Glossary

There are often unfamiliar terms and acronyms that are used if you are involved in FEMA appeals or a floodplain management situation. The glossary here may be helpful as you proceed.

AADPA

FEMA acronym for Assistant Associate Director for Public and Intergovernmental Affairs

ACHP

Advisory Council on Historic Preservation

ADA

Americans with Disabilities Act

ADAMS

FEMA’s Automated Disaster Assistance Management System

Advanced Weather Interactive Processing System (AWIPS)

The computerized system that processes NEXRAD and ASOS data received at National Weather Service Forecast Offices

Advisory

A message from the National Hurricane Center in Miami giving warning information with details on tropical cyclone location, intensity and movement, and precautions that should be taken. The advisory will contain a summary of all warnings in effect.

AE

Aeromedical Evacuation

AEC

Agency Emergency Coordinators

AECE

Aeromedical Evacuation Control Element

Aerial Reconnaissance Weather Officer (ARWO)

The flight meteorologist for weather reconnaissance flights into a tropical cyclone

AES

Aeromedical Evacuation System

AFOS

Automation of Field Operations and Services

ALCC

Airlift Control Center

AMC

Air Mobility Command, U.S. Air Force

AMS

Aerial Measuring System

Anemometer

An instrument that measures the speed or force of the wind

ANRC

American National Red Cross

AOC

Army Operations Center, Pentagon

APE

Area of Potential Effect

Applicant (for FEMA Grants)

The state agency, local government or eligible private nonprofit organization which submits a request for assistance to the State; the State is the Grantee of all federal grants for public assistance and administers subgrants made to applicants.

Applicant Liaison (Liaison)

A State government customer representative responsible for providing applicants with state-specific information and documentation requirements. The Liaison works closely with the Public Assistance Coordinator to provide any assistance the applicant may require.

ARC

American Red Cross

ARES

Amateur Radio Emergency Services

ARRL

American Radio Relay League

ARS

Agricultural Research Service

ARWO

Aerial Reconnaissance Weather Office

ASCE

American Society of Civil Engineers

ASD

Assistant Secretary of Defense

ASDSO

Association of State Dam Safety Officials

ASOS

Automated Surface Observing Systems

Atmospheric Pressure

The pressure exerted by the atmosphere at a given point. Its measurement can be expressed in several ways, such as in millibars and in inches or millimeters of mercury (Hg). Also known as barometric pressure.

AUTODIN

Automatic Digital Network

Automated Surface Observing Systems (ASOS) — weather service

A collection of automated weather instruments that collect data. They perform surface-based observations from places that do not have a human observer, or that do not have an observer 24 hours a day.

Automation of Field Operations and Services (AFOS) — weather service

The computer system that links National Weather Service offices together for weather data transmission

AUTOVON

Automatic Voice Network

AWIPS

Advanced Weather Interactive Processing System

Barometer

An instrument for determining the pressure of the atmosphere

Best Track

A subjectively smoothed path, versus a precise and very erratic fix-to-fix path, used to represent tropical cyclone movement. It is based on an assessment of all available data.

BFE

Base Flood Elevation

BIA

Bureau of Indian Affairs

BIFC

Boise Interagency Fire Center

BLM

Bureau of Land Management

BMP

Best Management Practices

BOR

Bureau of Reclamation

BPA

Blanket Purchase Agreement

Breach

An opening through the dam resulting in partial or total failure of the dam

C&D

Construction and Demolition

CAA

Clean Air Act

Cape Verde Islands

A group of volcanic islands in the eastern Atlantic Ocean off the coast of West Africa. A “Cape Verde hurricane” originates in this area.

CAR

Capability Assessment for Readiness

CARCAH

Chief, Aerial Reconnaissance Coordination, All Hurricanes. The 53rd Weather Reconnaissance Squadron’s Air Force Reserve civilians who bridge the gap between the Hurricane Specialists at NHC and the flying squadron. Each day, they publish the Tropical Cyclone Plan of the Day.

Case Management

A systems approach to provision of equitable and fast service to applicants for disaster assistance. Organized around the needs of the applicant, the system consists of a single point of coordination, a team of on-site specialists, and a centralized, automated filing system.

Case Management File

A centralized data bank of all applicant activities. Data entered into this bank creates a chronological history of everything that has taken place with an applicant from the time they apply for assistance until they have received all monies and their file has been closed.

CAT

Crisis Action Team

CATEX

Categorical Exclusion

CBIRF

Chemical, Biological Incident Response Force

CBRA

Coastal Barrier Resources Act

CBRNE

Chemical, Biological, Radiological, Nuclear or High-Yield Explosive

CBRS

Coastal Barrier Resources System

CC

Crisis Counseling

CCC

Commodity Credit Corporation

CCO

Consultation Coordination Officer

CCP

Casualty Collection Point

CDBG

Community Development Block Grant

CDC

Centers for Disease Control, U.S. Public Health Service

CDRG

Catastrophic Disaster Response Group

Back to top

Center

The vertical axis or core of a tropical cyclone. It is usually determined by cloud vorticity patterns, wind and/or pressure distributions.

