded 23 deaths, 92 injuries and several million in property damage.

 Tornado events are discussed in the SC State Hazard Mitigation

Plan.

 NCDC reported 924 tornado events in South Carolina between

1950 and March 2010. These events resulted in 56 reported deaths, 1,303 injuries, and




Natural

Hazards

Considered


(Yes or No)



 Review of NOAA

NCDC Storm

Events Database several million in property damage.

4:9

Severe

Thunderstorm

YES

Winter and Freeze

Storm YES


Dam and Levee

Failure

NO

University of South Carolina

 Review of SC

State Hazard

Mitigation Plan


Multi-Hazard


Assessment

 Review of NOAA

NCDC Storm

Events Database

 Review of SC

State Hazard

Mitigation Plan


Multi-Hazard


Assessment

 Review of historical presidential disaster declarations.

 Review of NOAA

NCDC Storm

Events Database

 Thunderstorm events are discussed in the SC State Hazard

Mitigation Plan.

 NCDC reports 7,373 thunderstorm events in South

Carolina between 1950 and

March 2010. These events resulted in several million in property damages.

 Winter Storms including snow storms and ice storms are evaluated in the state plan.

 NCDC reported 226 snow and ice events in South Carolina between

1950 and March 2010. These events resulted in 2 reported deaths, 24 injuries and several million in damages.

 Of the eight disaster declarations affecting the USC DRU counties, two were directly to winter storm events.

 Review of SC

State Hazard

Mitigation Plan

 USC Committee input

 Dam Failure is discussed in the state plan.

 USC Committee were not aware of any dams that would affect the

USC DRU campuses. Further, this hazard was classified as a manmade hazard though may be triggered by a natural event.

Disaster Resistant University Plan



Natural

Hazards

Considered

Erosion


(Yes or No)

YES



Flood

Storm Surge

YES

YES

 Review of SC

State Hazard

Mitigation Plan


Multi-Hazard


Assessment

 Review of SC

State Hazard

Mitigation Plan

 Review of historical disaster declarations

 Review of NOAA

NCDC Storm

Events Database

 Review of FEMA

DFIRM flood data

 Review of SC

State Hazard

Mitigation Plan

 Review of NOAA

NCDC Storm

Events Database

 Coastal erosion is discussed in the state plan but only for coastal areas (no discussion of riverine erosion).

 The flood hazard is thoroughly discussed in the state plan.

 Two out of eight Presidential



Disaster Declarations were floodrelated.

NCDC reported 820 flood events in South Carolina between 1950 and March 2010. These events in total caused 8 reported deaths,

19 injuries, and over $1billion in property damages (2010 dollars).

 Not all campuses have digital flood data available. A preliminary visual assessment indicates that flood may be an issue on some campuses.

 Storm surge is not discussed in the state plan.

 Six surge events were reported for the state of South Carolina by

NCDC between 1950 and March

2010. Three of these affected

Georgetown County, a USC DRU participating campus is located.

 Given the coastal location of some campuses, Storm Surge is a significant hazard.

GEOLOGIC HAZARDS

Earthquake YES  Review of SC

State Hazard

Mitigation Plan

 USGS

Earthquake

 Earthquake events are discussed in the state plan.

 Earthquakes have occurred in and around the State of South

Carolina in the past. The state is




Natural

Hazards

Considered


(Yes or No)



Expansive Soils

Landslide

NO

NO

Hazards Program web site

 Review of the

National

Geophysical Data

Center


Multi-Hazard


Assessment

 Review of SC

State Hazard

Mitigation Plan


Multi-Hazard


Assessment

 Review of USDA

Soil Conservation

Service’s Soil

Survey

 Review of SC

State Hazard



Mitigation Plan

Review of USGS

Landslide

Incidence and



 affected by the Charleston and the New Madrid (near Missouri)

Fault lines which have generated a magnitude 8.0 earthquake in the last 200 years.

Over 1,000 events are known to have occurred in the state according to the National

Geophysical Data Center (1886 to 1985). Sixty-seven of these events affected a USC DRU county. The greatest MMI reported was an 8.

According to USGS seismic hazard maps, the peak ground acceleration (PGA) with a 10% probability of exceedance in 50 years across the state of South

Carolina is at least 4%g and goes to the maximum of 15%g. FEMA recommends that earthquakes be further evaluated for mitigation purposes in areas with a PGA of

3%g or more.

 Expansive soils are not identified in the state plan.

 According to FEMA and USDA sources, a majority of the planning areas have clays with little to no swelling potential.

 Landslide events are discussed in the state plan.

 USGS landslide hazard maps indicate “high susceptibility with low to moderate incidence” in the

Upstate area of the state. A




Natural

Hazards

Considered


(Yes or No)



Land

Subsidence/

Sinkholes

Tsunami

Volcano

NO

NO

NO

Susceptibility

Hazard Map

 Review of the

South Carolina

Geological

Survey (SCGS)

 Review of SC

State Hazard

Mitigation Plan

 Review of SC

State Hazard

Mitigation Plan


Multi-Hazard


Assessment

 Review of FEMA

“How-to” mitigation planning guidance

(Publication 386-

2,

“Understanding

Your Risks –

Identifying

Hazards and

Estimating

Losses).

 Review of SC

State Hazard

Mitigation Plan

 Review of USGS

Volcano Hazards

Program web site majority of the state received a low incidence rating.

 Information provided by SCGS indicated that no major landslide events have occurred in the state

(no loss of life or property damage) and no recording mechanisms are in place to capture minor events.

 The state plan indicates that there are no known sinkhole occurrences in the state.

 Tsunamis are discussed in the state plan.

 No record exists of a catastrophic

Atlantic basin tsunami impacting the mid-Atlantic coast of the

United States.

 Tsunami inundation zone maps are not available for communities

 located along the U.S. East

Coast.

FEMA mitigation planning guidance suggests that locations along the U.S. East Coast have a relatively low tsunami risk and need not conduct a tsunami risk assessment at this time.

 There are no active volcanoes in

South Carolina.

 No volcanoes are located remotely near the state.




Natural

Hazards

Considered


(Yes or No)

OTHER HAZARDS

Dam and Levee

Failure

NO

Hazardous

Materials

Incident

NO


 Review of SC

State Hazard



Mitigation Plan

USC Committee input

 USC Committee input


 Dam Failure is evaluated for the state.

 No known dams are known to affect the USC campuses.

Therefore, this hazard was omitted.

 The USC DRU plan only includes natural hazards. Man-made hazards are addressed in other university planning documents.

Public Health

Emergency

NO

Sea Level Rise YES

Terror Threat

Wildfire

NO

YES

University of South Carolina




State Hazard

Mitigation Plan

 Input from USC

DRU Committee



Input from USC

DRU Committee

Input from USC

DRU Committee


 Sea Level Rise is not discussed in the state plan.

 The USC DRU Committee would like Sea Level included and data exists to complete the analysis and vulnerability assessment.


 Review of SC

State Hazard



Mitigation Plan

Review of

Southern Wildfire

Risk Assessment

(SWRA) Data


Division of Forest

Resources website

 Wildfires are discussed in the state plan.

 A preliminary review of SWRA data indicates that is wildfire risk on many of the USC campuses.

 According to the North Carolina

Division of Forest Resources, each USC DRU campus has had historical wildfire events.

 Wildfire hazard risks will increase as low-density development along the urban/wildland interface increases.

Disaster Resistant University Plan


The following hazards were identified for the USC DRU plan based on the information provided above and are subsequently described below in Table 4.3

:

Table 4.3: USC DRU HAZARDS

ATMOSPHERIC HAZARDS GEOLOGIC HAZARDS



Drought



Extreme Heat



Hail



Hurricane and Coastal Storm Wind



Earthquake



Landslide

OTHER HAZARDS



Lightning



Severe Thunderstorm



Tornado



Winter Storm and Freeze




Coastal Erosion



Flood



Storm Surge



Sea Level Rise



Wildfire

The description of the following hazards provides an overview of each hazard and it’s affect on the state. In the subsequent section, Section 5: Hazard Analysis , the impact of each hazard on each regional campus location is addressed.

Background

A drought occurs when a prolonged period of less than normal precipitation results in a serious hydrologic imbalance. Drought is a natural climatic condition caused by an extended period of limited rainfall. High temperatures, high winds and low humidity can worsen drought conditions, and can make areas more susceptible to wildfire. Human demands and actions can also hasten drought-related impacts. Humans may also alleviate drought impacts by reduced water use.

Common effects of drought include crop failure, water supply shortages, and fish and wildlife mortality.

Droughts are frequently classified as one of following four types: meteorological, agricultural, hydrological or socio-economic. Meteorological droughts are typically defined by the level of

“dryness” when compared to an average, or normal amount of precipitation over a given period of time. Agricultural droughts relate common characteristics of drought to their specific agriculturalrelated impacts. Hydrological drought is directly related to the effect of precipitation shortfalls on surface and groundwater supplies. Human factors, particularly changes in land use, can alter the hydrologic characteristics of a basin. Socio-economic drought is the result of water shortages that limit the ability to supply water-dependent products in the marketplace.

Figure 4.1

shows the Palmer Drought Severity Index (PDSI) Summary Map for the United States from 1895 to 1995. PDSI drought classifications are based on observed drought conditions and range from -0.5 (incipient dry spell) to -4.0 (extreme drought). As can be seen, the Eastern United

States has historically not seen as many significant long-term droughts as the Central and Western regions of the country.



Figure 4.1: Palmer Drought Severity Index Summary Map for the U.S.

4:15

Source: National Drought Mitigation Center (data for 1895 to 1995)

Location and Spatial Extent

Drought typically impacts a large area that cannot be confined to any geographic boundaries.

However, some regions of the United States are more susceptible to drought conditions than others. According to the Palmer Drought Severity Index (PDSI) Summary Map for the United

States, South Carolina is in a zone of less than 5 percent to 9.99 percent PDSI less than or equal to

-3 (-3 indicating severe drought conditions). This indicates that drought conditions are a relatively low to moderate risk for South Carolina. It is assumed that the entire state is exposed to this hazard and that the spatial extent of that impact is large. It is important to note that drought conditions typically do not cause significant damage to the built environment. Drought effects are most directly felt by agricultural sectors, but at times may also cause community-wide impacts as a result of acute water shortages (regulatory use restrictions, drinking water supply and salt water intrusion).

Historical Occurrences

The most recent recorded drought cycle in South Carolina was in 2009, which affected nine counties. This event ended in December when most of the state received 150 percent to 300 percent of their normal rainfall amounts between November and December. As with any drought event, the governor and the Department of Natural Resources urged water use restrictions.

Notable Drought Events in South Carolina



February through November 1925: The drought of 1925 caused the state to experience rainfall deficits reaching 18.23 inches. The growing season alone had a recorded 12.41-inch rain deficit.

