SWCC DRU Plan Literature Review Summary 12132012
Literature Review Summary SWCC
Southwest Virginia Community College Disaster Resistant University Plan Literature Review Summary
A hazard is an act or phenomenon that has the potential to produce harm or other undesirable consequences to persons, structures, or infrastructure. Hazards exist with or without the presence of people and land development. Some hazards such as earthquakes and tornadoes have been occurring for a very long time, and the natural environment has adapted to their impacts. When severe hazards coincide with vulnerable development, disasters can occur.
Hazard identification is the process of identifying hazards that threaten the college. Weather events are not hazards, but may cause them. For example, a summer storm may cause straight- line wind, hail, lightning, or a flood.
Risk Assessment
The first step in a risk assessment is to identify hazards that threaten or may occur. We used multiple methods to obtain hazard information. Specifically, we:
● Reviewed existing plans and reports. ● Researched newspapers and other historical records about disaster events. ● Talked to weather service and other experts in the Commonwealth and region. ● Conducted Internet searches to gather information about hazards.
The Federal Emergency Management Agency (FEMA) publishes a list of natural hazards to consider in mitigation planning. Drawn from that list, the following hazards constitute some obvious risk to be further investigated and analyzed; hazards that are likely to affect the college; and, hazards that are of no significance and will not be considered in the mitigation plan.
Dam Failure Disease Outbreak Drought Earthquake Floods Hazardous Materials Karst Topography Landslides and Debris Flow Space Weather Wind Storm Winter Storm
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Table of Contents
Dam Failure ...... 5 Disease Outbreak ...... 7 Drought ...... 11 Earthquake ...... 15 Flood and Flash Flood ...... 23 Hazardous Materials ...... 25 Karst Terrain ...... 27 Landslides and Debris Flow ...... 29 Space Weather ...... 31 Tornadoes ...... 33 Wildfire ...... 35 Wind and Severe Thunderstorms ...... 37 Winter Storm ...... 39 Recommended Approach and Methods for Vulnerability Assessment ...... 41
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Dam Failure
Dam failures involve unintended releases or surges of impounded water resulting in downstream flooding. The high velocity, debris-laden wall of water released from dam failures results in the potential for human causalities, economic loss, lifeline disruption, and environmental damage. Although they may involve the total collapse of a dam, that is not always the case as damaged spillways, overtopping from prolonged rainfall, or other problems, including the unintended consequences from normal operations, may result in a hazardous situation being created. Due to the lack of advance warning, failures from natural events, such as earthquakes, or landslides, may be particularly severe.
Dam failures may be caused by a variety of natural events, human-caused events, or a combination thereof. Dam failures usually occur when the spillway capacity is inadequate and water overtops the dam or when internal erosion through the dam foundation occurs, also known as piping. Structural deficiencies from poor initial design or construction, lack of maintenance or repair, or the gradual weakening of the dam through the normal aging process are factors contributing to dam failure events.
In general, the warning time for dam failure can vary from none to days, depending on the nature of the dam failure. There may be little or no warning time available due to failure from a catastrophic earthquake, landslide, or other natural event. In the event of flash flooding, the warning time may also be short. The most common cause of dam failure, periods of prolonged rainfall and associated flooding, generally provide the most opportunity for advance warning. Warning times may be as short as several hours, but typically extend to days.
The only dam in the area of the Southwest Community College is the Laurel Bed Lake Dam which is about 3 ½ miles south of the Southwest Community College. The lake and dam is on the far side of the Mountain Ridge in the Clinch Mountain State Wildlife Management Area, and were there to be a problem with the dam, the terrain will channel all flow to the southwest of the dam away from the Community College. There have been no dam failure incidents affecting the college.
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Laurel Bed Lake. Credit: Google Maps
We obtained this information from the Regional Engineer for Dam Safety, Virginia Department of Conservation and Recreation, Dam Safety and Floodplain Management based in Christiansburg, Virginia.
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Disease Outbreak
A disease is a pathological (unhealthy or ill) condition of a living organism or part of the organism that is characterized by an identifiable group of symptoms or signs. Disease can affect any living organism, including people, animals, and plants. Disease can both directly (via infection) and indirectly (via secondary impacts) harm these living things. Some infections can cause disease in both people and animals. The major concern here is an epidemic, a disease that affects an unexpected number of people or sentinel animals at one time. (Note: an epidemic can result from even one case of illness if that illness is unheard of in the affected population, i.e., smallpox)
Of great concern for human health are infectious diseases caused by the entry and growth of microorganisms in man. Most, but not all, infectious diseases are communicable. They can be spread by coming into direct contact with someone infected with the disease, someone in a carrier state who is not sick at the time, or another living organism that carries the pathogen. Disease-producing organisms can also be spread by indirect contact with something a contagious person or other carrier has touched and contaminated, like a tissue or doorknob, or another medium (e.g., water, air).