Center/Vortex Fix

The location of the center of a tropical or subtropical cyclone obtained by reconnaissance aircraft penetration, satellite, radar, or synoptic data

Central North Pacific Basin

The region north of the Equator between 140W and the International Dateline. The Central Pacific Hurricane Center (CPHC) in Honolulu, Hawaii is responsible for tracking tropical cyclones in this region.

CEQ

Council of Environmental Quality

CERCLA

Comprehensive Environmental Resource Compensation and Liability Act

CFR

Code of Federal Regulations

CIA

Central Intelligence Agency

CIAO

Critical Infrastructure Assurance Office

CINC

Commander-In-Chief

CIP

Critical Infrastructure Protection

CJCS

Chairman of the Joint Chiefs of Staff

CLOMA

Conditional Letter of Map Amendment

CLOMR

Conditional Letter of Map Revision

CLOMR-F

Conditional Letter of Map Revision Based on Fill

Closest Point of Approach

Point where hurricane eye makes closest contact to shore without actually making landfall

CM

Consequence Management

CMAT

Consequence Management Advisory Team

CMT

Crisis Management Team

Coastal Flood Warning

A warning that significant wind-forced flooding is expected along low-lying coastal areas if weather patterns develop as forecast

Coastal Flood Watch

An announcement that significant wind-forced flooding is expected along low-lying coastal areas if weather patterns develop as forecast

COG

Continuity of Government

Cold Front

The leading edge of an advancing cold air mass that is underrunning and displacing the warmer air in its path. Generally, with the passage of a cold front, the temperature and humidity decrease, the pressure rises, and the wind shifts (usually from the southwest to the northwest in the Northern Hemisphere). Precipitation is generally at and/or behind the front, and with a fast-moving system, a squall line may develop ahead of the front. See occluded front and warm front.

Comprehensive EAP Exercise

An in-depth exercise of an EAP that involves the interaction of the dam owner with the state and local emergency management agencies in a stressful environment with time constraints. Functional and full-scale EAP exercises are considered comprehensive EAP exercises.

CONPLAN

Concept of Operations Plan

Consequences

Potential loss of life or property damage downstream of a dam caused by floodwaters released at the dam or by waters released by partial or complete failure of the dam. Includes effects of landslides upstream of the dam on property located around the reservoir.

CONUS

Continental United States

CONUSA

Continental United States Army

Convection

Atmospheric motions in the vertical direction resulting from surface heating and the subsequent rising of warm air. This lifting mechanism is capable of generating the rising motions necessary for clouds and precipitation to form.

Convergence

Wind movement that results in a horizontal net inflow of air into a particular region. Convergent winds at lower levels are associated with upward motion. Contrast with divergence.

COOP

Continuity of Operations

Cost Estimating Format (CEF)

A forward pricing methodology for estimating the total cost of repair for large permanent projects, by use of construction industry standards. The format uses a base cost estimate and design and construction contingency factors, applied as a percentage of the base cost.

CRS

Community Rating System

CS

Customer Service

CSEPP

Chemical Stockpile Emergency Preparedness Program

CTA

Combined Travel Authorization

CWA

Clean Water Act

CWS

Checkwriter System

Cyclone

An atmospheric circulation (low-pressure system) with rotating and converging winds, in which the center has a relative pressure minimum. It usually has a diameter of 2000 to 3000 kilometers. When developing, a cyclone typically consists of a warm front pushing northward and a cold front pushing southward with the center of low pressure (cyclone center) located at the junction of the two fronts. Cyclones in the Northern Hemisphere rotate counter-clockwise while Southern Hemisphere cyclones rotate clockwise.

DAC

Disaster Application Center

DAE

Disaster Assistance Employee

Dam Failure

Catastrophic type of failure characterized by the sudden, rapid and uncontrolled release of impounded water. It is recognized that there are lesser degrees of failure and that any malfunction or abnormality outside the design assumptions and parameters which adversely affect a dam’s primary function of impounding water is properly considered a failure. Such lesser degrees of failure can progressively lead to or heighten the risk of a catastrophic failure. They are, however, normally amendable to corrective action.

