Wellhart Glossary of Terms

Words, Phrases, Abbreviations, and Acronyms Relevant to Emergency Management Defined

American Red Cross: The American Red Cross is a humanitarian organization, led by volunteers, that provides relief to victims of disasters and helps people prevent, prepare for, and respond to emergencies. It does this through services that are consistent with its Congressional Charter and the Principles of the International Red Cross Movement.

Attack: A hostile action taken against the United States by foreign forces or terrorists, resulting in the destruction of or damage to military targets, injury or death to the civilian population, or damage or destruction to public and private property.

Checklist: Written (or computerized) enumeration of actions to be taken by an individual or organization, meant to aid memory rather than provide detailed instruction.

Chief Executive Official: The official of the community who is charged with authority to implement and administer laws, ordinances, and regulations for the community. He or she may be a mayor, city manager, etc.

Community: A political entity which has the authority to adopt and enforce laws and ordinances for the area under its jurisdiction. In most cases, the community is an incorporated town, city, township, village, or unincorporated area of a county. However, each State defines its own political subdivisions and forms of government.

Contamination: The undesirable deposition of a chemical, biological, or radiological material on the surface of structures, areas, objects, or people.

Dam: A barrier built across a watercourse for the purpose of impounding, controlling, or diverting the flow of water.

Damage Assessment: The process used to appraise or determine the number of injuries and deaths, damage to public and private property, and the status of key facilities and services such as hospitals and other health care facilities, fire and police stations, communications networks, water and sanitation systems, utilities, and transportation networks resulting from a man-made or natural disaster.

Decontamination: The reduction or removal of a chemical, biological, or radiological material from the surface of a structure, area, object, or person.

Disaster: An occurrence of a natural catastrophe, technological accident, or human caused event that has resulted in severe property damage, deaths, and/or multiple injuries. As used in this Guide, a “large-scale disaster” is one that exceeds the response capability of the local jurisdiction and requires State, and potentially Federal, involvement. As used in the Stafford Act, a “major disaster” is “any natural catastrophe […] or, regardless of cause, any fire, flood, or explosion, in any part of the United States, which in the determination of the President causes damage of sufficient severity and magnitude to warrant major disaster assistance under [the] Act to supplement the efforts and available resources or States, local governments, and disaster relief organizations in alleviating the damage, loss, hardship, or suffering caused thereby.”

Disaster Field Office: The office established in or near the designated area of a Presidentially declared major disaster to support Federal and State response and recovery operations. The DFO houses the FCO and ERT, and where possible, the SCO and support staff.

Disaster Recovery Center: Places established in the area of a Presidentially declared major disaster, as soon as practicable, to provide victims the opportunity to apply in person for assistance and/or obtain information relating to that assistance. DRCs are staffed by local, State, and Federal agency representatives, as well as staff from volunteer organizations (e.g., the ARC).

Dose (Radiation): A general term indicating the quantity (total or accumulated) of ionizing radiation or energy absorbed by a person or animal.

Dose Rate: The amount of ionizing radiation which an individual would absorb per unit of time. Dosimeter An instrument for measuring and registering total accumulated exposure to ionizing radiation. Earthquake The sudden motion or trembling of the ground produced by abrupt displacement of rock masses, usually within the upper 10 to 20 miles of the earth’s surface.

Electromagnetic Pulse: A sharp pulse of energy radiated instantaneously by a nuclear detonation which may affect or damage electronic components and equipment.

Emergency: Any occasion or instance–such as a hurricane, tornado, storm, flood, tidal wave, tsunami, earthquake, volcanic eruption, landslide, mudslide, snowstorm, fire, explosion, nuclear accident, or any other natural or man-made catastrophe–that warrants action to save lives and to protect property, public health, and safety.

Emergency Alert System: A digital technology (voice/text) communications system consisting of broadcast stations and interconnecting facilities authorized by the Federal Communication Commission. The system provides the President and other national, State, and local officials the means to broadcast emergency information to the public before, during, and after disasters.

Emergency Environmental Health Services: Services required to correct or improve damaging environmental health effects on humans, including inspection for food contamination, inspection for water contamination, and vector control; providing for sewage and solid waste inspection and disposal; clean-up and disposal of hazardous materials; and sanitation inspection for emergency shelter facilities.