Livestock water was scarce, deep wells went dry and hydroelectric power was non-existent.

January through December 1954: Total statewide precipitation for that year was a mere 32.96 inches, which set the current record for driest year ever recorded in the state. An excessively hot summer only exacerbated its impact. According to National Weather Service reports, the crop yield was only 10 percent of its 10-year average production rate.

May through August 1993: Many locations in South Carolina broke records during the 1993 drought. For example, in July of 1993, Greenville-Spartanburg Airport recorded the hottest and driest month on record. Nine daily record high temperatures were also set at the Greenville-

Spartanburg Airport during July 1993. Only 0.75" of rain was recorded during July 1993 making it the driest July on record since 0.80'" in July 1977. Similar records were set at locations around the state. The drought and record heat cost the State a total of $225 1 million crop losses, including

$63.9 million for corn, $55.1 million for vegetables and fruits, $47.2 million for tobacco, $31.7 million for cotton and $27.8 million for soybeans. The drought, which started at the height of the crop growing season in May and June, devastated South Carolina pastures and hay production. The total loss for livestock, hay and pasture was estimated at $34.7 million.

March through May, 1995: Below normal rainfall from March through May reduced the potential wheat yield approximately 30 percent, causing an estimated $20 million in crop damages and losses. Water use was restricted at a few locations in the southeastern part of state.

1998–2002. The drought resulted in significantly reduced streamflows across the state. The hydrologic-drought impacted water supplies, irrigation capacity and many lake-related businesses, including golf courses. In addition, the drought caused numerous agricultural problems. For example, the drought significantly contributed to the southern pine beetle epidemic. Trees weakened by drought are more susceptible to the tree-killing beetles, which significantly increased wildfire vulnerability. Agricultural impacts range from limited water for livestock, reduced feed crops, and lowered crop quality. In 1998 and 2002, a natural disaster was declared for most of

South Carolina’s 46 counties by the United States Department of Agriculture.

Recent Drought Activity

According to NCDC records, there were forty-six drought events in South Carolina since 2001. No fatalities, injuries, property, or crop damage were associated with these mild to moderate drought events.

Probability of Future Events

It can be expected that future drought events will continue to affect the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .

1 Clemson University Cooperative Extension Service



EXTREME HEAT

Background

Extreme heat is defined as temperatures that hover 10 degrees or more above the average high temperature for the region and that last for an extended period of time. A heat wave may occur when temperatures hover 10 degrees or more above the average high temperature for the region and last for several weeks. Humid conditions may also add to the discomfort of high temperatures.

While extreme heat does not typically affect buildings, the impact to the population can have grave effects. Health risks from extreme heat include heat cramps, heat fainting, heat exhaustion and heat stroke. According to the National Weather Service (which compiles data from the National

Climatic Data Center), heat is the leading weather-related killer in the United States. During the ten-year period between 2000 and 2009 heat events killed 162 people - more people than lightning, tornado, flood, cold, winter storm, wind and hurricane hazards. However, most deaths are attributed to prolonged heat waves in large cities that rarely experience hot weather. The elderly and the ill are most at-risk, along with those who exercise outdoors in hot, humid weather.

Figure 4.2

uses air temperature and humidity to determine the heat index or apparent temperature.

Table 4.4

shows the dangers associated with different heat index temperatures.

Some populations, such as the elderly and young, are more susceptible to heat danger than other segments of the population

Figure 4.2: Heat Index Chart

Source: NOAA



Table 4.4:

Heat Disorders Associated with Heat Index Temperature

Heat Index Temperature

(Fahrenheit)

Description of Risks

80°- 90°

90°- 105°

105°- 130°

Fatigue possible with prolonged exposure and/or physical activity

Sunstroke, heat cramps, and heat exhaustion possible with prolonged exposure and/or physical activity

Sunstroke, heat cramps, and heat exhaustion likely, and heatstroke possible with prolonged exposure and/or physical activity

130° or higher Heatstroke or sunstroke is highly likely with continued exposure

Source: National Weather Service, NOAA


Extreme temperatures typically impact a large area that cannot be confined to any geographic boundaries. Therefore, it is assumed that all of the USC campuses are uniformly exposed to this hazard and that the spatial extent of impact would be large. It is important to note however, that extreme temperatures typically do not cause significant damage to the built environment.


According to the National Weather Service, three heat-related fatalities occurred in South Carolina between 2000 and 2009.

Table 4.5 below shows the breakdown of fatalities by year.

Table 4.5: Heat-Related Deaths in South Carolina

YEAR NUMBER OF DEATHS

2000

2001

2002

2003

1

0

0

0

2004

2005

2006

2007

2008

2009

0

0

0

1

0

1

TOTAL 3

Source: National Weather Service


It can be expected that future heat events will affect the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .



HAIL

Background

Hailstorms are a potentially damaging outgrowth of severe thunderstorms. Early in the developmental stages of a hailstorm, ice crystals form within a low-pressure front due to the rapid rising of warm air into the upper atmosphere and the subsequent cooling of the air mass. Frozen droplets gradually accumulate on the ice crystals until they develop to a sufficient weight and fall as precipitation. Hail typically takes the form of spheres or irregularly-shaped masses greater than

0.75 inches in diameter. The size of hailstones is a direct function of the size and severity of the storm. High velocity updraft winds are required to keep hail in suspension in thunderclouds. The strength of the updraft is a function of the intensity of heating at the Earth’s surface. Higher temperature gradients relative to elevation above the surface result in increased suspension time and hailstone size.

Table 4.6 below shows the typical damage associated with different sizes of hail.

Table 4.6: TORRO Hailstorm Intensity Scale

Intensity

Category

5

H0

Hard Hail

H1

Potentially

Damaging

5-

15

H2

Significant 10-

20

Typical

Hail

Diameter

(mm)

*

0-20

>20

>100

Probable Kinetic

Energy, J-m

2

No damage

Slight general damage to plants, crops

H3

Severe

H4

Severe

20-

30

25-

40

H5

Destructive 30-

50

H6

Destructive 40-

60

H7

Destructive 50-

75

H8

Destructive 60-

90

>300

>500

>800

H9

Super

Hailstorms

75-

100

H10

Super

Hailstorms

>100

Source: http://www.torro.org.uk/site/hscale.php

Significant damage to fruit, crops, vegetation

Severe damage to fruit and crops, damage to glass and plastic structures, paint and wood scored

Widespread glass damage, vehicle bodywork damage

Wholesale destruction of glass, damage to tiled roofs, significant risk of injuries

Bodywork of grounded aircraft dented, brick walls pitted

Severe roof damage, risk of serious injuries

(Severest recorded in the British Isles) Severe damage to aircraft bodywork

Extensive structural damage. Risk of severe or even fatal injuries to persons caught in the open

Extensive structural damage. Risk of severe or even fatal injuries to persons caught in the open

Typical Damage Impacts




Hailstorms frequently accompany thunderstorms, so their locations and spatial extents coincide.

Thunderstorms are atmospheric in nature and thus threaten the entire state of South Carolina.

Therefore, hail has the potential to impact the entire state as well.


According to the National Climatic Data Center, 4,221 recorded hail events have affected South

Carolina since 1950.

2 Events specific to each campus location can be found in Section 5: Hazard

Analysis.

Notable South Carolina Hail Events

April 24, 1999: A super cell thunderstorm moved through Saluda County and produced hail, some as large as baseballs, along its entire path. Homes, buildings, farm equipment, vehicles, and crops were damaged. The thunderstorm, including the associated hail, caused damages across a threemile wide swath. Property damages were estimated to be $2 million, crop damages were estimated to be $2 million, and two injuries were reported.

August 20, 1999 : Severe thunderstorms developed across the Upstate, causing damaging straight-line winds and hail. Dime to ping-pong ball size hail was reported from near Stumphouse

Mountain to Walhalla. Various reports of hail ranging from dime to quarter size were reported from

Oconee, Anderson, Laurens and Greenville counties. Golf ball to grapefruit-size hail was reported in

Greenville and Spartanburg counties. Roof damage, as well as damage to vehicles and windows, was widely reported. Damage estimates, considered to be quite conservative, were approximately

$1 million.

May 25, 2000: A severe thunderstorm caused straight-line winds and dime size hail in Darlington, as well as 2-inch hailstones to the south of the city. Property damage was estimated at $150,000.

The County Agricultural Service reported several areas of crop damage near Highway 401, estimated at $10,000. In Florence, a severe thunderstorm caused large hail and wind gusts estimated at over 80 mph. The largest hail size was estimated at over four inches in diameter, causing extensive damage to roof and siding. Approximately 2,000 homes were damaged, with repair costs exceeding 6 million dollars. The storm knocked out power to over 20,000 residences.

Two injuries were reported due to broken glass impacted by hail.


It can be expected that future hail events will continue to cause minor damages to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard

Analysis .

2 These hail events are only inclusive of those reported by the National Climatic Data Center (NCDC). It is likely that additional hail events have affected the state of South Carolina. As additional local data becomes available, this hazard profile will be amended.



HURRICANE AND TROPICAL STORM

Background

Hurricanes and tropical storms are classified as cyclones and defined as any closed circulation developing around a low-pressure center in which the winds rotate counter-clockwise in the

Northern Hemisphere (or clockwise in the Southern Hemisphere) and whose diameter averages 10 to 30 miles across. A tropical cyclone refers to any such circulation that develops over tropical waters. Tropical cyclones act as a “safety-valve,” limiting the continued build-up of heat and energy in tropical regions by maintaining the atmospheric heat and moisture balance between the tropics and the pole-ward latitudes. The primary damaging forces associated with these storms are high-level sustained winds, heavy precipitation and tornadoes. Coastal areas are also vulnerable to the additional forces of storm surge, wind-driven waves and tidal flooding which can be more destructive than cyclone wind.

The key energy source for a tropical cyclone is the release of latent heat from the condensation of warm water. Their formation requires a low-pressure disturbance, warm sea surface temperature, rotational force from the spinning of the earth and the absence of wind shear in the lowest 50,000 feet of the atmosphere. The majority of hurricanes and tropical storms form in the Atlantic Ocean,

Caribbean Sea and Gulf of Mexico during the official Atlantic hurricane season, which encompasses the months of June through November. The peak of the Atlantic hurricane season is in early to mid-September and the average number of storms that reach hurricane intensity per year in this basin is about six (6).

Figure 4.3

shows for any particular location what the chance is that a tropical storm or hurricane will affect the area sometime during the Atlantic hurricane season. (Land is outlined in black, showing Florida and the South Carolina coast in the top left quadrant.) This illustration was created by the National Oceanic and Atmospheric Administration’s Hurricane Research Division using data from 1944 to 1999 and counting hits when a storm or hurricane was within approximately 100 miles (165 km) of each location.