According to the Centers for Disease Control and Prevention (CDC), during the first half of the twentieth century, optimism grew as steady progress was made against infectious diseases in humans via improved water quality and sanitation, antibiotics, and inoculations (October 1998). The incidences and severity of infectious diseases such as tuberculosis, typhoid fever, smallpox, polio, whooping cough, and diphtheria were all significantly reduced during this period. This optimism proved premature, however, for a variety of reasons, including the following: antibiotics began to lose their effectiveness against infectious disease (e.g., Staphylococcus aureus); new strains of influenza emerged in China and spread rapidly around the globe; sexually transmitted diseases resurged; new diseases were identified in the U.S. and elsewhere (e.g., Legionnaires’ disease, Lyme disease, toxic shock syndrome, and Ebola hemorrhagic fever); acquired immunodeficiency syndrome (AIDS) appeared; and tuberculosis (including multidrug- resistant strains) reemerged (CDC, October 1998).
In a 1992 report titled Emerging Infections: Microbial Threats to Health in the United States, the Institute of Medicine (IOM) identified the growing links between U.S. and international health, and concluded that emerging infections are a major and growing threat to U.S. health. An emerging infectious disease is one that has newly appeared in a population or that has been known for some time, but is rapidly increasing in incidence or geographical range. Emerging infectious diseases are a product of modern demographic and environmental conditions, such as global travel, globalization and centralized processing of the food supply, population growth and increased urbanization.
In response to the threat of emerging infectious diseases, the CDC launched a national effort to protect the U.S. public in a plan titled Addressing Emerging Infectious Disease Threats. Based on the CDC’s plan, major improvements to the U.S. health system have been implemented, including improvements in surveillance, applied research, public health infrastructure, and prevention of emerging infectious diseases.
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Despite these improvements, infectious diseases are the leading cause of death in humans worldwide and the third leading cause of death in humans in the U.S. (American Society for Microbiology, June 21, 1999). A recent follow-up report from the IOM, titled Microbial Threats to Health: Emergence, Detection, and Response, notes that the impact of infectious diseases on the U.S. has only grown in the last ten years and that public health and medical communities remain inadequately prepared. Further improvements are necessary to prevent, detect, and control emerging, as well as resurging, microbial threats to health. The dangers posed by infectious diseases are compounded by other important trends: the continuing increase in antimicrobial resistance; the diminished capacity of the U.S. to recognize and respond to microbial threats; and the intentional use of biological agents to do harm (IOM, 2003).
The five diseases with the highest 5 year average of occurrence in Virginia (2007-2011) are Chlamydia (28,303.4), Influenza (18,436.8), Gonorrhea (7,653.8), Chickenpox (1270.2), and Salmonellosis (1161.8).
Credit: Virginia Department of Health
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Credit: Virginia Department of Health
In 2011, the rates of the above diseases per 100.000 population in the Southwest Region Health District where SWCC is located were 343.4, 381.0, 60.7, 5.7, and 14.2 respectively.
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Credit: Virginia Department of Health
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Drought
Drought is a normal, recurrent feature of virtually all climatic zones, including areas of both high and low rainfall, although characteristics will vary significantly from one region to another. It differs from normal aridity, which is a permanent feature of the climate in areas of low rainfall. Drought is the result of a natural decline in the expected precipitation over an extended period of time, typically one or more seasons in length. Other climatic characteristics, such as high temperature, high wind, and low relative humidity, impact the severity of drought conditions.
Drought can be defined using both conceptual and operational definitions. Conceptual definitions of drought are often utilized to assist in the widespread understanding of drought. Many conceptual definitions portray drought as a protracted period of deficient precipitation resulting in extensive damage to agricultural crops and the consequential economic losses occurring. Operational definitions define the beginning, end, and degree of severity of drought. These definitions are often used to analyze drought frequency, severity, and duration for given periods of time. Such definitions often require extensive weather data on hourly, daily, monthly, or other time scales and are utilized to provide a greater understanding of drought from a regional perspective. Four common definitions for drought are provided as follows:
● Meteorological drought is defined solely on the degree of dryness, expressed as a departure of actual precipitation from an expected average or normal amount based on monthly, seasonal, or annual time scales. ● Hydrological drought is related to the effects of precipitation shortfalls on stream flows and reservoir, lake, and groundwater levels. ● Agricultural drought is defined principally in terms of soil moisture deficiencies relative to water demands of plant life, usually crops. ● Socioeconomic drought associates the supply and demand of economic goods or services with elements of meteorological, hydrological, and agricultural drought. Socioeconomic drought occurs when the demand for water exceeds the supply as a result of weather- related supply shortfall. It may also be referred to as a water management drought.
A drought’s severity depends on numerous factors, including duration, intensity, and geographic extent as well as regional water supply demands by humans and vegetation. Due to its multidimensional nature, drought is difficult to define in exact terms and also poses difficulties in terms of comprehensive risk assessments.
Drought differs from other natural hazards in three ways. First, the onset and end of a drought are difficult to determine due to the slow accumulation and lingering of effects of an event after its apparent end. Second, the lack of an exact and universally accepted definition adds to the confusion of its existence and severity. Third, in contrast with other natural hazards, the impact of drought is less obvious and may be spread over a larger geographic area. These characteristics have hindered the preparation of drought contingency or mitigation plans by many organizations.
The effects of drought increase with duration as more moisture-related activities are impacted. Non-irrigated croplands are most susceptible to precipitation shortages. Rangeland and irrigated
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Literature Review Summary SWCC agricultural crops may not respond to moisture shortage as rapidly, but yields during periods of drought can be substantially affected. During periods of severe drought, lower moisture in plant and forest fuels create an increased potential for devastating wildfires. In addition, lakes, reservoirs, and rivers can be subject to water shortages that impact recreational opportunities, irrigated crops, availability of water supplies for activities such as fire suppression and human consumption, and natural habitats of animals. Insect infestation can also be a particularly damaging impact from severe drought conditions.