DAMAGES

Disaster Assistance Management Accountability System

DAMO-DS

Domestic Strategy and Support Directorate

Data Buoys

Buoys placed throughout the Gulf of Mexico and along the Atlantic and Pacific coasts of the United States that relay information on air and water temperature, wind speed, air pressure and wave conditions via radio signals

DCE

Defense Coordinating Element

DCO

Defense Coordinating Officer

DDRM

Deputy Disaster Recovery Manager

Declaration

The act based on the President’s decision that a major disaster qualifies for federal assistance under the Stafford Act

Deepening

Describes a decrease in the central pressure of a low-pressure system or an area of cyclonic circulation. Although it usually describes the action of a pressure system on a constant pressure chart, it also means a surface low is increasing in cyclonic circulation and acquiring more energy. It is the opposite of filling.

Depression

In meteorology, another name for an area of low pressure, a low or trough. It also applies to a stage of tropical cyclone development and is known as a tropical depression to distinguish it from other synoptic features.

DEST

Domestic Emergency Support Team

DFCO

Deputy Federal Coordinating Officer

DFO

Disaster Field Office

DHS

Department of Homeland Security

DHS-BTS

Department of Homeland Security, Border and Transportation Security Directorate

DHS-EPR

Department of Homeland Security, Emergency Preparedness and Response Directorate

DHS-IAIP

Department of Homeland Security, Information Analysis and Infrastructure Protection Directorate

DIA

Defense Intelligence Agency

DISC

Disaster Information System Clearinghouse

Disturbance

Can apply to a low or cyclone that is small in size and influence. It can also apply to an area that is exhibiting signs of cyclonic development, or to a stage of tropical cyclone development, known as a tropical disturbance to distinguish it from other synoptic features.

DMAT

Disaster Medical Assistance Team

DMORT

Disaster Mortuary Response Team, National Disaster Medical System

DMTF

Debris Management Task Force

DOC

Department of Commerce

DOD

Department of Defense

DoDD

Department of Defense Directive

DoDI

Department of Defense Instruction

DOE

Department of Energy

DOI

Department of the Interior

DOJ

Department of Justice

DOL

Department of Labor

DOMS

Directorate of Military Support, Department of Defense

Doppler Radar

Weather radar that measures direction and speed of a moving object, such as drops of precipitation, by determining whether atmospheric motion is horizontally toward or away from the radar. Using the Doppler effect, it measures the velocity of particles.

DOS

Department of State

DOT

Department of Transportation

DPA

Defense Production Act of 1950

DPAS

Defense Priorities and Allocation System

DPW

Department of Public Works

DRC

Disaster Recovery Center

DRD

Deputy Regional Director

DRF

Disaster Relief Fund

DRM

Disaster Recovery Manager

DSPMT

Dam Safety Program Management Tools

DSPPM

Dam Safety Program Performance Measures

DSR

Damage Survey Report

DTRA

Defense Threat Reduction Agency

DWI

Disaster Welfare Inquiry

EA

Environmental Assessment

EAD

Executive Associate Director, Response and Recovery Directorate (FEMA)

EAP

Emergency Action Plan

EAP Exercise

An activity designed to promote emergency preparedness; test or evaluate EAPs, procedures, or facilities; train personnel in emergency management duties; and demonstrate operational capability. Exercises consist of the performance of duties, tasks, or operations very similar to the way they would be performed in a real emergency. However, the exercise performance is in response to a simulated event.

EAS

Emergency Alert System

Easterly Wave

An inverted, migratory wave-like disturbance or trough in the tropical region that moves from east to west, generally creating only a shift in winds and rain. The low-level convergence and associated convective weather occur on the eastern side of the wave axis. Normally, it moves slower than the atmospheric current in which it is embedded and is considered a weak trough of low pressure. It is often associated with possible tropical cyclone development and is also known as a tropical wave.

Eastern North Pacific Basin

The region north of the Equator east of 140W. The National Hurricane Center in Miami, Florida, is responsible for tracking tropical cyclones in this region.

EBS

Emergency Broadcast System

EC

Emergency Coordinator

ECS

Emergency Communications Staff

EEI

Essential Elements of Information

EENET

Emergency Education Network

EICC

Emergency Information and Coordination Center (FEMA)

EIMA

Emergency Information and Media Affairs

EIS

Environmental Impact Statement

EJ

Environmental Justice

El Nino

A warming of the Pacific Ocean currents along the coasts of Peru and Ecuador near the Equator that is generally associated with dramatic changes or shifts in the weather patterns of the region. A major El Nino event generally occurs every 3 to 7 years and is associated with changes in the weather patterns worldwide, including hurricanes.

ELO

Environmental Liaison Officer

EM

Emergency Management

EMAC

Emergency Management Assistance Compact

Emergency

Any occasion or instance for which, in the determination of the President, Federal Assistance is needed to supplement state and local efforts and capabilities to save lives and to protect property and public health and safety, or to lessen or avert the threat of a catastrophe in any part of the United States.