Figure 4.3: Empirical Probability of a Named Hurricane or Tropical Storm

4:22

Source: National Oceanic and Atmospheric Administration, Hurricane Research Division

As an early hurricane develops, barometric pressure (measured in millibars or inches) at its center falls and winds increase. If the atmospheric and oceanic conditions are favorable, it can intensify into a tropical depression. When maximum sustained winds reach or exceed 39 miles per hour, the system is designated a tropical storm, given a name, and is closely monitored by the National

Hurricane Center in Miami, Florida. When sustained winds reach or exceed 74 miles per hour the storm is deemed a hurricane. Hurricane intensity is further classified by the Saffir-Simpson Scale, which rates hurricane intensity on a scale of 1 to 5, with 5 being the most intense. The Saffir-

Simpson Scale is shown in Table 4.7

.

Table 4.7: Saffir-Simpson Scale

CATEGORY

MAXIMUM

WIND SPEED (MPH)

SUSTAINED MINIMUM SURFACE

PRESSURE (MILLIBARS)

STORM SURGE

(FEET)

1

2

3

4

5

74 – 95

96 – 110

111 – 130

131 – 155

155 +

Greater than 980

979 – 965

964 – 945

944 – 920

Less than 920

3 – 5

6 – 8

9 – 12

13 – 18

19+

Source: National Hurricane Center

The Saffir-Simpson Scale categorizes hurricane intensity linearly based upon maximum sustained winds, barometric pressure and storm surge potential, which are combined to estimate potential damage. Categories 3, 4, and 5 are classified as “major” hurricanes, and while hurricanes within this range comprise only 20 percent of total tropical cyclone landfalls, they account for over 70


HAZARD IDENTIFICATION 4:23 percent of the damage in the United States. Table 4.8

describes the damage that could be expected for each category of hurricane.

Damage during hurricanes may also result from spawned tornadoes, storm surge and inland flooding associated with heavy rainfall that usually accompanies these storms.

Table 4.8: Hurricane Damage Classifications

STORM DAMAGE

DESCRIPTION OF DAMAGES

PHOTO

EXAMPLE

1 MINIMAL

No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also, some coastal flooding and minor pier damage.

2

3

MODERATE

EXTENSIVE

Some roofing material, door, and window damage. Considerable damage to vegetation, mobile homes, etc. Flooding damages piers and small craft in unprotected moorings may break their moorings.

Some structural damage to small residences and utility buildings, with a minor amount of curtain wall failures. Mobile homes are destroyed.

Flooding near the coast destroys smaller structures, with larger structures damaged by floating debris. Terrain may be flooded well inland.

4 EXTREME

More extensive curtain wall failures with some complete roof structure failure on small residences. Major erosion of beach areas. Terrain may be flooded well inland.

5 CATASTROPHIC

Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Flooding causes major damage to lower floors of all structures near the shoreline. Massive evacuation of residential areas may be required.

Sources: National Hurricane Center; Federal Emergency Management Agency


South Carolina remains one of them most vulnerable states in the U.S. to hurricanes and tropical storms. Fourteen hurricanes have made landfall along the South Carolina coast since 1900.

According to the National Hurricane Center HURDAT data, there were seventy (70) land falling hurricanes or tropical storm in South Carolina between 1900 and 2009. Between 1984 and 2010, the USC DRU counties received five presidential disaster declarations specifically for hurricanes and tropical storms, out of eight total declarations. The last reported hurricane or tropical storm-related presidential disaster declaration was in 2004. A major hurricane has not impacted the state in several years.

According to Figure 4.1, the empirical probability of a tropical storm or hurricane affecting the state of South Carolina is between 12 and 36 percent each hurricane season. As indicated in the figure, coastal areas of South Carolina are a greater risk to hurricanes and tropical storms than the inland areas. This estimated probability is fairly consistent with observed historical storm data provided by

NOAA’s National Hurricane Center and the South Carolina Office of Emergency Management.




Information in this subsection was collected and adapted from National Hurricane Center, National

Climatic Data Center and National Weather Service historical records in addition to the South

Carolina Hazard Mitigation Plan, South Carolina Emergency Management, and local information.

Since 1850, 70 hurricane or tropical storm tracks have passed through South Carolina.

3 This includes: zero (0) Category 5 hurricanes; one (1) Category 4 hurricanes; four (4) Category 3 hurricanes; six (6) Category 2 hurricanes; seventeen (17) Category 1 hurricanes; and forty-two

(42) tropical storms. Tracks that affected each USC regional campus are highlighted in Section 5, including the date of occurrence, maximum wind speed, and category based on the Saffir-Simpson

Scale.

Details of the most notable hurricane events in South Carolina history are presented below.

Notable Hurricane Events in South Carolina

Great Sea Island Storm of 1893 (August 27–28, 1893): One of the deadliest hurricanes to strike the United States, this storm made landfall in Georgia at high tide bringing a tremendous storm surge that created a “tidal wave” effect that swept over and submerged whole islands. The storm’s north-northeast track through the South Carolina midlands brought winds of between 96 mph and 125 mph, with maximum winds of 125 mph in the Beaufort area and up to 120 mph in

Charleston. Major damages were reported as the storm moved north near Columbia and then northeast through the remainder of the state, causing between 2,000 and 2,500 deaths, an estimated $10 million in damages, and leaving 20,000 to 30,000 victims homeless.

Hurricane Hazel (October 15, 1954): Hazel made landfall in South Carolina as a Category 3 hurricane near Little River bringing tides of up to 16.9 feet. The storm caused 95 deaths in North and South Carolina. Approximately $27 million in damages was reported. Hurricane Hazel is considered one of the most severe storms to hit South Carolina to date.

Hurricane Gracie (September 29, 1959): Gracie, a Category 3 hurricane, made landfall at St.

Helena Island with winds of 140 mph, moving northwest before weakening to a tropical storm as it passed through Columbia and turned north-northwest on a path into North Carolina. Beach tides reached nearly six feet above normal. Several fatalities, as well as property damage, were reported along the southern coastal area. Heavy crop damage occurred, and moderate to heavy flooding was reported due to six to eight inches of rainfall.

Hurricane Hugo (September 21, 1989): Hugo, a Category 4 hurricane, made landfall at Isle of

Palms, South Carolina with sustained winds of 140 mph and wind gusts exceeding 160 mph. Hugo is the costliest storm in South Carolina history, causing over $8 billion in damages to property and crops in the United States and the first major hurricane to strike the state since Gracie in 1959.

Total damages, including those that occurred in Puerto Rico and the Caribbean, exceeded 10 billion dollars. Hurricane Hugo resulted in 35 storm-related fatalities, twenty of which occurred in South

Carolina. Seven of the South Carolina fatalities occurred in mobile home parks northwest of

Charleston. The strongest winds passed over the Francis Marion National Forest between Bulls Bay and the Santee River. The Forest Service estimated that timber losses exceeded $100 million.

While the most severe winds occurred to the northeast of Charleston, the city was hard hit.

Charleston City Hall and the fire station lost their roofs and over 4,000 historic properties were damaged. Coastal storm surge reached 20 feet in some areas, making it the highest ever recorded in the state. Folly Beach was among the most significantly impacted coastal communities.

3 These storm track statistics do not include tropical depressions or extra tropical storms. Though these related hazard events are less severe in intensity, they may indeed cause significant local impact in terms of rainfall and high winds.



Approximately 80 percent of the homes were destroyed. Sullivan’s Island and the Isle of Palms were also severely damaged. Numerous homes were knocked off their foundations and boats in the local marina were tossed into a 50 foot high pile of debris. Severe inland wind damage occurred as winds gusting to 109 mph at Sumter were reported. The hurricane exited the state just north of

Rock Hill, causing significant damage in Charlotte, North Carolina. South Carolina received a

Presidential Disaster Declaration for this event.

Hurricane Fran (September 5, 1996): Although Hurricane Fran skirted the South Carolina coast before making landfall at the entrance of the Cape Fear River in North Carolina, it triggered the evacuation of 500,000 tourists in the coastal areas of both states, creating the largest peacetime evacuation in U.S. history. Wind gusts of 60 mph were reported along the Horry County coast. In

Georgetown County, 57 mph winds in the City of Georgetown contributed to $150,000 in county government infrastructure damage. Eleven evacuation shelters housed 5,400 people. One death was attributed to the storm. In Horry County, agricultural losses of $19.8 million were reported, with corn, tobacco and sweet potato crops hardest hit. Downed trees caused power outages affecting about 60,000 customers. Horry County reported property losses totaling over $1 million, including $448,000 at North Myrtle Beach, $341,000 at Myrtle Beach, $42,000 at Surfside Beach,

$46,000 at Garden City Beach, and $135,000 in unincorporated areas. South Carolina received a

Presidential Disaster Declaration for this event.

Hurricane Bonnie (August 26, 1998): The center of Hurricane Bonnie came within 70 miles of the Horry County coast as the storm tracked north during the afternoon and early evening. Wind reports were as high as 82 mph at the Cherry Grove pier and 76 mph at the Myrtle Beach Pavilion.

Reported rainfall was between two and four inches. Downed trees and power lines caused some structural damages. Estimated property damages were reported to be $3.8 million and the State of

South Carolina received a federal disaster declaration.

Hurricane Floyd (September 15, 1999): Hurricane Floyd weakened to a Category 3 hurricane as it approached the southeast Georgia and southern South Carolina coasts on the morning of

September 15. The storm skirted the coast, its center moving northeast about 60 miles offshore late in the afternoon and early evening as it took a more north and northeast course toward North

Carolina. Sustained winds of tropical storm force were reported from Savannah, Georgia to

Charleston with wind gusting to hurricane force strength in the Charleston area. The highest recorded sustained wind speed was 58 mph in downtown Charleston, with gusts reaching 85 mph.

Rainfall was heavy along coastal counties as 12 inches of rain fell in Georgetown County. A reported 18 inches fell in eastern Horry County, causing major flooding along the Waccamaw River in and around the City of Conway for a month. Waves were reported to be 15 feet at Cherry Grove

Pier, where damage was the greatest. Tides exceeded three feet above normal with a maximum tidal height of 10.66 feet in the City of Charleston. Minor to moderate beach erosion occurred along the South Carolina coast. Many businesses and homes suffered major damage, with thousands of homes experiencing at least some minor damage in Charleston County, causing approximately

$10.5 million in damage. In Horry County, approximately 400 homes and numerous roads were inundated for over one month following the storm. Beaufort County reported $750,000 damage with Berkeley and Dorchester counties reporting $500,000 each. Over 1,000 trees were blown down, knocking out power to over 200,000 customers across the southern coast. In Myrtle Beach, the tree and sign damage was reported to reach approximately $250,000. In Williamsburg County, total damage estimates due to the high winds and rain reached approximately $650,000. In

Florence County, high winds downed trees, caused power outages and resulted in $150,000 in property damages. Total estimated property damages for the affected counties totaled approximately $17 million. While Hurricane Floyd did not make landfall in South Carolina, it resulted in the largest peacetime evacuation in the state’s history. It is estimated that between

500,000 and one million people evacuated the coast. South Carolina received a Presidential

Disaster Declaration for this event.