Nine notable droughts occurred in the United States during the 20th century. Although damage estimates are not available for many of these events, estimates suggest that direct losses exceed $49-54 billion in damages. The 1930s “Dust Bowl” drought was the United States’ most severe, sustained, and widespread event in the past 300 years.
Based on the Palmer Drought Severity Index (PDSI) and Palmer Hydrological Drought Index (PHDI) (see http://drought.unl.edu/Planning/Monitoring/ComparisonofIndicesIntro/PDSI.aspx) sustained periods of moderate drought conditions have occurred regularly, at least 8 times, in Southwestern Virginia since 1896 and severe drought has occurred twice since 1896.
Credit: National Oceanic and Atmospheric Administration
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Credit: National Oceanic and Atmospheric Administration
The most recent severe drought occurred in 2007 and 2008 affecting agriculture and resulting in the implementation of some water restrictions in Southwest Virginia. A search of media reports concerning the drought provided links to many articles describing the effects of the drought in Southwest Virginia. Some examples of those articles can be found at the following web links:
● http://www2.swvatoday.com/news/2007/jul/29/farmers_frying_in_heat_drought-ar- 1487480/ ● http://www2.swvatoday.com/news/2008/feb/02/drought_persists_into_08-ar-1486353/ ● http://www2.swvatoday.com/news/2008/may/13/drought_aid_for_farmers-ar-1485598/ ● http://www2.swvatoday.com/news/2007/aug/14/farmers_eligible_for_aid-ar-1487371/ ● http://www2.swvatoday.com/news/2007/dec/20/farmers_hurting_for_hay-ar-1486608/ ● http://www2.swvatoday.com/news/2008/jan/02/looking_back_at_2007_july_to_decembe r-ar-1486570/
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Earthquake
An earthquake is a sudden slip or movement of a portion of the earth’s crust accompanied and followed by a series of vibrations. This movement releases energy (so-called seismic energy) is capable of sending seismic waves hundreds of miles through the Earth’s crust and causing massive destruction. The magnitude of an earthquake is defined by the amount of released seismic energy. Measurement scales for earthquake magnitude/size are the Richter scale and the Moment-Magnitude scale. Earthquake intensity – meaning the level of shaking - is measured by the Mercalli intensity scale.
It is important to understand that the amount of shaking is not solely a function of an earthquake’s magnitude and the amount of energy released. The closer a locality to the epicenter, the more likely it is for this location to experience stronger shaking. Also, the deeper the focus, the less shaking tends to occur on the surface since seismic waves lose energy the longer they travel through the crust before reaching the surface. However, not all places equidistant from the epicenter or focus will experience the same amount of shaking. In some areas, shaking might be stronger due to ground conditions that either amplify or dampen shaking. Seismic waves can occur prior to an earthquake (so-called foreshocks) as well as after the event (so-called aftershocks) causing ongoing potential for destruction. Not all earthquakes have foreshocks and aftershocks but significant earthquakes are associated with aftershocks.
Aftershocks can be extremely devastating and deadly because they occur when infrastructure is weakened and compromised by the initial earthquake. The SWCC is at risk from earthquakes. SWCC has about a 6-8% chance of an earthquake greater than magnitude 5 within 100 years and a 50 kilometer radius. Although the faults in Virginia exhibit low seismicity it cannot be assumed that these faults are incapable of producing significant earthquakes with damaging ground motion. Historic evidence indicates that these fault lines have not generated significant earthquakes in the past but this does not mean that it is impossible. Hazards often associated with earthquakes that could be a threat to the SWCC campus are fires due to broken gas pipes and structural failures as well as liquefaction.
The maps displayed below show how earthquake hazards vary across the United States. Hazards are measured as the likelihood of experiencing earthquake shaking of various intensities. The colors in the maps denote “seismic design categories” (SDCs), which reflect the likelihood of experiencing earthquake shaking of various intensities. Building design and construction professionals use SDCs specified in building codes to determine the level of seismic resistance required for new buildings.
The following table describes the hazard level associated with each SDC, and the associated levels of shaking. Although stronger shaking is possible in each SDC, it is less probable than the shaking described.
SDC Map Color Earthquake Hazard Potential Effects of Shaking*
A White Very small probability of experiencing damaging earth-quake effects.
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B Gray Could experience shaking of Moderate shaking—Felt by all, moderate intensity. many frightened. Some heavy furniture moved; a few instances of fallen plaster. Damage slight. C Yellow Could experience strong Strong shaking—Damage shaking. negligible in buildings of good design and construction; slight to moderate in well-built ordinary structures; considerable damage in poorly built structures. D0 Light brown Could experience very strong Very strong shaking—Damage shaking (the darker the color, slight in specially designed the stronger the shaking). structures; considerable damage in ordinary substantial buildings with partial collapse. Damage great in poorly built structures. D1 Darker brown
D2 Darkest brown
E Red Near major active faults Strongest shaking—Damage capable of producing the most considerable in specially intense shaking. designed structures; frame structures thrown out of plumb. Damage great in substantial buildings, with partial collapse. Buildings shifted off foundations. Shaking intense enough to completely destroy buildings. * Abbreviated descriptions from The Modified Mercalli Intensity Scale.