Emergency Broadcast System

A federally established network of commercial radio stations that voluntarily provide official emergency instructions or directions to the public during an emergency.

Emergency Alert System (EAS)

A system designed to permit government officials to issue up-to-date and continuous emergency information and instructions to the public in case of a threatened or actual emergency. It is replacing the Emergency Broadcast System.

Emergency Management Agency

The state and local agencies responsible for emergency operations, planning, mitigation, preparedness, response and recovery for all hazards. Names of emergency management agencies include: Division of Emergency Management, Comprehensive Emergency Management, Disaster Emergency Services, Civil Defense Agency, Emergency and Disaster Services.

Emergency Operations Center (EOC)

The location or facility where responsible officials gather during an emergency to direct and coordinate emergency operations, to communicate with other jurisdictions and with field emergency forces, and to formulate protective action decisions and recommendations during an emergency.

Emergency Public Information

Information disseminated primarily, but not unconditionally, at the time of an emergency including actions, instructions and direct orders.

Emergency Public Shelter

Generally a public school or other such structure designated by county or city officials as a place of refuge. A volunteer group such as the American Red Cross or Salvation Army usually manages a shelter.

Emergency Work

Work which must be done immediately to save lives and to protect improved property, public health and safety, or to avert or lessen the threat of a major disaster. Emergency work frequently includes clearance and removal of debris and temporary restoration of essential public facilities and services.

EMI

Emergency Management Institute

EMPA

Emergency Management Planning and Assistance

EMPG

Emergency Management Performance Grant

EMS

Emergency Medical Services

EMWIN

Emergency Manager’s Weather Information Center

EO

Executive Order

EOC

Emergency Operations Center

EOP

Emergency Operations Plan

EPA

Environmental Protection Agencies

EPCRA

Emergency Planning and Community Right-to-Know Act

EPIC

Emergency Public Information and Communications Advisory Committee

EPLO

Emergency Preparedness Liaison Officer

EPRI

Electric Power Research Institute

Equator

The geographic circle at 0 degrees latitude on the earth’s surface. It is an equal distance from the North and South Poles and divides the Northern Hemisphere from the Southern.

ER

Emergency Relief (FHWA Assistance Program)

ERB

Economic Resources Board

ERM

Elevation Reference Mark

ERT

Emergency Response Team

ERT-A

Advance Element of the Emergency Response Team (FEMA)

ESA

Endangered Species Act

ESDP

Engineering Study Data Package

ESF

Emergency Support Function

EST

Emergency Support Team (FEMA)

Evacuation Time

The lead-time that a populated coastal area must have to safely relocate all residents of vulnerable areas from an approaching hurricane. This time can also be perceived as the necessary amount of time between the local official evacuation order and the arrival of sustained gale force winds (40 mph) and/or flooding.

Explosive Deepening

A decrease in the minimum sea-level pressure of a tropical cyclone of 2.5 mb/hr for at least 12 hours or 5 mb/hr for at least six hours

Extent of Evacuation

The identification of vulnerable people who must evacuate based on estimated damage and/or homes susceptible to hurricane force winds

Extratropical

A term used in advisories and tropical summaries to indicate that a cyclone has lost its tropical characteristics. The term implies both poleward displacement of the cyclone and the conversion of the cyclone’s primary energy source from the release of latent heat of condensation to baroclinic (the temperature contrast between warm and cold air masses) processes. It is important to note that cyclones can become extratropical and still retain winds of hurricane or tropical storm force.

Extratropical Cyclone

A cyclone in the middle and high latitudes, often being 2000 kilometers in diameter and usually containing a cold front that extends toward the equator for hundreds of kilometers. These cyclones form outside the tropics, the center of storm is colder than the surrounding air, and have fronts and the strongest winds in the upper atmosphere.

Eye

The center of a tropical storm or hurricane characterized by a roughly circular area of light winds and rain-free skies and the lowest pressure. An eye will usually develop when the maximum sustained wind speeds exceed 78 mph. It can range in size from as small as 5 miles to up to 60 miles (20-50 km) but the average size is 20 miles. In general, when the eye begins to shrink in size, the storm is intensifying.

Eye Wall

An organized band of convection surrounding the eye, or center, of a tropical cyclone. It contains cumulonimbus clouds, severest thunderstorms, heaviest precipitation and strongest winds.

FAA

Federal Aviation Administration

Facility

Any publicly or privately owned building, works, system or equipment, built or manufactured, or an improved and maintained natural feature. Land used for agricultural purposes is not a “facility.”