Recent Hurricane and Tropical Storm Activity

South Carolina has been affected by four hurricanes or tropical storms since 2001. These events account for three injuries and $23.42 million in property damage for the state of South Carolina

(Hazards Research Lab, 2006). Only two of these systems caused serious damage to people and property in South Carolina. Hurricane Charley hit Florida in August 2004 as a category four hurricane, but weakened as it left Florida’s east coast. Taking a northerly track, Charley made a second landfall near Cape Romain as a weak category one hurricane. Nearly 180,000 people evacuated Horry County in advance of the storm. Charley brought down trees, damaged roofs, and flooded coastal areas around the Grand Strand. More than 65,000 residents lost power and insurance claims totaling $5 million along the grand strand were reported (NCDC Storm Data

Online, 2006).

Tropical Storm Gaston impacted Berkeley, Charleston, and Dorchester Counties on August 29,

2004, causing $16.6 million dollars in property damage in Charleston and Berkeley Counties (NCDC

Storm Data Online, 2006). Gaston came ashore near Bulls Bay with sustained 70 mph winds, which knocked down numerous trees and large limbs. Major damage was reported to over 3000 structures and power loss to over 150,000 people. A storm surge of 4 to 4.5 feet caused localized flooding.

Tropical Storm Frances passed through South Carolina in early September of 2004. The state received a presidential disaster declaration for this event. Areas around Caesar’s Head and Rich

Mountain received over 12 inches of rain from the storm. According to the National Weather

Services, a reported 45 tornadoes in South Carolina were associated with this storm.

Tropical Storm Hannah made landfall on September 6, 2008, impacting Myrtle Beach and the

North Carolina-South Carolina border. Hannah brought substantial rain, strong winds, and storm surge to South Carolina.


It can be expected that future hurricane and tropical storm events will affect the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .



LIGHTNING

Background

Lightning is a discharge of electrical energy resulting from the buildup of positive and negative charges within a thunderstorm, creating a “bolt” when the buildup of charges becomes strong enough. This flash of light usually occurs within the clouds or between the clouds and the ground. A bolt of lightning can reach temperatures approaching 50,000 degrees Fahrenheit. Lightning rapidly heats the sky as it flashes but the surrounding air cools following the bolt. This rapid heating and cooling of the surrounding air causes the thunder which often accompanies lightning strikes. While most often affiliated with severe thunderstorms, lightning may also strike outside of heavy rain and might occur as far as 10 miles away from any rainfall.

According to FEMA, lightning injures an average of 300 people and kills 80 people each year in the

United States. NOAA’s National Weather Service reported 42 deaths and 58 injuries from lightning for the ten year average between 2000 and 2009. Of these, fourteen occurred in South Carolina

( Table 4.9

). Direct lightning strikes also have the ability to cause significant damage to buildings, critical facilities and infrastructure largely by igniting a fire. Lightning is also responsible for igniting wildfires that can result in widespread damages to property.

Table 4.9: Lightning Deaths in South Carolina


2000

2001

2002

2003

2

1

2

0

2004

2005

2006

2007

2008

2009

2

1

2

2

2

0

TOTAL 14



Lightning occurs randomly, in very small geographic areas. Therefore it is impossible to predict where it will strike. However, as indicated in Figure 4.4

below, lighting occurs more frequently along the coast at 8-10 cloud-to-ground lightning occurrences (flashes per square miles per year).

This then diminishes as you move further inland, leveling off at 3 to 4 flashes per square mile per year.

Figure 4.3

shows a lightning flash density map for the years 1997-2007 based upon data provided

® ). by Vaisala’s U.S. National Lightning Detection Network (NLDN



Figure 4.4: Lightning Flash Density in the United States

4:28

Source: NOAA, HRD; Vaisala U.S. National Lightning Detection Network


According to the National Climatic Data Center, there have been a total of nine 391 lightning events recorded in South Carolina since 1950.

4

Notable Lightning Events in South Carolina

August 23, 1995: The First Recruit Training Battalion, stationed on Paris Island in Beaufort

County, had been ordered to seek shelter and were walking in platoon formation toward a covered area when lightning struck, killing one soldier and injuring six others.

June 29, 1998: Three women were crossing a road in Murrells Inlet when they were struck by lightning, hospitalizing two of them.

August 16, 1998: A couple was struck by lightning near 13th hole at Colonial Charters Golf

Course in Horry County. Although the woman was successfully revived, the man died from the strike.

4 These lightning events are only inclusive of those reported by the National Climatic Data Center (NCDC). It is likely that additional lightning events have occurred in the state of South Carolina. As additional local data becomes available, this hazard profile will be amended.



August 27, 1999: Three people were hit by lightning while visiting the River Banks Zoo in

Richland County. The victims were taken to nearby hospitals and released the next day.

June 21, 2001: Lightning struck an apartment complex in Myrtle Beach, igniting a fire. Residents in the building's 14 apartments were forced to relocate after a Horry County code enforcer deemed the building uninhabitable. Damages were estimated at $20,000.

June 24, 2001: Lightning struck a transformer at a manufacturing plant in Cherokee County in the

Town of Gaffney, shutting it down for more than 24 hours. This forced shutdown resulted in approximately 1,000 employees unable to work and caused $1 million in damages.

February 22, 2003: A home was struck by lightning that caused a fire resulting in $70,000 worth of damage.

June 11, 2003: Lightning struck a home starting a fire that caused $55k in damage.

July 21, 2003: Lightning struck a home in Spring Valley at 411 Bridgecrest Drive and caused

$175,000 in damage.

August 14, 2005: Lightning caused a home fire at 204 Upland Trail that caused $300k worth of damage.

June 12, 2006: Lightning struck a tree and ran through the ground into the home starting a fire in the home in the Woodcreek Farms Subdivision.

June 11, 2009: Lightning struck a home and ignited a fire which destroyed it. The home was located at 150 Rivendale Drive. Lightning struck a home at 38 Shoreline Drive and ignited a fire which destroyed it.

July 26, 2010: WIS TV reported a home destroyed from a fire caused by lightning on Ripplerock road.

June 28, 2011: A mid-afternoon thunderstorm produced lightning that struck an Oak tree at Allen

Benedict Court on Harden Street where 5 landscape and maintenance workers were sitting. One worker was taken to the hospital with non-life threatening injuries. The others were treated and released.

Probability of Future Occurrences

It can be expected that future lightning events will continue to cause minor damages to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. According to NOAA, South Carolina experienced an average of 2-16 lightning flashes per square kilometer per year between 1997 and 2007. Coastal areas generally have a greater threat than inland areas. The specific probability for each campus can be found in

Section 5: Hazard Analysis .



SEVERE THUNDERSTORMS

Background

According to the National Weather Service, more than 100,000 thunderstorms occur each year, though only about 10 percent of these storms are classified as “severe.” A severe thunderstorm occurs when the storm produces one of three elements: 1) Hail of three-quarters of an inch; 2)

Tornado; 3) Winds of at least 58 miles per hour.

Although thunderstorms generally affect a small area when they occur, they are very dangerous because of their ability to generate tornadoes, hailstorms, strong winds, flash flooding and damaging lightning. While thunderstorms can occur in all regions of the United States, they are most common in the central and southern states because atmospheric conditions in those regions are most ideal for generating these powerful storms.

Three conditions need to occur for a thunderstorm to form. First, it needs moisture to form clouds and rain. Second, it needs unstable air, such as warm air that can rise rapidly (this often referred to as the “engine” of the storm). Third, thunderstorms need lift, which comes in the form of cold or warm fronts, sea breezes, mountains, or the sun’s heat. When these conditions occur simultaneously, air masses of varying temperatures meet, and a thunderstorm is formed. These storm events can occur singularly, in lines, or in clusters. Further, they can move through an area very quickly or linger for several hours.

Figure 4.5

illustrates thunderstorm hazard severity based on the annual average number of days with a thunderstorm event.

Figure 4.5: Average Number of Days with Thunderstorms

Source: NOAA



Straight-line Wind

Straight-line winds, which in extreme cases have the potential to cause wind gusts that exceed 100 miles per hour, are responsible for most thunderstorm wind damage. One type of straight-line wind, the downburst, can cause damage equivalent to a strong tornado and can be extremely dangerous to aviation.


Thunderstorm are atmospheric and thus occur almost anywhere. As can be seen in Figure 4.4 above, South Carolina is one of the more vulnerable states in the U.S. to thunderstorm events. A majority of state experiences 60 days with a thunderstorm event, while the most northern part experiences 50 days per year. In the southeast, thunderstorms typically occur in the afternoon, especially in the summer months. As heat and moisture builds in the atmosphere throughout the day, it needs a release for of the built-up energy resulting in a thunderstorm. Thunderstorms vary tremendously in terms of size, location, intensity and duration but are considered frequent occurrences throughout South Carolina, especially in coastal areas. It is assumed that all of the

USC campuses are exposed to severe thunderstorms.


According to the National Climatic Data Center, 7,373 thunderstorm wind events have been reported in South Carolina since 1950. Specific historical events on each campus are described in the proceeding section: Hazard Analysis .


It can be expected that future thunderstorm events will continue to cause minor damages to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in

Section 5: Hazard Analysis .



TORNADOES

Background

A tornado is a violent windstorm characterized by a twisting, funnel-shaped cloud extending to the ground. Tornadoes are most often generated by thunderstorm activity (but sometimes result from hurricanes and other tropical storms) when cool, dry air intersects and overrides a layer of warm, moist air forcing the warm air to rise rapidly. The damage caused by a tornado is a result of the high wind velocity and wind-blown debris, also accompanied by lightning or large hail. According to the National Weather Service, tornado wind speeds normally range from 40 to more than 300 miles per hour. The most violent tornadoes have rotating winds of 250 miles per hour or more and are capable of causing extreme destruction and turning normally harmless objects into deadly missiles.

Each year, an average of over 800 tornadoes is reported nationwide, resulting in an average of 80 deaths and 1,500 injuries (NOAA, 2002). The National Weather Service reported an average from

2000 to 2010 of 63 deaths annually.

Tornadoes are more likely to occur during the months of March through June and can occur at any time of day, but are likely to form in the late afternoon and early evening. Most tornadoes are a few dozen yards wide and touch down briefly, but even small short-lived tornadoes can inflict tremendous damage. Highly destructive tornadoes may carve out a path over a mile wide and several miles long.