SDCs take into account the type of soil at the site, as poor soils can significantly increase earthquake shaking. These maps have simplified this by assuming normal Site Class “D” soils, which are the most commonly found.
When viewing the maps, it is important to remember that areas with high earthquake hazards do not necessarily face high seismic risks. Defined as the losses that are likely to result from exposure to earthquake hazards, seismic risks are determined not only by hazard levels but also by the amount of people and property that are exposed to the hazards, and by how vulnerable people and property are to the hazards. This is explained in more detail in Your Earthquake Risk.
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Credit: Federal Emergency Management Agency
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Credit: U.S. Geological Survey
Credit: U.S. Geological Survey
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On December 3, 2011 at 6:12 a.m. a 3.1 magnitude earthquake centered in Claypool Hill, Virginia caused weak shaking on the SWCC campus.
Credit: U.S. Geological Survey
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More recently, on November 10, 2012 at 12:08 p.m. a 4.3 magnitude earthquake occurred outside Whitesburg, Kentucky that was felt in Eastern and Central Kentucky and seven other states in the region. The SWCC campus felt light shaking causing heavy objects such as computer monitors to move on shelves.
Credit: U.S. Geological Survey
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A search of news articles related to the Whitesburg, Kentucky earthquake revealed many articles describing the widespread shaking felt in the region. Links to some of the articles are below: http://www.timesnews.net/article/9053925/43-magnitude-earthquake-reported-in-eastern-kentucky http://www.timesnews.net/article.php?id=9054397 http://bdtonline.com/local/x1501154828/Quake-rattles-region http://www.kentucky.com/2012/11/10/2402918/updated-earthquake-centered-near.html http://www.wbir.com/rss/article/241460/2/Expert-KY-earthquake-isolated-but-more-common-than- you-think
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Flood and Flash Flood
Floods occur when excess water from snowmelt, rainfall, or storm surges accumulates and overflows onto adjacent floodplains. Floodplains are lowlands adjacent to rivers, lakes, and oceans that are subject to recurring floods. As a natural event, floods are considered hazards only when people or property is affected. Nationwide, hundreds of floods occur each year, making it one of the most common hazards across the nation (FEMA, 1997). The Cumberland Plateau Regional Planning District identified common flood types occurring in Virginia. These categories are described as follows:
● Channel flooding is characterized by lateral river and stream channel migration during major flows, which results in abrupt changes in the horizontal alignment or location of the channel. Other characteristics include localized channel bed and bank-scour in addition to the potential for over-bank flow inundation.
● Sheet flooding is characterized by a channel having minimal capacity, water flowing across broad areas at relatively shallow depths, and gently sloping terrain. Damage from these events includes localized scour and deposition of extensive amounts of sediments and debris typically associated with sheet flow. If the depth of the water is high enough, water may encroach into low-lying structures within the floodplain.
● Alluvial fan flooding refers to flooding occurring on the surface of an alluvial fan or similar landform characterized by high-velocity flows, active erosion processes, sediment transportation and deposition, and unpredictable flow paths. Flow depths with alluvial fan flooding are generally shallow with damage resulting from inundation, variable flow paths, localized scour and the deposition of debris. Alluvial flooding is potentially more dangerous than riverine flooding due to its unpredictable nature resulting in difficulties associated with threat identification.
● Another type of flooding is caused by heavy rainfall in the mountain areas resulting in the massive melting of the snowpack leading to heavy runoff, widespread damage to roads and other transportation facilities, and bank erosion.
Factors determining the severity of floods include rainfall intensity and duration. Excessive rainfall within the Commonwealth is often associated with frontal systems out of the northeast and the remnants of tropical storms from the south.
Most residents and visitors are unaware of the flood potential or never see flooding occur until it is too late. In addition to the tremendous property damage and deaths related to flooding, SWCC students and staff can experience inconvenience when roads become difficult to navigate, or are completely impassable. Support services such as police, fire, and ambulance are sometimes delayed in responding to victims of life-threatening incidents. Flood and flash flood events can
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Literature Review Summary SWCC also adversely impact the local economy through loss of business at commercial establishments due to decreased access.
While SWCC is not situated in a floodplain, flooding and flash flooding in the surrounding areas could affect access to the campus and campus operations. From 10/1/06-10/1/12 flash flooding occurred 19 times in Tazewell County and 3 times in Russell County. From 10/1/06-10/1/12 flooding occurred 3 times in Tazewell County due to heavy rain runoff and the Clinch River rose to just below minor flood stage. During the same period, Russell County experienced flooding 3 times due to heavy rain runoff.
Flood Map of Tazewell County in the Vicinity of SWCC
Credit: Federal Emergency Management Agency
Flood Map of Russell County in the Vicinity of SWCC
Credit: Federal Emergency Management Agency
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Hazardous Materials
A hazardous material is a substance in a quantity or form posing an unreasonable risk to health, safety or property when manufactured, stored, or transported in commerce. These are substances which by their nature, containment, and reactivity have the capability for inflicting harm during an accidental occurrence, characterized as being toxic, corrosive, flammable, reactive, an irritant, or a strong sensitizer and thereby posing a threat to health and the environment when improperly managed. This category includes Hazardous Chemicals (HC), Hazardous Substances (HS), Extremely Hazardous Substances (EHS), toxic substances, certain infectious agents, radiological materials, and other related materials such as oil, used oil, petroleum products, and industrial solid waste substances.