FARS

Financial Accounting and Reporting System

FAST

Field Assessment Team

FAX

Facsimile

FBFM

Flood Boundary and Floodway Map

FBI

Federal Bureau of Investigation

FCC

Federal Communications Commission

FCM

Federal Communications Manager

FCO

Federal Coordinating Officer

FDA

Food and Drug Administration

FDPA

Flood Disaster Protection Act

FDT

Floodway Data Table

Feeder Bands

In tropical parlance, the lines or bands of thunderstorms that spiral into and around the center of a tropical system. Also known as outer convective bands, a typical hurricane may have three or more of these bands. They occur in advance of the main rain shield and are usually 40 to 80 miles apart. In thunderstorm development, they are the lines or bands of low-level clouds that move or feed into the updraft region of a thunderstorm.

FEMA

Federal Emergency Management Agency

FERC

Federal Energy Regulatory Commission

FESC

Federal Emergency Support Coordinator

FFED

Final Flood Elevation Determination

FHBM

Flood Hazard Boundary Map

FHWA

Federal Highway Administration

FIA

Federal Insurance Administration

Filling

Used in describing the history of a low-pressure system or an area of cyclonic circulation, it means an increase in the central pressure of the system. Although it usually describes the action of a pressure system on a constant pressure chart, it also means a surface low is decreasing in cyclonic circulation and losing its characteristics. The opposite of deepening.

FIMA

Federal Insurance and Mitigation Administration

FIRM

Flood Insurance Rate Map

FIS

Flood Insurance Study

FISA

Foreign Intelligence Surveillance Act

Flood Hydrograph

A graph showing, for a given point on a stream, the discharge, height or other characteristic of a flood with respect to time.

Flood Plain

Any land area susceptible to being inundated by water from any source. Normally the regulatory flood plain is characterized by the designation “100-year,” meaning there is a 1% chance of flooding per year. The flood plain is often referred to as flood prone areas.

Flood Routing

A process of determining progressively over time the amplitude of a flood wave as it moves past a dam or downstream to successive points along a river or stream.

Flood Stage

The level of a river or stream where overflow onto surrounding areas can occur

Flood Warning

The expected severity of flooding (minor, moderate or major) as well as where and when the flooding will begin

Flooding

A general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal water, or rapid accumulation or runoff of surface waters from any source

FMA

Flood Mitigation Assistance

FNS

Food and Nutrition Services

FOC

FEMA Operations Center

FOIA

Freedom of Information Act

FONSI

Finding of No Significant Impact

Force Account

An applicant’s own labor forces and equipment

Forecast

A statement of expected future occurrences. Weather forecasting includes the use of objective models based on certain atmospheric parameters, along with the skill and experience of a meteorologist. Also called a prediction.

Forward Speed

The rate of movement (propagation) of the hurricane eye in miles per hour or knots

FRERP

Federal Radiological Emergency Response Plan

Front

The boundary between two dissimilar air masses

FRP

Federal Response Plan

FS

Forest Service

FSN

FEMA Switch Network

FSS

Federal Supply Service

FTCA

Federal Tort Claims Act

FTE

Full-Time Equivalent

FTS

Federal Telecommunications Equipment

Fujiwhara Effect

A binary interaction where tropical cyclones within a certain distance (300-750 nautical miles depending on the sizes of the cyclones) of each other begin to rotate about a common midpoint

FWPCA

Federal Water Pollution Control Act

FWS

U.S. Fish and Wildlife Service

FY

Fiscal Year

Gale Warning

A warning of 1-minute sustained surface winds in the range 39 to 54 mph (34 to 47 knots) inclusive, either predicted or occurring not directly associated with tropical cyclones

GAR

Governor’s Authorized Representative

GC

FEMA’s Office of General Counsel

Geostationary Operational Environmental Satellites (GOES)

Family of NWS weather satellites, which orbit 22,300 miles above the earth and maintain a velocity that allow them to remain over a fixed place above the equator. Images are available to forecasters every 30 minutes.

GIS

Geographic Information System

GPS

Global Positioning System

Greenwich Mean Time (GMT)

The name of the twenty-four hour time scale that is used throughout the scientific and military communities. Standard Time begins at Greenwich, England, which is the Prime Meridian of Longitude. The globe is divided into twenty-four (24) time zones of 15 degrees of arc, or one hour in time apart. To the east of this meridian, time zones are numbered 1 to 12 and prefixed with a minus (-), while to the west, the time zones are also numbered 1 through 12 but prefixed with a plus (+). Other names for this time measurement are Universal Time Coordinate (UTC) and Zulu (Z).

GSA

General Services Administration

H&H

Hydraulics and Hydrology

Hazard Mitigation

Any cost-effective measure that will reduce the potential for damage to a facility from a disaster event

Hazard Potential

A situation which creates the potential for adverse consequences such as loss of life, property damage or other adverse impacts. Impacts may be for a defined area downstream of a dam from flood-waters released through spillways and outlet works of the dam, or waters released by partial or complete failure of the dam. They may also be for an area upstream of the dam from effects of backwater flooding or effects of landslides around the reservoir perimeter.