The destruction caused by tornadoes ranges from light to inconceivable depending on the intensity, size and duration of the storm. Typically, tornadoes cause the greatest damage to structures of light construction such as residential homes (particularly mobile homes). The Fujita-Pearson Scale for Tornadoes was developed to measure tornado strength and associated damages and was used prior to 2005 ( Table 4.10

). Tornado magnitudes that were determined in 2005 and later were determined using the Enhanced Fujita Scale (Table 4.11)

Table 4.10: Fujita-Pearson Scale for Tornadoes (Effective prior to 2005)

F-SCALE

NUMBER

F0

F1

F2

F3

F4

F5

INTENSITY

PHRASE

GALE

MODERATE

SIGNIFICANT

SEVERE

DEVASTATING

INCREDIBLE

WIND SPEED

(MPH)

TYPE OF DAMAGE DONE

40

73

–

–

113

158

207

261

72

112

–

–

–

–

157

206

260

318

Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages to sign boards.

The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.

Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.

Roof and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted.

Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.

Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-enforced concrete structures badly damaged.



F6

INCONCEIVABLE 319 – 379

These winds are very unlikely. The small area of damage they might produce would probably not be recognizable along with the mess produced by F4 and F5 wind that would surround the F6 winds. Missiles, such as cars and refrigerators would do serious secondary damage that could not be directly identified as F6 damage. If this level is ever achieved, evidence for it might only be found in some manner of ground swirl pattern, for it may never be identifiable through engineering studies.

Source: The Tornado Project, 2002

Table 4.11: Fujita-Pearson Scale for Tornadoes (Effective 2005 and later)

EF-SCALE

NUMBER

F0

F1

F2

INTENSITY

PHRASE

GALE

MODERATE

3 SECOND

GUST (MPH)

TYPE OF DAMAGE DONE

65–85

86–110

SIGNIFICANT 111–135

Some damage to chimneys; breaks branches off trees; pushes over shallow-rooted trees; damages to sign boards.

The lower limit is the beginning of hurricane wind speed; peels surface off roofs; mobile homes pushed off foundations or overturned; moving autos pushed off the roads; attached garages may be destroyed.

Considerable damage. Roofs torn off frame houses; mobile homes demolished; boxcars pushed over; large trees snapped or uprooted; light object missiles generated.

F3 SEVERE 136–165

Roof and some walls torn off well-constructed houses; trains overturned; most trees in forest uprooted.

F4 DEVASTATING 166–200

Well-constructed houses leveled; structures with weak foundations blown off some distance; cars thrown and large missiles generated.

F5 INCREDIBLE Over 200

Strong frame houses lifted off foundations and carried considerable distances to disintegrate; automobile sized missiles fly through the air in excess of 100 meters; trees debarked; steel re-enforced concrete structures badly damaged.

Source: National Weather Service

According to the NOAA Storm Prediction Center (SPC), the highest concentration of tornadoes in the United States has been in Oklahoma, Texas, Kansas and Florida respectively. Although the

Great Plains region of the Central United States does favor the development of the largest and most dangerous tornadoes (earning the designation of “tornado alley”), Figure 4.6

shows tornado activity in the United States based on the number of recorded tornadoes per 1,000 square miles.

The tornadoes associated with tropical cyclones are most frequent in September and October when the incidence of tropical storm systems is greatest. This type of tornado usually occurs around the perimeter of the storm, and most often to the right and ahead of the storm path or the storm


HAZARD IDENTIFICATION 4:34 center as it comes ashore. These tornadoes commonly occur as part of large outbreaks and generally move in an easterly direction.

Figure 4.6: Tornado Activity in the United States

Source: Federal Emergency Management Agency

Waterspouts

Waterspouts are weak tornadoes that form over warm water and are most common along the Gulf

Coast and southeastern states. Waterspouts occasionally move inland, becoming tornadoes that can cause damage and injury. However, most waterspouts dissipate over the open water threatening only marine and boating interests. Typically a waterspout is weak and short-lived, and because they are so common, most go unreported unless they cause damage.


Tornadoes occur throughout the state of South Carolina. Tornadoes typically impact a relatively small area; however, events are completely random and it is not possible to predict specific areas that are more susceptible to tornado strikes over time. Therefore, it is assumed that all of South

Carolina, and thus all of the USC campuses, are exposed to this hazard.




The National Climatic Data Center reported 924 tornadoes in South Carolina between 1950 and

March 2010. During this time, it reported 56 deaths and 1,303 injuries as a result of the tornadoes.

The National Weather Service, three deaths have occurred in South Carolina between 2000 and

2009 ( Table 4.12

).

Table 4.12: Tornado Deaths in South Carolina


2000

2001

2002

2003

1

0

0

0

2004

2005

2006

2007

2008

2009

1

0

0

1

0

0

TOTAL 3


All campuses should be considered equally exposed to tornado events.


It can be expected that future tornado events will continue to cause minor damages to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5:

Hazard Analysis .



WINTER STORM AND FREEZE

Background

Severe winter storms may include snow, sleet, freezing rain, or a mix of these wintry forms of precipitation. Blizzards, the most dangerous of all winter storms, combine low temperatures, heavy snowfall, and winds of at least 35 miles per hour, reducing visibility to only a few yards. Ice storms occur when moisture falls and freezes immediately upon impact on trees, power lines, communication towers, structures, roads and other hard surfaces. Winter storms and ice storms can down trees, cause widespread power outages, damage property, and cause fatalities and injuries to human life.

A winter storm can range from a moderate snow over a period of a few hours to blizzard conditions with blinding wind-driven snow that lasts for several days. Some winter storms may be large enough to affect several States, while others may affect only a single community. Many winter storms are accompanied by low temperatures and heavy and/or blowing snow, which can severely impair visibility.

Winter storm events may include snow, sleet, freezing rain, or a mix of these wintry forms of precipitation. Sleet is a raindrop that freezes into an ice pellet formation before reaching the ground, where it usually bounces upon hitting the surface and does not stick to objects. However, sleet can accumulate like snow and cause a hazard to motorists. Freezing rain is rain that falls to the ground when the temperature is below freezing, forming a glaze of ice on roadways and other surfaces. An ice storm occurs when freezing rain falls and freezes immediately upon impact. Even small accumulations of ice can cause a significant hazard, especially on power lines, roads, and trees.

A freeze event is weather marked by low temperatures below the freezing point (zero degrees

Celsius or thirty-two degrees Fahrenheit). Freeze events are particularly dangerous as they are the second biggest killer among natural hazards (extreme heat being first). Further, agricultural production can be seriously affected when temperatures remain below the freezing point for an extended period of time, particularly in areas when vulnerable crops or livestock are located.


South Carolina’s climate varies across the state. The western portion of the state is more susceptible to winter weather and often experiences winter weather during the winter months. The eastern portion, however, is much less susceptible to winter weather, making these areas less adept in dealing with such situations. Of the planning area counties, Spartanburg, Union, and

Lancaster Counties have the highest number of reported events and damage. When such events do occur, regardless of the location, the effects will be felt over a widespread area. The effects of extreme cold temperatures will be primarily limited to the elderly and homeless populations, with occasionally minor, sporadic property damages.

Deep freezes occasionally occur in South Carolina. Typically, these events cause minimal impact outside of agricultural losses and related economic industries (including commercial nurseries).

USC does not have any agricultural programs that would be affected by deep freeze events.


The National Climatic Data Center reported 232 winter storm events in South Carolina between

1950 and March 2010 which includes winter storm, snow, freezing rain, and sleet events. Sixty-one of these events were reported in the planning area counties where USC DRU campuses reside.



These events resulted in approximately $174,230,000 (2010 dollars) in damage. It should be noted that since these are regional occurrences and reported as such, some double counting may occur.

Notable Winter Storm Events in South Carolina

February 8-11, 1973: A snowstorm of historic proportions impacted the state, leaving behind a record 24 inches of snow in some areas. Snowdrifts of up to eight inches were recorded.

Approximately 30,000 motorists were stranded on the state’s highways—many rescued by helicopter. Eight exposure-related fatalities were reported. Over 200 buildings, in addition to thousands of awnings and carports, collapsed under the weight of the snow. Property and road damages as well as the cost of snow removal and rescue operations were estimated to total approximately $30 million.

March 13, 1993: This winter storm, which possessed an extremely low atmospheric pressure, passed across South Carolina bringing damaging winds, recorded snowfalls of as much as 11.5 feet in portions of the mountains, and snow flurries on the southeast tip of the coast. Preliminary damage assessments at the time were estimated at over $22 million.

March 8, 1996: This event brought record low temperatures that caused a recorded $20 million loss to the peach crop in the upper portion of the state.

January 22-29, 2000: Low pressure rapidly deepened near the Carolina coast, wrapping abundant moisture back across the piedmont of the Carolinas. By the time snow ended, accumulations ranged from 12 to 20 inches. Due to the heavy wet snow, numerous power outages occurred and buildings collapsed. On January 29, a weakening low pressure system in the Ohio

River Valley, and a low pressure system along the Gulf Coast, coupled with arctic air across the

Carolinas, resulted in an icy mess throughout Upstate South Carolina. Precipitation, which briefly began as a light mixture of sleet and snow, quickly turned to freezing rain, resulting in a glaze 1/4 to 1/2 inch thick on exposed surfaces. Power outages were common across the region, especially in the Lower Piedmont from Abbeville to Greenwood. South Carolina requested $9.2 million in federal disaster aid to remove snow and downed trees. A total of 38 counties received a Presidential

Disaster Declaration.

There have been four severe winter events in South Carolina since 2001. These winter storms account for two fatalities, twenty-four injuries and $129.8 million in property damage (NCDC Storm

Data Online, 2006).

December 4, 2002 : An ice storm causing $100 million in property damages affected a majority of the counties in the state. Abbeville, Anderson, Cherokee, Chester, Greenville, Oconee, Pickens,

Greenwood, Laurens, Spartanburg, Union, and York Counties suffered most of the losses from this event, which included ice accumulations up to 1½ inch in some areas. Hundreds of thousands of homes were without power, many for as long as two weeks in some areas.

January 25-27, 2004: A severe winter storm affected all but five counties statewide with ice and snow. Damages to property primarily in the Pee Dee region-- Darlington, Dillon, Florence, Marion,

Marlboro, and Williamsburg Counties—were estimated at over $26 million (NCDC Storm Data

Online, 2006). Major power outages occurred due to falling limbs and many homes were without power for a week. This incident prompted the first disaster declaration in two years.

February 2004: A late winter mix affecting all of the Upstate counties and those in the northern piedmont of the state caused one fatality and almost $2 million in property damages. Total snowfall accumulation was up to 22 inches in some areas and caused one fatal vehicle accident in which thousands of people became stranded on I-77.