Hazardous chemicals (HC) are those chemicals, chemical mixtures, and other chemical products determined by US Occupational Health and Safety Administration (OSHA) regulations to pose a physical or health hazard. No specific list of chemicals exists, but the existence of a Material Safety Data Sheet (MSDS) for a product indicates it is a hazardous chemical. Facilities that maintain more than 10,000 pounds of a HC at any time are required to report inventories of such chemicals annually to the State Emergency Response Commission (SERC).
Hazardous substances (HS) are designated as such by the United States Environmental Protection Agency (USEPA) pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Facilities which have more than 10,000 pounds of any HS at any time are required to report inventories of such substances annually to the SERC. HS releases above certain levels must be reported to the National Response Center, the SERC, and local agencies pursuant to the CERCLA, Section 304 of EPCRA, and state regulations. The roughly 720 HS and pertinent reporting quantities are listed in 40 CFR 302.4. In November of 1986, Congress passed the Emergency Planning and Community Right-to-Know Act (EPCRA), a law designed to help America's communities deal safely and effectively with the many hazardous substances that society uses.
Extremely hazardous substances (EHS) are designated as such by the USEPA pursuant to the EPCRA. EHS inventories above certain threshold quantities must be reported annually to the SERC, local emergency planning committees (LEPCs), and local fire departments pursuant to Section 312 of EPCRA. EHS releases which exceed certain quantities must be reported to the National Response Center, the SERC, and local agencies pursuant to Section 304 of EPCRA and state regulations. The roughly 360 EHSs, and pertinent reporting quantities, are listed in 40 CFR 355.
Toxic substances (TS) produce long-term adverse health effects. Facilities which manufacture or process more than 25,000 pounds of any designated toxic substance or use more than 10,000
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Acutely Toxic Chemicals (ATC) can cause both severe short term and long term health effects after a single, brief exposure of short duration. These chemicals can cause damage to living tissue, impairment of the central nervous system and severe illness. In extreme cases, death can occur when ingested, inhaled, or absorbed through the skin.
The most frequent mode for transportation of hazardous materials is on major highway systems. All shipments of radioactive materials, whether from industry or government, must be packaged and transported according to strict federal regulations. These regulations protect the public, transportation workers, and the environment from potential exposure. The types of packaging used are determined by the activity, type, and form of the materials to be shipped.
Facilities that manufacture, store, use, or dispose of hazardous materials have the requirement to establish emergency response procedures, including evacuation plans, for dealing with accidental chemical releases. The facility plan sets up the notification procedures for those facility personnel who will respond to an emergency. The plan establishes the methods for determining the occurrence and severity of a release and the areas and populations likely to be affected at the facility. The facility plan identifies the emergency response equipment, if any, available at the facility. The facility conducts training and exercise programs with a general training schedule for the facility responders. The facility identifies coordinators to carry out the facility plan. Finally, the facility plan provides the method for contacting or notifying the local first response agency that is, in most cases, the local fire department.
A major concern for water wells and water purveyors is the potential for spills of hazardous materials on top of the ground, and what those incidents might create in terms of hazards for water users.
The US EPA lists no Superfund sites in Russell and Tazewell counties. For 2011, the US EPA lists no Toxic Release Inventory (TRI) incidents for the SWCC zip code 24609. There are 5 distinct TRI sites in Russell and Tazewell counties, but none are in proximity to SWCC. From 10/06 through 10/12, there were no recorded highway transit incidents involving hazardous materials for zip code 24609.
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Karst Terrain
In regions of carbonate bedrock such as limestone or dolomite, rainwater percolating through organic soil becomes slightly acidic and as it comes into contact with the bedrock, it slowly dissolves the carbonate minerals. Over time, this persistent process can create extensive systems of underground fissures and caves. The surface of such a region is often dotted with sinkholes and closed depressions. This type of topography is called karst terrain. In well-developed karst terrain, chains of sinkholes form what are known as solution valleys and streams frequently disappear underground.
Sinkholes are bowl-shaped, funnel-shaped, or vertical-sided depressions in the land surface that form over underground voids. These depressions, which can range in size from a few feet to several hundred feet in diameter and depth, usually result from the natural collapse of the roofs of caves eroded in soluble bedrock, but they can also result from man-made activity such as mining, groundwater pumping, or the failure of sewer and storm water drains. Subsidence of the ground is usually gradual, but on occasions it can be sudden and dramatic.
A sinkhole that formed in Russell County, Virginia. Credit: Virginia Department of Mines, Minerals, and Energy:
Sinkholes provide a pathway for surface water to directly enter groundwater aquifers, so the potential for pollution is high because of the minimal filtering of surface water. A May 2011 evaluation of water quality in Russell and Tazewell counties found the presence of coli form bacteria that entered the water table through sinkholes. Although harmless in itself, it is an indicator organism that could indicate the presence of more dangerous bacteria and microorganisms.