Emergency Health Services: Services required to prevent and treat the damaging health effects of an emergency, including communicable disease control, immunization, laboratory services, dental and nutritional services; providing first aid for treatment of ambulatory patients and those with minor injuries; providing public health information on emergency treatment, prevention, and control; and providing administrative support including maintenance of vital records and providing for a conduit of emergency health funds from State and Federal governments.

Emergency Medical Services: Services, including personnel, facilities, and equipment required to ensure proper medical care for the sick and injured from the time of injury to the time of final disposition, including medical disposition within a hospital, temporary medical facility, or special care facility, release from site, or declared dead. Further, emergency medical services specifically include those services immediately required to ensure proper medical care and specialized treatment for patients in a hospital and coordination of related hospital services.

Emergency Mortuary Services: Services required to assure adequate death investigation, identification, and disposition of bodies; removal, temporary storage, and transportation of bodies to temporary morgue facilities; notification of next of kin; and coordination of mortuary services and burial of unclaimed bodies.

Emergency Operating Center: The protected site from which State and local civil government officials coordinate, monitor, and direct emergency response activities during an emergency.

Emergency Operations Plan: A document that: describes how people and property will be protected in disaster and disaster threat situations; details who is responsible for carrying out specific actions; identifies the personnel, equipment, facilities, supplies, and other resources available for use in the disaster; and outlines how all actions will be coordinated.

Emergency Planning Zones: Areas around a facility for which planning is needed to ensure prompt and effective actions are taken to protect the health and safety of the public if an accident occurs. The REP Program and CSEPP use the EPZ concept.

In the REP Program, the two EPZs are:

  • Plume Exposure Pathway (10-mile EPZ). A circular geographic zone (with a 10-mile radius centered at the nuclear power plant) for which plans are developed to protect the public against exposure to radiation emanating from a radioactive plume caused as a result of an accident at the nuclear power plant.
  • Ingestion Pathway (50-mile EPZ). A circular geographic zone (with a 50-mile radius centered at the nuclear power plant) for which plans are developed to protect the public from the ingestion of water or foods contaminated as the result of a nuclear power plant accident.

In CSEPP, the EPZ is divided into three concentric circular zones:

  • Immediate Response Zone (IRZ). A circular zone ranging from 10 to 15 km (6 to 9 miles) from the potential chemical event source, depending on the stockpile location on-post. Emergency response plans developed for the IRZ must provide for the most rapid and effective protective actions possible, since the IRZ will have the highest concentration of agent and the least amount of warning time.
  • Protective Action Zone (PAZ). An area that extends beyond the IRZ to approximately 16 to 50 km (10 to 30 miles) from the stockpile location. The PAZ is that area where public protective actions may still be necessary in case of an accidental release of chemical agent, but where the available warning and response time is such that most people could evacuate. However, other responses (e.g., sheltering) may be appropriate for institutions and special populations that could not evacuate within the available time.
  • Precautionary Zone (PZ). The outermost portion of the EPZ for CSEPP, extending from the PAZ outer boundary to a distance where the risk of adverse impacts to humans is negligible. Because of the increased warning and response time available for implementation of response actions in the PZ, detailed local emergency planning is not required, although consequence management planning may be appropriate.

Emergency Response Team: An interagency team, consisting of the lead representative from each Federal department or agency assigned primary responsibility for an ESF and key members of the FCO’s staff, formed to assist the FCO in carrying out his/her coordination responsibilities. The ERT may be expanded by the FCO to include designated representatives of other Federal departments and agencies as needed. The ERT usually consists of regional-level staff.

Emergency Response Team Advance Element: For Federal disaster response and recovery activities under the Stafford Act, the portion of the ERT that is first deployed to the field to respond to a disaster incident. The ERT-A is the nucleus of the full ERT.

Emergency Response Team National: An ERT that has been established and rostered for deployment to catastrophic disasters where the resources of the FEMA Region have been, or are expected to be, overwhelmed. Three ERT-Ns have been established.