December 2005: A winter storm producing ice and snow in the upstate counties of Abbeville,

Anderson, Cherokee, Chester, Greenville, Laurens, Oconee, Pickens, Spartanburg, Union, and York.

This event caused almost $1.5 million in property damage due to power outages and housing unit damage from falling limbs and trees. There were four (indirect) fatalities associated with carbon monoxide poisoning due to indoor generator use in Anderson. This winter storm resulted in a

Presidential disaster declaration.


It can be expected that future winter storm and freeze events will continue to cause minor damages to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .



COASTAL EROSION

Background

Erosion is the gradual breakdown and movement of land due to both physical and chemical processes of water, wind, and general meteorological conditions. Natural, or geologic, erosion has occurred since the Earth’s formation and continues at a very slow and uniform rate each year.

There are two types of soil erosion: wind erosion and water erosion. Wind erosion can cause significant soil loss as winds blowing across sparsely vegetated or disturbed land can pick up and carry soil particles through the air, thus displacing them. Water erosion can occur over land or in streams and channels. Water erosion that takes place over land may result from raindrops, shallow sheets of water flowing off the land, or shallow surface flow, which is concentrated in low spots.

Major storms such as hurricanes may cause significant coastal erosion by combining high winds with heavy surf and storm surge.

An area’s potential for erosion is determined by four factors: soil characteristics, vegetative cover, climate or rainfall, and topography. Soils composed of a large percentage of silt and fine sand are most susceptible to erosion. As the clay and organic content of these soils increase, the potential for erosion decreases. Well-drained and well-graded gravels and gravel-sand mixtures are the least likely to erode. Coarse gravel soils are highly permeable and have a good capacity for absorption, which can prevent or delay the amount of surface runoff. Vegetative cover can reduce erosion by shielding the soil surface from falling rain, absorbing water from the soil, and slowing the velocity of runoff. Runoff is also affected by the topography of the area including size, shape and slope. The greater the slope length and gradient, the more potential an area has for erosion. Climate can affect the amount of runoff, especially the frequency, intensity and duration of rainfall and storms.

When rainstorms are frequent, intense, or of long duration, erosion risks increase. Seasonal changes in temperature and rainfall amounts define the period of highest erosion risk.

Death and injury are not associated with erosion; however, it can cause the destruction of buildings and infrastructure and represents a major threat to the local economies of communities that rely on the financial benefits of recreational areas such as rivers or beaches.


All of the coastal areas in South Carolina are susceptible to the coastal erosion hazard. These areas are subject to repeated, episodic coastal erosion events that threaten public and private property.

However, some areas, such as Myrtle Beach, replenish the sand lost to coastal erosion through renourishment projects, thus greatly reducing the effects.


The severity of coastal erosion is typically measured through a quantitative assessment of annual shoreline change for a given beach cross-section of profile (feet or meters per year) over a long period of time. Erosion rates vary as a function of shoreline type and are influenced primarily by episodic events, but can be used in land use and hazard management to define areas of critical concern. Unfortunately, there is no uniform erosion rate database or GIS data layer that defines erosion rates or such areas of critical concern for the state’s shoreline. A review of the national

Climatic Data Center does not indicate any significant erosion events that would impact USC campuses.




It can be expected that coastal erosion events will continue to occur along the coast. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .



FLOOD

Background

Flooding is the most frequent and costly natural hazard in the United States, a hazard that has caused more than 10,000 deaths since 1900. Nearly 90 percent of presidential disaster declarations result from natural events where flooding was a major component.

Floods are generally the result of excessive precipitation, and can be classified under two categories: general floods , precipitation over a given river basin for a long period of time; and flash floods, the product of heavy localized precipitation in a short time period over a given location. The severity of a flooding event is determined by the following: a combination of stream and river basin topography and physiography; precipitation and weather patterns; recent soil moisture conditions; and the degree of vegetative clearing.

General floods are usually long-term events that may last for several days. The primary types of general flooding include riverine, coastal and urban flooding. Riverine flooding is a function of excessive precipitation levels and water runoff volumes within the watershed of a stream or river.

Coastal flooding is typically a result of storm surge, wind-driven waves and heavy rainfall produced by hurricanes, tropical storms and other large coastal storms. Urban flooding occurs where manmade development has obstructed the natural flow of water and decreased the ability of natural groundcover to absorb and retain surface water runoff.

Most flash flooding is caused by slow-moving thunderstorms in a local area or by heavy rains associated with hurricanes and tropical storms. However, flash flooding events may also occur from a dam or levee failure within minutes or hours of heavy amounts of rainfall, or from a sudden release of water held by a retention basin or other stormwater control facility. Although flash flooding occurs most often along mountain streams, it is also common in urbanized areas where much of the ground is covered by impervious surfaces. Flash flood waters move at very high speeds—“walls” of water can reach heights of 10 to 20 feet. Flash flood waters and the accompanying debris can uproot trees, roll boulders, destroy buildings, and obliterate bridges and roads.

The periodic flooding of lands adjacent to rivers, streams and shorelines (land known as floodplain) is a natural and inevitable occurrence that can be expected to take place based upon established recurrence intervals. The recurrence interval of a flood is defined as the average time interval, in years, expected between a flood event of a particular magnitude and an equal or larger flood. Flood magnitude increases with increasing recurrence interval.

Floodplains are designated by the frequency of the flood that is large enough to cover them. For example, the 10-year floodplain will be covered by the 10-year flood and the 100-year floodplain by the 100-year flood. Flood frequencies such as the 100-year flood are determined by plotting a graph of the size of all known floods for an area and determining how often floods of a particular size occur. Another way of expressing the flood frequency is the chance of occurrence in a given year, which is the percentage of the probability of flooding each year. For example, the 100-year flood has a 1 percent chance of occurring in any given year. The 500-year flood has a 0.2 percent chance of occurring in any given year.


Several areas throughout the state of South Carolina are subject to flooding. Location varies substantially by campus and is discussed extensively in Section 5: Hazard Analysis using maps and narrative. In addition to riverine flooding, areas closer to the coast general are very flat and close


HAZARD IDENTIFICATION 4:42 to sea level. This results in extensive “ponding” due to the lack of elevation gradients to facilitate adequate stormwater runoff. Further, its water supply lies just below the surface of the ground.

Regardless of the location, major rainfall events sometimes leave rainwater nowhere to drain, causing flooding near rivers and canals as well as in urban areas due to poor percolation rates and the low elevations (particularly in western parts of the county). Coastal flooding along the shoreline is typically associated with tidal surge caused by land-falling tropical storms and hurricane events.


According to the National Climatic Data Center, there have been 777 reported flood events throughout the State between 1950 and March 2010. Of these, 215 occurred in the planning area counties where USC campuses reside. These events accounted for nearly $108 million (2010 dollars) in damages. Obviously this makes flooding a frequent and costly hazard for the state.

Of the flood events recorded, six events are considered notable based on the following criteria: extent, number of deaths, and amount of property damage sustained. Prior to 1993, four particular floods in the 20th century are remembered for causing numerous deaths, significant property damage, and/or Presidential Disaster Declarations.

The following information highlights flood events that are detailed in the state hazard mitigation plan.

June 6, 1903 (“The Great Pacolet Flood”): “The Great Pacolet Flood” of 1903 resulted in the greatest loss of life from riverine flooding during the 20th century in the state. Sixty-five (65) people drowned. According to a National Weather Service Monthly Weather Review report, the water rose so rapidly that the land near the river was covered by 41 feet of water within 40 minutes. Homes, churches and businesses, including 7 cotton mills, 13 railroad bridges, and 17 farm houses were destroyed. 4,300 people were put out of work due to the flood. Railway traffic was disrupted and the textile communities of Pacolet in Spartanburg County and Clinton in Laurens

County were devastated by this event. Flood damages were also reported along other streams in the northwestern section of the state. Damages were estimated to be approximately $3,866,000.

August 26–30, 1908 (Riverine Flooding): This storm event formed in the Gulf of Mexico and moved slowly northeastward across the state. This event is considered to be the most extensive flood in South Carolina on record, as all the major rivers in the state exceeded flood stage by between nine and 22 feet. Heavy damages to property and crops were reported.

September 21–24, 1928 (Riverine and Coastal Flooding): This flood event was caused by an unnamed hurricane. Severe flooding was reported statewide, with rainfall totals ranging from 10 to

12 inches. Many bridges were destroyed, and roads and railways were impassable. Property losses reached an estimated $4 to $6 million.

October 22, 1990 (Severe Storm Flooding): The worst riverine flooding in recent times occurred in October 1990 as a result of rains from Tropical Storms Klaus and Marco. Eleven of the state’s fifteen river basins exceeded flood stage. Within a 24-hour period, areas in Orangeburg,

Sumter, Kershaw, Lancaster, and Chesterfield counties experienced as much as 10-15 inches of rain, which exceeded the 50-100 year events. This flood event resulted in a Presidential Disaster

Declaration (DR-881) for 13 counties in South Carolina, including Aiken, Calhoun, Cherokee,

Darlington, Edgefield, Florence, Kershaw, Lancaster, Lee, Orangeburg, Spartanburg, Sumter and

Union.

April 5, 1993 (Coastal Flooding): The northeast coastal beaches experienced a combination of high spring tides and strong onshore winds on this date, causing considerable beach erosion and coastal flooding. Many dune crossovers, walkways, and staircases were destroyed in the Myrtle-



Crescent Beach area in Horry County. North Myrtle Beach lost three to four feet of dunes. Property damages, totaling $7,716,247 based on current cost estimates, were reported.

June 27, 1994 (Flash Flooding): Within a 24-hour period, heavy rain caused flash flooding in portions of central South Carolina. Severe flash flooding in Lexington County flooded roadways and culverts, and breached a millpond dam on Red Bank Creek that resulted in two additional downstream dam failures. Approximately $7,330,363 in current estimated property damages occurred, primarily along Red Bank Creek and Congaree Creek, as floodwaters washed trees and other debris into sheds, homes, and vehicles. Two people were rescued when the car they were riding in was swept off of Highway 6 near Red Bank Creek, shortly after the failure of Red Bank Mill

Dam.