Karst terrain is present in both Russell and Tazewell counties. Most karst terrain hazards are identified and codes limit building on hazard areas. Historic damages and losses are negligible. SWCC is susceptible to Karst terrain as caves are present on campus property and impacted the construction of the Community Center.
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Landslides and Debris Flow
A landslide is a movement of surface material down a slope. The term landslide includes a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris flows. Although gravity acting on an over-steepened slope is the primary reason for a landslide, there are other contributing factors:
● erosion by rivers creates over steepened slopes ● rock and soil slopes are weakened through saturation by snowmelt or heavy rains ● earthquakes create stresses that make weak slopes fail ● earthquakes of magnitude 4.0 and greater have been known to trigger landslides ● excess weight from accumulation of rain or snow, stockpiling of rock or ore, from waste piles, or from man-made structures may stress weak slopes to failure and other structures
Slope materials that become saturated with water may develop a debris flow or mudflow. The resulting slurry of rock and mud may pick up trees, houses, and cars, thus blocking bridges and tributaries causing flooding along its path.
Post-wildfire landslide hazards include fast-moving, highly destructive debris flows that can occur in the years immediately after wildfires in response to high intensity rainfall events, and those flows that are generated over longer time periods accompanied by root decay and loss of soil strength. Post-fire debris flows are particularly hazardous because they can occur with little warning, can exert great impulsive loads on objects in their paths, can strip vegetation, block drainage ways, damage structures, and endanger human life. Wildfires could potentially result in the destabilization of pre-existing deep-seated landslides over long time periods.
Landslides occur in every state and U.S. territory. The Appalachian Mountains have severe landslide problems. Any area composed of very weak or fractured materials resting on a steep slope can and will likely experience landslides.
Areas prone to landslides exist:
● On existing old landslides. ● On or at the base of slopes. ● In or at the base of minor drainage hollows. ● At the base or top of an old fill slope. ● At the base or top of a steep cut slope. ● Developed hillsides where leach field septic systems are used.
There have been no reportable landslides resulting from storm related events in Russell and Tazewell Counties from 10/1/06 to 11/29/12. VDOT has identified eight landslide locations in Russell County and fourteen locations in Tazewell County, primarily along major roadways.
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Credit: Cumberland Plateau Regional Planning District
These do not represent all landslide occurrences. Others occurring with no public impact generally are not recorded.
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Space Weather
Space weather describes the conditions in space that affect Earth and its technological systems. Space weather is a consequence of the behavior of the Sun, the nature of Earth’s magnetic field and atmosphere, and our location in the solar system. The active elements of space weather are particles, electromagnetic energy, and magnetic field, rather than the more commonly known weather contributors of water, temperature, and air.
There are three main types of space weather: solar flares, solar radiation storms, and geomagnetic storms.
Solar flares occur when magnetic energy builds up and erupts in the Sun’s atmosphere, ejecting radiation and superheated particles. These violent, short-lived eruptions are the most energetic explosions in the entire solar system and their frequency is dictated by the Sun’s eleven-year cycle. They are seen as bright areas on the Sun in optical wavelengths and as bursts of noise in radio wavelengths; they can last from minutes to hours. The primary energy source for flares appears to be the tearing and reconnection of strong magnetic fields. They radiate powerful bursts of energy throughout the electromagnetic spectrum, from gamma rays to x-rays, through visible light out to kilometer-long radio waves. Solar flare radio blackouts often serve as a precursor to geomagnetic and solar radiation storms.
Credit: National Park Service
During periods of high solar activity, several radio blackouts can occur in a 24-hour period. Solar flare radio blackouts have potential to interfere with or seriously degrade response and recovery capabilities by impacting HF radio communications, GPS applications, satellite communications, and search and rescue satellite-aided tracking. They can also create political, public, or media pressure as well as the expectation for emergency management actions.
Solar radiation storms occur when explosions on the sun accelerate solar protons toward Earth. These protons stream past Earth, where they are usually deflected by earth’s protective magnetic field. High-energy particles, mostly protons, can render satellites useless either for a short time
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Literature Review Summary SWCC or permanently because of the impact on sensitive electronics. Capability can be degraded or lost for minutes up to an hour.
Geomagnetic storms can affect satellites, power grids and communication lines by interrupting their normal electronic and magnetic components. The word geomagnetic refers to the magnetic principles of the Earth, which are controlled by the rotation of the planet and the physical characteristics of the Earth’s metal core. The Earth’s magnetic field experiences normal fluctuations but during a geomagnetic storm, the disturbances caused by solar weather are so great that they generate electrical currents known as geomagnetically induced currents, GICs. These currents can disrupt or damage electronic equipment.
The effects of space weather are best classified in the categories of “primary” and “cascading”, or secondary, effects. Primary effects are those that are a direct result of space weather (e.g. radio blackouts, electric power grid disruptions, GIS disruptions etc). Cascading effects are those effects that result from the primary effects (e.g. business, government, universities, colleges, and hospitals not being able to function properly, transportation disruptions etc.) Much of the space weather information is taken from a National Academy of Sciences workshop report titled “Severe Space Weather Events—Understanding Societal and Economic Impacts.” For a PDF of this report go to http://www.nap.edu/catalog/12507.html
A literature review did not find any recorded events of space weather affecting SWCC.