HAZMAT

Hazardous materials

HAZUS

Hazards United States

Headwater

The water immediately upstream from a dam. The water surface elevation varies due to fluctuations in inflow and the amount of water passed through the dam.

HES

Hurricane Evacuation Study

HF

High Frequency

HHR

Health and Human Resources

HHS

Department of Health and Human Services

HHW

Household hazardous waste

High Wind Advisory

Announcement issued by the National Weather Service for sustained winds exceeding 25 mph (19 knots)

High Wind Watch/Warning

Issued by the National Weather Service when either of the following occurs or is expected to occur in the near term: 1) Sustained surface winds (1-minute average) of 40 mph (35 knots) or greater, lasting for 1 hour or longer; or 2) Sustained winds or gusts of 58 mph (50 knots) or greater for any duration.

High-Pressure System

An area of relative pressure that has diverging winds and a rotation opposite to the earth’s rotation. This is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. Also known as an anticyclone, it is the opposite of an area of low pressure or a cyclone.

HIPAA

Health Insurance Portability and Accountability Act of 1996

HM

Hazard mitigation

HMGP

Hazard Mitigation Grant Program

HMRU

Hazardous Materials Response Unit

HQ

Headquarters

HSAS

Homeland Security Advisory System

HSC

Homeland Security Council

HSPD

Homeland Security Presidential Directive

HUD

U.S. Department of Housing and Urban Development

Humidity

The amount of water vapor in the air

Hurricane

A tropical cyclone in the Northern Hemisphere with sustained winds of 74 mph (64 knots) or greater in the North Atlantic Ocean, Caribbean Sea or Gulf of Mexico. These winds blow in a large spiral around a relatively calm center of extremely low pressure known as the eye. Around the rim of the eye, winds may gust to more than 200 miles per hour. The entire storm, which can be up to 340 miles (550 kilometers) in diameter, and dominates the lower atmosphere and ocean surface over tens of thousands of square miles. Hurricanes draw their energy from the warm surface water of the tropics (usually above 27 Celsius) and latent heat of condensation, which explains why hurricanes dissipate rapidly once they move over cold water or large land masses.

Hurricane Advisory

Notice, issued by the National Hurricane Center and numbered consecutively for each storm, describing the present and forecasted position and intensity of a hurricane. Advisories are issued at six-hour intervals at midnight, 6 am, noon and 6 pm, Eastern Daylight Time. Bulletins provide additional information. Each message gives the name, eye position, intensity and forecast movement of the storm.

Hurricane Clips

A structural bracing device used on the installation of roofs which reinforce the joints of a house and give a stronger connection to wood-to-wood roofing trusses than just nails. In many coastal communities, hurricane clips are enforced as a code restriction for new homes.

Hurricane Eye

The relatively calm area near the center of the storm. In this area, winds are light and the sky is often partly covered by clouds.

Hurricane Eye Landfall

When the eye, or physical center of the hurricane, reaches the coastline from the hurricane’s approach over water.

Hurricane Hunters

The 53rd Weather Reconnaissance Squadron of the U.S. Air Force Reserve, based out of Keesler Air Force Base in Biloxi, Mississippi. As a part of the 403rd Air Wing, the crew flies Lockheed WC-130 aircraft into tropical storms and hurricanes to gather meteorological data for the National Hurricane Center.

Hurricane Liaison Team

A team of FEMA, NWS, state and local emergency management officials which respond to the National Hurricane Center prior to the landfall of a hurricane in the Atlantic Ocean, Caribbean Sea or Gulf of Mexico. The primary purpose of the team is to assist in coordinating the latest advisories from the NHC to the federal, state and local emergency management agencies.

Hurricane Local Statement

A public release prepared by local National Weather Service Field Offices in or near a threatened area, giving specific details for its county/parish warning area on: 1) weather conditions; 2) evacuation decisions made by local officials; and 3) other precautions necessary to protect life and property.

Hurricane Path or Track

Line of movement (propagation) of the eye through an area

Hurricane Season

The portion of the year having a relatively high incidence of hurricanes. The hurricane season in the Atlantic, Caribbean and Gulf of Mexico runs from June 1 to November 30. The hurricane season in the Eastern Pacific basin runs from May 15 to November 30. The hurricane season in the Central Pacific basin runs from June 1 to November 30.

Hurricane Warning

A warning added to a hurricane advisory that sustained winds of 74 mph (64 knots) or higher associated with a hurricane are expected in a specified coastal area within 24 hours or less. A hurricane warning can remain in effect when dangerously high water or a combination of dangerously high water and exceptionally high waves continue, even though winds may be less than hurricane force. A warning is used to inform the public and marine interests of the storm’s location, intensity and movement. The NHC chooses a distance of approximately 300 miles.