October 3, 1994 (Coastal and Flash Flooding): Record-breaking rainstorms, with unofficially recorded rainfall exceeding 13 inches within 24-hour period in Beaufort County, impacted the

South Carolina coast. A 24-hour rain total of 11.5 inches was recorded at Honey Horn Plantation, located on northern Hilton Head Island. This rainfall event broke the official all-time rainfall record at that location. There were also scattered areas of flash flooding in the county, followed by severe coastal flooding. Heaviest flooding was reported on Hilton Head Island. Floodwaters covered many streets, damaged more than 147 homes, six government buildings, 36 businesses and at least 45 cars. Approximately 37 roads washed out or were damaged. The area’s oyster beds were closed from October 3 to October 24 due to effluent releases. Several Low Country sewage treatment plants reported flooding problems and more than 3,012 consumers lost electrical power. Based on current cost estimations, $1,466,073 in property damages was reported. In Colleton County,

$1,466,073 in property damages (based on current cost estimations) was reported when roads flooded and numerous homes were damaged by the floodwaters. Rainfall amounts of four to eight inches fell within a 24-hour period across much of Charleston County. Runoff from heavy rains, high tides and strong winds caused significant flooding over much of the coastal areas of the county, especially in the City of Charleston and over most of the nearby barrier islands. Buildings and homes were damaged, sewers backed up, roads flooded, and cars were inundated by the floodwaters.

The county experienced $439,822 in property damages and $8,796 in crop damages, based on current cost estimates. There was an additional $73,304 in property damages reported due to flash flooding.

October 13, 1994 (Flash and Coastal Flooding): Bands of heavy precipitation produced four to

10 inches of rain along the South Carolina coast, causing varying degrees of flash flooding in 40 counties. Flash flooding caused $2,932,000 in property damages and $11,720 in crop damages, based on current dollar estimations. The heaviest rainfall and the worst flooding occurred in

Charleston, southern Colleton County, Beaufort County and southern Jasper County. Numerous roads were flooded and/or washed away. There was considerable flooding of homes and businesses throughout the area. Beach erosion was also noted at several locations along the South Carolina coast. Beaufort County was heavily impacted, reporting 218 homes/villas/apartments damaged or destroyed. Fifteen businesses reported flood damage. Eight wastewater treatment plants and two golf courses were heavily damaged. Moderate beach erosion was reported along the south coast, with 200,000 cubic yards of sand lost on Hilton Head Island. Coastal flooding caused $36,651,824 in property damages and $73,260 in crop damages based on current dollar estimates.

August 24–31, 1995 (Flooding and Flash Flooding): Slow moving bands of heavy rain, formed from remnants of Tropical Storm Jerry, began moving into South Carolina, dumping an initial three to five inches of rain. As additional bands moved across the state, flash flooding developed in various areas and roads became flooded and impassable. Approximately 11 inches fell within a 48hour period in Abbeville County, washing out bridges and closing roads. Flooding from the heavy rains disrupted traffic on Hilton Head Island and St. Helena Island, covering roads and bridges and flooding some homes. Already saturated ground produced flash flooding in some areas, as well as


HAZARD IDENTIFICATION 4:44 flooding in areas where flash flooding had occurred earlier. As rivers and creeks continued to rise, at least six bridges were destroyed in Laurens County, including the Highway 418 Bridge across the

Enoree River. Several small dams broke, including one in Union County where a wall of water rushed across a road. Throughout much of eastside of Greenville, Greer, Taylors, and the western side of Spartanburg, storm water totals of approximately 15 inches were reported. Two deaths were reported in the Greenville-Spartanburg area and one death was reported in Gaffney. Flooding along the Enoree River, Abner Creek, Brushy Creek, Gilder Creek, and Horseman Creek in the eastern half of Greenville and the western side of Spartanburg County was the worst in recent memory. The South Carolina Department of Transportation estimated between $4 and $5 million in damages to roads and bridges. The current total cost estimates for the damages caused by this extended flood event equal $18,717,472.

August 14–15, 1998 (Flash Flooding): A flash flood in Spartanburg County rapidly developed following four to five inches of rainfall, which fell during a very short time period. The flash flooding affected several creeks around the City of Spartanburg and moved southward to Roebuck, Walnut

Grove and Pauline. Most of the damages occurred along Timms Creek and Lawson Fork Creek.

Roads were washed out and several people had to be rescued from their homes. A country club experienced severe damage and a restaurant was destroyed. Property damages of $3,145,092, based on current cost estimates, were reported. For a second consecutive night, on August 15, a flash flood occurred in Spartanburg County. The primary flooding occurred along Fairforest Creek and affected the communities located on the west side of the city. An area motel was flooded, requiring the evacuation of the residents. This second flood event caused additional property damages of $629,018, based on current cost estimates.

Recent Flood Activity

Five flood events have occurred in the state since 2001 that are considered significant events

(causing more than $1 million in property or crop damage). The first event was the Greater

Greenville flood of March 20, 2003 , which caused $1.3 million in property damage in Greenville and over $1.0 million in Spartanburg. Heavy overnight rainfall produced flash flooding, and continued moderate rainfall resulted in additional flooding along many creeks and streams in areas of Greenville County. The flooding was quite significant in Berea, Taylors, and Mauldin. In Berea, some residents had to be rescued via canoe from their homes (NCDC Storm Data Reports Online).

Another flood event caused by heavy rainfall occurred on September 7, 2004 in Oconee and

Greenville counties causing an estimated $2.6 million in property damage and $5 million in crop damage. Widespread flooding of creeks and streams developed across the two counties. Numerous roads were covered with water or washed out, and the sewer systems of several communities were damaged.

Another large flash-flooding event hit Greenville on July 29, 2004 causing $3.5 million in property damage. A nearly stationary thunderstorm produced 4 to 9 inches of rainfall in approximately 4 hours resulting in major flooding in areas from Berea to downtown Greenville. The Reedy River crested at 19.2 feet in downtown Greenville, the second highest level on record (NCDC Storm Data reports Online, 2006). Several businesses and homes along the river incurred major damage, hundreds of vehicles were damaged or destroyed, and numerous roads and bridges were damaged or washed out. At least 30 homes were condemned (NCDC Storm Data Reports, 2006).

A flash flood on July 7, 2005 in Greenville, Pickens, and Spartanburg Counties caused $1.8 million in property damage as more than thirty homes were inundated by floodwaters. More than 100 people had to be rescued from various locations throughout these counties as floodwaters washed out roadways and bridges across the three counties.



The most recent flood event occurred on August 10, 2005 and caused $1.5 million in property damage when a pond overflowed into a new subdivision in Spartanburg County, affecting fifteen new homes.


It can be expected that future flooding events will cause damage to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .



STORM SURGE

Background

Storm surge occurs when the water level of a tidally influenced body of water increases above the normal astronomical high tide, and are most common in conjunction with coastal storms with massive low-pressure systems with cyclonic flows such as hurricanes, tropical storms and nor’easters. The low barometric pressure associated with these storms cause the water surface to rise, and storms making landfall during peak tides have surge heights and more extensive flood inundation limits. Storm surges will inundate coastal floodplains by dune overwash, tidal elevation rise in inland bays and harbors, and backwater flooding through coastal river mouths. The duration of a storm is the most influential factor affecting the severity and impact of storm surges.

A storm surge is often described as a wave that has outrun its generating source and become a long period swell. It is often recognized as a large dome of water that may be 50 to 100 miles wide and generally rising anywhere from four to five feet in a Category 1 hurricane to over 20 feet in a Category 5 storm. The storm surge arrives ahead of the storm center’s actual landfall and the more intense the storm is, the sooner the surge arrives. Water rise can be very rapid, posing a serious threat to those who have not yet evacuated flood-prone areas. The surge is always highest in the right-front quadrant of the direction in which the storm is moving. As the storm approaches shore, the greatest storm surge will be to the north of the low-pressure system or hurricane eye.

Such a surge of high water topped by waves driven by hurricane force winds can be devastating to coastal regions, causing severe beach erosion and property damage along the immediate shoreline.

Storm surge heights and associated waves are dependent on not only the storm’s intensity but also upon the shape of the offshore continental shelf (narrow or wide) and the depth of the ocean bottom (bathymetry). A narrow shelf, or one that drops steeply from the shoreline and subsequently produces deep water close to the shoreline, tends to produce a lower surge but higher and more powerful storm waves. The storms that generate the largest coastal storm surges can develop year-round, but they are most frequent from late summer to early spring.


Areas along coasts, bays, inlets, and lakes are at risk to storm surge. The USC campuses located in coastal areas (Baruch and Beaufort) were analyzed for surge risk. Specific information on the locations at risk can be found in Section 5: Hazard Analysis .


The National Climatic Data Center reported just 18 events for storm surge events in the state from

1995 to March 2010. Just one of these occurred in a planning area county (Aiken County), which does not pertain to coastal storm surge. However, hurricane and tropical storm events result in surge and it is known hazard in the state. Specific historical occurrences are detailed for coastal campuses in Section 5: Hazard Analysis .


It can be expected that future coastal storm surge events will cause damage to property and coastal erosion along coastal areas in the state. Probability will vary by location; therefore, an analysis of each campus is performed and can be found in Section 5: Hazard Analysis .



EARTHQUAKES

Background

An earthquake is movement or trembling of the ground produced by sudden displacement of rock in the Earth's crust. Earthquakes result from crustal strain, volcanism, landslides or the collapse of caverns. Earthquakes can affect hundreds of thousands of square miles, cause damage to property measured in the tens of billions of dollars, result in loss of life and injury to hundreds of thousands of persons; and disrupt the social and economic functioning of the affected area.

Most property damage and earthquake-related deaths are caused by the failure and collapse of structures due to ground shaking. The level of damage depends upon the amplitude and duration of the shaking, which are directly related to the earthquake size, distance from the fault, site and regional geology. Other damaging earthquake effects include landslides, the down-slope movement of soil and rock (mountain regions and along hillsides), and liquefaction, in which ground soil loses the ability to resist shear and flows much like quick sand. In the case of liquefaction, anything relying on the substrata for support can shift, tilt, rupture or collapse.

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. These fault planes are typically found along borders of the Earth's 10 tectonic plates. The areas of greatest tectonic instability occur at the perimeters of the slowly moving plates, as these locations are subjected to the greatest strains from plates traveling in opposite directions and at different speeds. Deformation along plate boundaries causes strain in the rock and the consequent buildup of stored energy. When the builtup stress exceeds the rocks' strength, a rupture occurs. The rock on both sides of the fracture is snapped, releasing the stored energy and producing seismic waves, generating an earthquake.

Earthquakes are measured in terms of their magnitude and intensity. Magnitude is measured using the Richter Scale, an open-ended logarithmic scale that describes the energy release of an earthquake through a measure of shock wave amplitude ( Table 4.13

). Each unit increase in magnitude on the Richter Scale corresponds to a 10-fold increase in wave amplitude, or a 32-fold increase in energy. Intensity is most commonly measured using the Modified Mercalli Intensity

(MMI) Scale based on direct and indirect measurements of seismic effects. The scale levels are typically described using roman numerals, with a I corresponding to imperceptible (instrumental) events, IV corresponding to moderate (felt by people awake), to XII for catastrophic (total destruction). A detailed description of the Modified Mercalli Intensity Scale of earthquake intensity and its correspondence to the Richter Scale is given in Table 4.14

.