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Literature Review Summary SWCC
Tornadoes
A tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground. Because wind is invisible, it is hard to see a tornado unless it forms a condensation funnel made up of water droplets, dust and debris. Tornadoes are the most violent of all atmospheric storms.
Tornadoes come from mainly two types of thunderstorms: supercell and non-supercell. Tornadoes that come from a supercell thunderstorm are the most common, and often the most dangerous. A rotating updraft is a key to the development of a supercell, and eventually a tornado. Non-supercell tornadoes are circulations that do not form from organized storm-scale rotation. These tornadoes form from a vertically spinning parcel of air already occurring near the ground caused by wind shear from a warm, cold, or sea breeze front, or a dryline. When an updraft moves over the spinning, and stretches it, a tornado can form.
The most destructive and deadly tornadoes occur from supercells, which are rotating thunderstorms with a well-defined radar circulation called a mesocyclone. Supercells can also produce damaging hail, severe non-tornadic winds, unusually frequent lightning, and flash floods. Tornado formation is believed to be dictated mainly by things which happen on the storm scale, in and around the mesocyclone. Recent theories suggest that once a mesocyclone is underway, tornado development is related to the temperature differences across the edge of downdraft air wrapping around the mesocyclone. Mathematical modeling studies of tornado formation also indicate that it can happen without such temperature patterns; and in fact, very little temperature variation was observed near some of the most destructive tornadoes in history.
Tornado season usually refers to the time of year the U.S. sees the most tornadoes. In the northern plains and upper Midwest, tornado season is in June or July. But, tornadoes can happen at any time of year. Tornadoes can also happen at any time of day or night, but most tornadoes occur between 4–9 pm.
The Enhanced Fujita (EF) scale is an update to the original Fujita Scale (F-Scale) developed by a team of meteorologists and wind engineers and implemented in the U.S. on 1 February 2007. The EF-Scale takes into account more variables than the original when assigning a wind speed rating to a tornado, incorporating 28 damage indicators such as building type, structures and trees.
Wind incidents producing between EF-0 and EF-2 occurred in Russell County five times, producing $65,000 damage between October 2006 and November 2012. There were no deaths or injuries during this timeframe. Zero incidents occurred in Tazewell County during the same period.
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Wildfire
A wildfire is an uncontrolled fire spreading through vegetative fuels, exposing and possibly consuming structures. They often begin unnoticed and spread quickly. Wildfires can be human- caused through acts such as arson, campfires, or the improper burning of debris, or can be caused by natural events such as lightning. Wildfires can be categorized into four types:
● Wildland fires occur mainly in areas under federal control, such as national forests and parks, and are fueled primarily by natural vegetation. Generally, development in these areas is nonexistent, except for roads, railroads, power lines, and similar features. ● Interface or intermix fires occur in areas where both vegetation and structures provide fuel. These are also referred to as Wildland/Urban Interface (WUI) fires. ● Firestorms occur during extreme weather (e.g., high temperatures, low humidity, and high winds) with such intensity that fire suppression is virtually impossible. These events typically burn until the conditions change or the fuel is exhausted. ● Prescribed fires and prescribed natural fires are intentionally set or natural fires that are allowed to burn for beneficial purposes.
The following three factors contribute significantly to wildfire behavior and, as detailed more fully later, they can be used to identify wildfire hazard areas:
● Topography: Although it generally remains unchanged, unlike fuel or weather, topography can either aid or hinder wildfire progression. The most important topographical factor is slope. ● Fuel: Wildfires spread based on the type and quantity of available flammable material, referred to as the fuel load. The basic characteristics of fuel include size and shape, arrangement and moisture content. ● Weather: The most variable factor affecting wildfire behavior is weather. Important weather variables are temperature, humidity, wind, and lightning. Weather events ranging in scale from localized thunderstorms to large fronts can have major effects on wildfire occurrence and behavior. Extreme weather, such as high temperatures and low humidity, can lead to extreme wildfire activity. By contrast, cooling and higher humidity often signals reduced wildfire occurrence and easier containment. Wind has probably the largest impact on a wildfire’s behavior, and is also the most unpredictable. Winds supply the fire with additional oxygen, further dry potential fuel, and push fire across the land at a quicker pace.
The frequency and severity of wildfires is also dependent upon other hazards, such as lightning, drought, and infestations (e.g., Pine Bark Beetle). In Virginia, these hazards combine with the three other wildfire contributors noted above (topography, fuel, weather) to present an on-going and significant hazard across much of Virginia.
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Literature Review Summary SWCC
If not promptly controlled, wildfires may grow into an emergency or disaster. Even small fires can threaten lives, resources, and destroy improved properties. It is also important to note that in addition to affecting people, wildfires may severely affect livestock and pets. Such events may require the emergency watering/feeding, shelter, evacuation, and even burying of animals.
The indirect effects of wildfires can also be catastrophic. In addition to stripping the land of vegetation and destroying forest resources, large, intense fires can harm the soil, waterways and the land itself. Soil exposed to intense heat may lose its capability to absorb moisture and support life. Exposed soils erode quickly and enhance siltation of rivers and streams thereby enhancing flood potential, harming aquatic life and degrading water quality. Lands stripped of vegetation are also subject to increased landslide hazards.