Hurricane Watch

An announcement added to a hurricane advisory that hurricane conditions pose a possible threat to a specified coastal area within 36 hours. A watch is used to inform the public and marine interests of the storm’s location, intensity and movement.

Hurricane/Tropical Storm Probabilities

Issued to allow citizens to realistically assess the threat of a hurricane or tropical storm hitting their community. The probabilities are defined as the chance in percent that the center of the storm will pass within approximately 65 miles of 44 selected locations from Brownsville, Texas, to Eastport, Maine.

IA

Individual Assistance

IAO

Individual Assistance Officer

IBWC

International Boundary and Water Commission

ICC

Increased Cost of Compliance

ICODS

Interagency Committee on Dam Safety

ICOLD

International Commission on Large Dams

ICS

Incident Command System

IFG

Individual and Family Grant

IFMIS

Integrated Financial Management Information System

IG

FEMA Office of Inspector General

IIMG

Interagency Incident Management Group

Immediate Needs Funding (INF)

An advance of grant funds to assist with payment of emergency work within the first 60 days after a disaster strikes. The amount of funding is normally 50% of the federal share of emergency costs as identified during the preliminary damage assessment.

Improved Property

A structure, facility or item of equipment that was built, constructed or manufactured. Land used for agricultural purposes is not improved property.

IMS

Information Management System

Inches of Mercury (Hg)

The name comes from the use of mercurial barometers that equate the height of a column of mercury with air pressure. One inch of mercury is equivalent to 33.86 millibars or 25.40 millimeters.

Inflow Design Flood

The flood flow above which the incremental increase in water surface elevation due to failure of a dam or other water impounding structure is no longer considered to present an unacceptable threat to downstream life or property. Also refers to the flood hydrograph used in the design of a dam and its appurtenant works particularly for sizing the spillway and outlet works and for determining maximum temporary storage, height of dam and freeboard requirements.

Inland High Wind Warning for Hurricane Force Winds

Announcement issued when winds of 74 mph (64 knots) or greater are predicted to occur within 12 hours

Inland High Wind Watch for Hurricane Force Winds

Announcement issued when winds of 74 mph (64 knots) or greater are predicted to occur within 24 hours

INS

Immigration and Naturalization Service

Instability

Occurs when a rising air parcel becomes less dense than the surrounding air. Since its temperature will not cool as rapidly as the surrounding environment, it will continue to rise on its own. Contrasts with stable air.

Intertropical Convergence Zone (ITCZ)

The axis dividing the southeast trades from the northeast trades, toward which the surface winds tend to converge. The easterly trade winds of both hemispheres converge at an area near the equator called the Intertropical Convergence Zone (ICTZ), producing a narrow band of clouds and thunderstorms that encircle portions of the globe.

Inundation Map

Delineates areas that would be flooded as a result of a dam failure

ISAC

Information Sharing and Analysis Center

ISG

White House Incident Support Group

Isobar

The line drawn on a weather map connecting points of equal barometric pressure

IT

Information technology

ITS

FEMA’s Information Technology Services Directorate

Jet stream

Relatively strong winds concentrated within a narrow current in the atmosphere

JFHQ

Joint Forces Headquarters (Homeland Security)

JFO

Joint Field Office

JIC

Joint Information Center

JIISE

Joint Interagency Intelligence Support Element

JOC

Joint Operations Center

JTTF

Joint Terrorism Task Force

Kickoff Meeting

The initial meeting between an applicant and the Public Assistance Coordinator. At this working session, the applicant turns in a list of damages and receives comprehensive information about the Public Assistance program and detailed guidance for their specific circumstances.

KM

Kilometers

Knot

A unit for the measurement of speed in the nautical system. It is the nautical “miles per hour.”

LAG

Lowest adjacent grade (to a structure)

LAN

Local Area Network

Landfall

The term used to describe where the hurricane eye actually passes over land, usually used to describe the continental States rather than islands in the Caribbean.

Large Project

An eligible project, either emergency or permanent work, with a damage dollar value of $52,000 or greater.

Latitude

The location north or south in reference to the equator, which is designated at zero (0) degrees. Parallel lines that circle the globe both north and south of the equator. The poles are at 90 degrees North and South latitude.

Leeward

The side of an object or obstacle, such as a ship’s sail, a mountain or a hill, furthest away from the wind, and therefore, protected from the direct force of the wind. The opposite of windward.