Emergency Support Function: In the FRP, a functional area of response activity established to facilitate the delivery of Federal assistance required during the immediate response phase of a disaster to save lives, protect property and public health, and to maintain public safety. ESFs represent those types of Federal assistance which the State will most likely need because of the impact of a catastrophic or significant disaster on its own resources and response capabilities, or because of the specialized or unique nature of the assistance required. ESF missions are designed to supplement State and local response efforts.

Emergency Support Team: An interagency group operating from FEMA headquarters. The EST oversees the national-level response support effort under the FRP and coordinates activities with the ESF primary and support agencies in supporting Federal requirements in the field.

Evacuation: Organized, phased, and supervised dispersal of people from dangerous or potentially dangerous areas.

  • Spontaneous Evacuation. Residents or citizens in the threatened areas observe an emergency event or receive unofficial word of an actual or perceived threat and without receiving instructions to do so, elect to evacuate the area. Their movement, means, and direction of travel is unorganized and unsupervised.
  • Voluntary Evacuation. This is a warning to persons within a designated area that a threat to life and property exists or is likely to exists in the immediate future. Individuals issued this type of waning or order are NOT required to evacuate, however it would be to their advantage to do so.
  • Mandatory or Directed Evacuation. This is a warning to persons within the designated area that an imminent threat to life and property exists and individuals MUST evacuate in accordance with the instructions of local officials.

Evacuees: All persons removed or moving from areas threatened or struck by a disaster.

Exposure (Radiological): A quantitative measure of gamma or x-ray radiation at a certain place based on its ability to produce ionization in air.

Exposure Rate (Radiological): The amount of ionizing radiation to which an individual would be exposed or which he or she would receive per unit of time.

Federal Coordinating Officer: The person appointed by the President to coordinate Federal assistance in a Presidentially declared emergency or major disaster.

Field Assessment Team: A small team of pre-identified technical experts that conduct an assessment of response needs (not a PDA) immediately following a disaster. The experts are drawn from FEMA, other agencies and organizations–such as the U.S. Public Health Service, U.S. Army Corps of Engineers, U.S. Environmental Protection Agency, and the American Red Cross–and the affected State(s). All FAsT operations are joint Federal/State efforts.

Flash Flood: Follows a situation in which rainfall is so intense and severe and runoff so rapid that it precludes recording and relating it to stream stages and other information in time to forecast a flood condition.

Flood: A general and temporary condition of partial or complete inundation of normally dry land areas from overflow of inland or tidal waters, unusual or rapid accumulation or runoff of surface waters, or mudslides/mudflows caused by accumulation of water.

Governor’s Authorized Representative: The person empowered by the Governor to execute, on behalf of the State, all necessary documents for disaster assistance.

Hazard Mitigation: Any action taken to reduce or eliminate the long-term risk to human life and property from hazards. The term is sometimes used in a stricter sense to mean cost-effective measures to reduce the potential for damage to a facility or facilities from a disaster event.

Hazardous Material: Any substance or material that when involved in an accident and released in sufficient quantities, poses a risk to people’s health, safety, and/or property. These substances and materials include explosives, radioactive materials, flammable liquids or solids, combustible liquids or solids, poisons, oxidizers, toxins, and corrosive materials.

High-Hazard Areas: Geographic locations that for planning purposes have been determined through historical experience and vulnerability analysis to be likely to experience the effects of a specific hazard (e.g., hurricane, earthquake, hazardous materials accident, etc.) resulting in vast property damage and loss of life.

Hurricane: A tropical cyclone, formed in the atmosphere over warm ocean areas, in which wind speeds reach 74 miles per hour or more and blow in a large spiral around a relatively calm center or “eye”. Circulation is counter-clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

Incident Command System: A standardized organizational structure used to command, control, and coordinate the use of resources and personnel that have responded to the scene of an emergency. The concepts and principles for ICS include common terminology, modular organization, integrated communication, unified command structure, consolidated action plan, manageable span of control, designated incident facilities, and comprehensive resource management.

Joint Information Center: A central point of contact for all news media near the scene of a large-scale disaster. News media representatives are kept informed of activities and events by public information officials who represent all participating Federal, State, and local agencies that are collocated at the JIC.

Joint Information System: Under the FRP, connection of public affairs personnel, decision-makers, and news centers by electronic mail, fax, and telephone when a single FederalState-local JIC is not a viable option.