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Literature Review Summary SWCC
Wind and Severe Thunderstorms (Adapted from the CPPDC plan)
Wind can be one of the most destructive forces of nature. Strong winds can erode mountains and shorelines, topple trees and buildings, and destroy a community's critical utilities and infrastructure. Primarily, damaging winds that affect the region are associated with severe thunderstorms, or the remnants of a tropical storm or hurricane. Winds from a severe thunderstorm can reach over 60 mph in the southwest Virginia region. These storms generally develop along a cold front and can extend for hundreds of miles.
Records of the impacts of high wind events in the region are limited. The relatively large distance between the SWCC location and the Atlantic Coast limit the impacts of the winds associated with hurricanes and tropical storms. Because the highest winds speeds associated with a hurricane or tropical storm are typically located to the east of the storm's eye, and the path of most of these storms are to the east of SWCC, extremely high winds from these events are rare. Damaging winds from severe thunderstorms have occurred throughout Southwest Virginia on a regular basis. Wind damages have typically been localized throughout the region and have included broken tree limbs, blown down trees, damage to power lines, and moderate building damage.
Incidents generally occur between October 1 and May 31 annually. From 10/1/06-11/30/12 Tazewell has experienced storms with winds 50+ on 41 occasions resulting in no injuries or crop damage, but $472.95K property damage. During the same period, Russell County experienced storms with winds 50+ on 35 occasions resulting in no injuries or crop damage, but $214K property damage. During the same time period, Tazewell County experienced hail storms 45 times (.75 to 2.0 inch) resulting in 57K property damage but no injuries or crop damage. Again, during the same time period Russell County experienced hail storms 10 times (.75 to 1.75 inch) resulting in no injuries, property damage, or crop damage.
On March 11, 2011, the SWCC campus experienced a severe thunderstorm accompanied by excessive rain that caused approximately $78,000 of damage. The thunderstorm/rain event caused major leaks to the Learning Resources Center where the water ended up traveling downstairs into the Distance Education equipment room where several servers became very wet. The online class delivery system was knocked out.
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Winter Storm (Adapted from the CPPDC Plan)
Although the Commonwealth of Virginia is not generally associated with severe winter storms, the mountainous area in the southwestern portion of the state regularly experiences several snow storms each year. These storms can produce between 4 and 12 inches of snow from each event. However, storms producing higher snowfall amounts are possible. Russell County can experience up to 21" per year, and Tazewell County up to 40" per year.
In addition to snow, winter storms can also bring sleet and freezing rain to the area. Sleet is generally described as frozen water particles that fall in the form of ice, while freezing rain falls as super cooled water which can freeze on impact with the ground, trees, or roadways. In its most severe form, freezing rain can fall as part of an ice storm that can coat the area with a layer of ice up to 3" thick. Ice storms can cause significant damage by snapping tree limbs and bending trees to the ground. These fallen limbs and trees can completely block roadways, cut access to certain areas in the vicinity of SWCC for days, and interfere with and destroy overhead utility lines.
Winter storms can disrupt lives for periods of a few hours or up to several days, depending upon the severity of the storm. Transportation systems are usually among the first and hardest hit sectors of a community. Snow and ice can block primary and secondary roads, and treacherous conditions make driving difficult; some motorists may be stranded during a storm, and emergency vehicles may not be able to access all areas. The steep slopes found throughout the region exacerbate the situation, making some of the secondary roads impassable during even a minor winter weather event.
Utility infrastructure also can be adversely affected by winter storms. Heavy snow and ice can cause power lines to snap, leaving the college without power and, in some cases, heat for hours or even days. Likewise, telephone lines can also snap, disabling communications. Frozen water pipes can rupture, and water and sewer mains can also freeze and leak or rupture if not properly maintained. These ruptures can lead to flooding and property damage.
People's health can also be adversely affected by severe winter weather. People who lose heat and do not seek alternate shelter, people who get stuck in snow drifts while driving, or people working and playing outdoors can suffer from hypothermia and frostbite. Because winter weather hazards generally affect the entire region and vary in intensity and form, it is not possible to quantify primary effects or specific damages.
The NOAA Storm Events database listed no events in Russell County from 10/01/2006- 10/31/2012. The database listed 5 events in Tazewell County that resulted in no deaths, injuries, property damage, or crop damage.
A winter storm accompanied by high winds in February 2010 caused approximately $35,000 damage to the SWCC campus. Numerous large trees on campus were damaged or lost and there was some roof and window damage; some windows were actually blown out by the wind.
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Recommended Approach and Methods for Vulnerability Assessment
We propose to employ the vulnerability assessment criteria described by the National Oceanic and Atmospheric Administration (NOAA). Table A, Hazard Ranking Criteria, depicts the criteria to apply, that will result in a ranked list of hazards that SWCC could consider in its planning activities. Each criterion contributes to a relative vulnerability figure that is useful in comparing hazards among each other.
Table A. Hazard Ranking Criteria
Hazard Points Frequency Area Impact Magnitude Assigned
1 10+ years Site (x,y) Insured Loss
2 6-9 years Block Group Local Funds
3 1-5 years Census Tract State Assistance
4 2-12 Township, Range Federal Emergency months
5 0-30 days County Federal Disaster
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