Table 4.13: Richter Scale

RICHTER

MAGNITUDES

< 3.5

3.5 - 5.4

5.4 - 6.0

6.1 - 6.9

7.0 - 7.9

EARTHQUAKE EFFECTS

Generally not felt, but recorded.

Often felt, but rarely causes damage.

At most slight damage to well-designed buildings. Can cause major damage to poorly constructed buildings over small regions.

Can be destructive in areas up to about 100 kilometers across where people live.

Major earthquake. Can cause serious damage over larger areas.

8 or > Great earthquake. Can cause serious damage in areas several hundred kilometers across.


Table 4.14: Modified Mercalli Intensity Scale for Earthquakes

SCALE

I

INTENSITY DESCRIPTION OF EFFECTS

INSTRUMENTAL Detected only on seismographs.

CORRESPONDING

RICHTER

MAGNITUDE

SCALE

II

III

FEEBLE

SLIGHT

Some people feel it.

Felt by people resting; like a truck rumbling by.

IV

V

MODERATE

SLIGHTLY

STRONG

Felt by people walking.

Sleepers awake; church bells ring.

VI STRONG

Trees sway; suspended objects swing, objects fall off shelves.

VII VERY STRONG Mild alarm; walls crack; plaster falls.

VIII

IX

X

XI

XII

DESTRUCTIVE

RUINOUS

DISASTROUS

VERY

DISASTROUS

CATASTROPHIC

Moving cars uncontrollable; masonry fractures, poorly constructed buildings damaged.

Some houses collapse; ground cracks; pipes break open.

Ground cracks profusely; many buildings destroyed; liquefaction and landslides widespread.

Most buildings and bridges collapse; roads, railways, pipes and cables destroyed; general triggering of other hazards.

Total destruction; trees fall; ground rises and falls in waves.


< 4.2

< 4.8

< 5.4

< 6.1

< 6.9

< 7.3

< 8.1

> 8.1




The greatest earthquake threat in the United States is along tectonic plate boundaries and seismic fault lines located in the central and western states; however, the East Coast does face moderate risk to less frequent, less intense earthquake events. Figure 4.7

shows relative seismic risk for the

United States, which indicates that the state falls between 4 percent g and 24 percent g. (Percent g refers to the percentage of gravity which is a measure of the forces caused by the earthquake shaking.)

Figure 4.7: United States Earthquake Hazard Map

Source: United States Geological Survey



Figure 4.8

shows major historic earthquake epicenters (magnitude 3.0 or greater on the Richter

Scale) within the state.

5

Figure 4.8: Seismic Hazard Map for South Carolina

Source: United States Geological Survey

5

Figure references earthquake magnitudes up to 6.9 on the Richter Scale based on information provided by the University of

South Carolina Seismic Network. Some other official records classify the 1886 Charleston earthquake as up to a 7.3 magnitude event instead of a 6.9 magnitude event. Date of occurrence is listed Universal Coordinated Time.



Figure 4.9

shows the fault lines in South Carolina.

Figure 4.9: Fault Lines in South Carolina

4:51

Source: http://www.dnr.sc.gov/geology/earthquake.htm

6


The National Geophysical Data Center has 1,086 data records of earthquake activity in the State of

South Carolina from December 16, 1811 through

June 9, 1985. During this time period, the

Modified Mercalli Scale Intensity (given in Roman

Numeral values) of these events ranged from a II up to an X in intensity. (To help put this scale into perspective, the devastating Charleston earthquake of 1886 was a X.) An earthquake with a Modified Mercalli Scale Intensity (MMI) of VI or greater is likely to cause structural damages, injuries and possible deaths. Events that affected each county where a USC campus is located are described in the Section 5: Hazard Analysis .

According to the National Geophysical Data Center, only one significant earthquake has occurred in

South Carolina - the Charleston Earthquake of

Photo from the Earth Science Photographs - U.S.

Geological Survey Library. Joseph K. McGregor and Carl Abston. U.S. Geological Survey Digital

Data Series DDS-21, 1995.

6 Maybin, A.H., Clendenin, C.W., Jr., Assisted by Daniels, D.L., 1998, Structural features map of South Carolina: South

Carolina Geological Survey General Geologic Map Series, 1p.



1886. During this event, Horry County experienced a magnitude of VI (Strong) on the Modified

Mercalli Intensity (MMI) Scale. There have been more than two hundred minimal earthquakes reported in South Carolina since 2001, but none of these events caused any significant damage and many were not even strong enough to be felt by people.

Charleston Earthquake

On August 31, 1886, an earthquake occurred in Charleston, South Carolina that is considered to be one of the most damaging earthquakes to occur in the southeast United States. This earthquake killed 60 people and left most structures in the Charleston area damaged or destroyed, resulting in an estimated $23 million 7 in damage. Although Charleston and the cities and towns nearby suffered most of the damage, cities located as far away as Georgia and North Carolina were affected. According to the U.S. Geological Survey (USGS), “The total area affected by this earthquake covered more than five million square kilometers and included distant points such as

New York City, Boston and Milwaukee in the United States, and Havana, Cuba and Bermuda. All or parts of 30 states and Ontario, Canada, felt the principal earthquake.”

Recent Earthquake Activity

There have been more than two hundred minimal earthquakes in South Carolina since 2001. None of these events caused any significant damage and many were not even strong enough to be felt by people. There have been no significant earthquakes during this time period. The counties that have had the greatest number of earthquakes during this time period are Fairfield County and

Berkeley County with one hundred thirty-four and forty-one earthquakes respectively (South

Carolina Seismic Network, 2006).


It can be expected that future earthquake events will cause minor damage to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. The specific probability for each campus can be found in Section 5: Hazard Analysis .

7 Other sources quote South Carolina damages for this event at $5.5 million.



SEA LEVEL RISE

Background

Sea Level Rise is defined by NOAA as the mean rise in sea level. It is caused by two factors: 1) as the ocean warms, sea water expands in volume; 2) continental ice shelves melt, increasing the amount of water in the oceans. This leads to a greater area of land being inundated by sea water.

Rising sea level contributes to the loss of coastal wetlands (which provide protective buffers from flood events), beach erosion, population and property in low areas, coastal habitats and species.

Further, flooding and hurricane events are more severe and affect a greater area.

Given that 600 million people live in an area that is less that 10 meters (33 feet) above sea level, and the coastal population has doubled in the last 50 years, sea level rise is a formidable threat.


Sea level rise is occurring along coasts across the globe. However, it does not affect areas uniformly and will be more severe in some places. Figure 4.10

shows a hypothetical situation of sea level rise where the sea rises at 1.0, 2.0, 4.0 and 8.0 meters. This research comes from NOAA.

As can be seen, sea level rise affects the South Carolina coast in each scenario. In Section 5, maps depict sea level rise scenarios along the coastal USC DRU campus counties.



Figure 4.10: Sea Level Rise in the Southeastern United States

4:54

Source: http://www.www.gfdl.noaa.gov/~tk/climate_dynamics/climate_impact_webpage.html


Sea-level rise is a slow-onset hazard that has recently been realized. No historical occurrences have been reported in the state.


There is still much debate regarding the probability of future occurrence of sea level rise.



WILDFIRE

Background

A wildfire is any fire occurring in a wildland area (i.e. grassland, forest, brush land) except for fire under prescription.

8 Wildfires are part of the natural management of forest ecosystems, but may also be caused by human factors. Over 80 percent of forest fires are started by negligent human behavior such as smoking in wooded areas or improperly extinguishing campfires. The second most common cause for wildfire is lightning.

There are three classes of wildland fires: surface fire, ground fire and crown fire. A surface fire is the most common of these three classes and burns along the floor of a forest, moving slowly and killing or damaging trees. A ground fire (muck fire) is usually started by lightning or human carelessness and burns on or below the forest floor. Crown fires spread rapidly by wind and move quickly by jumping along the tops of trees. Wildland fires are usually signaled by dense smoke that fills the area for miles around.

State and local governments can impose fire safety regulations on home sites and developments to help curb wildfire. Land treatment measures such as fire access roads, water storage, helipads, safety zones, buffers, firebreaks, fuel breaks and fuel management can be designed as part of an overall fire defense system to aid in fire control. Fuel management, prescribed burning and cooperative land management planning can also be encouraged to reduce fire hazards.

Fire probability depends on local weather conditions, outdoor activities such as camping, debris burning, and construction, and the degree of public cooperation with fire prevention measures.

Drought conditions and other natural hazards (such as tornadoes, hurricanes, etc.) increase the probability of wildfires by producing fuel in both urban and rural settings. Forest damage from hurricanes and tornadoes may also block interior access roads and fire breaks, pull down overhead power lines, or damage pavement and underground utilities.

Many individual homes and cabins, subdivisions, resorts, recreational areas, organizational camps, businesses and industries are located within high wildfire hazard areas. The increasing demand for outdoor recreation places more people in wildlands during holidays, weekends and vacation periods. Unfortunately, wildland residents and visitors are rarely educated or prepared for wildfire events that can sweep through the brush and timber and destroy property within minutes.


Wildfires are a substantial threat in South Carolina. The South Carolina Forestry Commission reports that it responds to over 3,000 fires annually. Essentially all areas are susceptible to wildfire, though highly developed areas have a fairly low risk. Wildland and areas on the wildlandurban fringe are at the greatest risk. Drought conditions can make a fire more likely in these locations and exacerbate the severity of the fire.

Future wildfires could pose interruptions to ongoing research efforts that draw in outside area for laboratory experiments. Human respiratory health is another related concern with regard to wildfires occurring nearby the USC campuses.

8 Prescription burning, or “controlled burn,” undertaken by land management agencies is the process of igniting fires under selected conditions, in accordance with strict parameters.




Data was provided from the South Carolina Forestry Commission. There are 13.6 million acres of forestland in the State of which 12.2 is commercial forestland. The Forestry Commission responds to more than 3,000 wildland fires each year which typically burn around 20,000 acres in all. Most of these fires (98%) are caused by human activity such as debris burning, arson, and camp fires.

The Forestry Commission also provided specific data of fires and acres burned for the Counties where a USC campus resides between 1946 and 2009, a 63 year period. Nearly 78,000 fires burned a combined 700,375 acres for the subject counties. This averages to 1,251 fires annually burning a combined average of approximately 11,117 acres. Specific events by county and that impacting the campuses are reported in Section 5: Hazard Analysis.


It can be expected that future wildfire events will occur in the proximately of USC campuses and cause minor damage to property and vehicles throughout the state. Probability will vary by campus location; thus an analysis of each campus is performed. Several factors influence probability including climate and surrounding groundcover. In most cases wildfires can be contained that greatest externality will be the secondary effects of smoke and ash in the air. The specific probability for each campus can be found in Section 5: Hazard Analysis .