Mass Care: The actions that are taken to protect evacuees and other disaster victims from the effects of the disaster. Activities include providing temporary shelter, food, medical care, clothing, and other essential life support needs to those people that have been displaced from their homes because of a disaster or threatened disaster.

Nuclear Detonation: An explosion resulting from fission and/or fusion reactions in nuclear material, such as that from a nuclear weapon.

Public Information Officer: A Federal, State, or local government official responsible for preparing and coordinating the dissemination of emergency public information.

Preliminary Damage Assessment: A mechanism used to determine the impact and magnitude of damage and the resulting unmet needs of individuals, businesses, the public sector, and the community as a whole. Information collected is used by the State as a basis for the Governor’s request for a Presidential declaration, and by FEMA to document the recommendation made to the President in response to the Governor’s request. PDAs are made by at least one State and one Federal representative. A local government representative familiar with the extent and location of damage in the community often participates; other State and Federal agencies and voluntary relief organizations also may be asked to participate, as needed.

Radiation Sickness: The symptoms characterizing the sickness known as radiation injury, resulting from excessive exposure of the whole body to ionizing radiation.

Radiological Monitoring: The process of locating and measuring radiation by means of survey instruments that can detect and measure (as exposure rates) ionizing radiation.

Recovery: The long-term activities beyond the initial crisis period and emergency response phase of disaster operations that focus on returning all systems in the community to a normal status or to reconstitute these systems to a new condition that is less vulnerable.

Regional Operating Center: The temporary operations facility for the coordination of Federal response and recovery activities, located at the FEMA Regional Office (or Federal Regional Center) and led by the FEMA Regional Director or Deputy Director until the DFO becomes operational. Once the ERT-A is deployed, the ROC performs a support role for Federal staff at the disaster scene.

Resource Management: Those actions taken by a government to: identify sources and obtain resources needed to support disaster response activities; coordinate the supply, allocation, distribution, and delivery of resources so that they arrive where and when most needed; and maintain accountability for the resources used.

Secondary Hazard: A threat whose potential would be realized as the result of a triggering event that of itself would constitute an emergency. For example, dam failure might be a secondary hazard associated with earthquakes.

Standard Operating Procedure: A set of instructions constituting a directive, covering those features of operations which lend themselves to a definite, step-by-step process of accomplishment. SOPs supplement EOPs by detailing and specifying how tasks assigned in the EOP are to be carried out.

State Coordinating Officer: The person appointed by the Governor to coordinate State, Commonwealth, or Territorial response and recovery activities with FRPrelated activities of the Federal Government, in cooperation with the FCO.

State Liaison: A FEMA official assigned to a particular State, who handles initial coordination with the State in the early stages of an emergency.

Storm Surge: A dome of sea water created by the strong winds and low barometric pressure in a hurricane that causes severe coastal flooding as the hurricane strikes land.


Terrorism: The use of–or threatened use of–criminal violence against civilians or civilian infrastructure to achieve political ends through fear and intimidation, rather than direct confrontation. Emergency management is typically concerned with the consequences of terrorist acts directed against large numbers of people (as opposed to political assassination or hijacking, which may also be considered “terrorism”).

Tornado: A local atmospheric storm, generally of short duration, formed by winds rotating at very high speeds, usually in a counter-clockwise direction. The vortex, up to several hundred yards wide, is visible to the observer as a whirlpool-like column of winds rotating about a hollow cavity or funnel. Winds may reach 300 miles per hour or higher.


Tsunami: Sea waves produced by an undersea earthquake. Such sea waves can reach a height of 80 feet and can devastate coastal cities and low-lying coastal areas.

Warning: The alerting of emergency response personnel and the public to the threat of extraordinary danger and the related effects that specific hazards may cause. A warning issued by the NWS (e.g., severe storm warning, tornado warning, tropical storm warning) for a defined area indicates that the particular type of severe weather is imminent in that area.

Watch: Indication by the NWS that, in a defined area, conditions are favorable for the specified type of severe weather (e.g., flash flood watch, severe thunderstorm watch, tornado watch, tropical storm watch).
Indication by the NWS that, in a defined area, conditions are favorable for the specified type of severe weather (e.g., flash flood watch, severe thunderstorm watch, tornado watch, tropical storm watch).