LEOC

Local Emergency Operations Center

LFA

Lead Federal Agency

LFD

Letter of Final Determination

LH

Local Hire

LMMP

Limited Map Maintenance Program

Local Action Statement

A release prepared by a National Weather Service Forecast Office in or near a threatened area giving specific details for its area of responsibility

LODR

Letter of Determination Review

LOG

Logistics

LOMA

Letter of Map Amendment

LOMC

Letter of Map Change

LOMR

Letter of Map Revision

LOMR-F

Letter of Map Revision Based on Fill

Longitude

The location east or west in reference to the Prime Meridian, which is designated as zero (0) degrees longitude. The distance between lines of longitude are greater at the equator and smaller at the higher latitudes, intersecting at the earth’s North and South Poles. Time zones are correlated to longitude.

Low

A region of low pressure

Low-Level Invest

An investigative mission for tropical disturbances to: 1) determine the existence or non-existence of a closed circulation (winds blowing in a complete circle); 2) supply weather observations in required areas; and 3) determine the vortex center, if any. These missions are flown at 500 to 1500 feet.

Low-Pressure System

An area of a relative pressure minimum that has converging winds and rotates in the same direction as the earth. This is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. Also known as a cyclone, it is the opposite of an area of high pressure, or a anticyclone.

M

Statute Mile

M&IE

Miscellaneous and Incidental Expenses

M/S

Meters Per Second

MA

Mission Assignment

MACA

Military Assistance to Civil Authorities

MACDIS

Military Assistance for Civil Disturbances

MACS

Multi-Agency Coordination System

Maximum Envelope of Water (MEOW)

Describes the predicted areas inundated and amount of storm surge for a particular area during the landfall of a hurricane. Used in the SLOSH Model.

Maximum Envelope of Wind (MEOW)

Describes the predicted areas inundated and amount of wind for a particular area during the landfall of a hurricane. Used in the Inland Wind Model.

MB

Millibars

Mean Sea Level

The heights of the sea surface midway between its average high and low water positions.

MEOW

Maximum Envelope of Water or Maximum Envelope of Winds

MERS

Mobile Emergency Response Support

Millibar (MB)

A metric measurement of atmospheric pressure used by the National Weather Service. Standard surface pressure is 1,013.2 millibars.

MMRS

Metropolitan Medical Response System

MOA

Memorandum of Agreement

MOC

MERS Operations Center (FEMA)

MOU

Memorandum of Understanding

MP

Management Profile

MPH

Miles per hour

MSC

Map Service Center

MSCA

Military Support to Civil Authorities

MSCLEA

Military Support to Civilian Law Enforcement Agencies

MSEHPA

Model State Emergency Health Powers Act

MSHA

Mine Safety and Health Administration

MT

Mitigation Directorate

MWEAC

Mount Weather Emergency Assistance Branch

NAHC

National Advisory Health Council

NASA

National Aeronautics and Space Administration

National Centers for Environmental Prediction (NCEP)

As part of the National Weather Service, the centers provide timely, accurate and continually improving worldwide forecast guidance products. Some of the centers include the Aviation Weather Center, the Climate Prediction Center, the Storm Prediction Center and the Tropical Prediction Center. Formerly known as NMC.

National Hurricane Center (NHC)

A branch of the Tropical Prediction Center under the National Weather Service, it is responsible for tracking and forecasting tropical cyclones over the North Atlantic, Caribbean, Gulf of Mexico and the Eastern Pacific.

National Oceanic and Atmospheric Administration (NOAA)

An administration of the U.S. Department of Commerce, it is the parent organization of the National Weather Service. It promotes global environmental stewardship, emphasizing atmospheric and marine resources.

National Weather Service (NWS)

A primary office of the National Oceanic and Atmospheric Administration responsible for all aspects of observing and forecasting atmospheric conditions and their consequences, including severe weather and flood warnings

Nautical Mile

A unit of length used in marine navigation equal to a minute of arc of a great circle on a sphere. One international nautical mile is equivalent to 1,852 meters or 1.151 statue miles. Refer to a sea mile.

NAWAS

National Warning System

NCP

National Oil and Hazardous Substances Pollution Contingency Plan

NDAA

National Defense Authorization Act

NDMS

National Disaster Medical System

NDPO

FBI’s National Domestic Preparedness Office

NDSITC

National Dam Safety Information Technology Committee

NECC

National Emergency Coordination Center (FEMA)

NEHRP

National Earthquake Hazards Reduction Program

NEMA

National Emergency Management Agency

NEMIS

National Emergency Management Information System

NEOC

National Emergency Operations Center

NEPA

National Environmental Policy Act

NEST

Nuclear Emergency Support Team

NETC

National Emergency Training Center

NEXRAD (Next Generation Weather Radar)

A network of advanced Doppler radars implemented in the United States between 1992 and 1996 which detects the location and intensity of precipitation extending to a range of 143 miles from the radar site. NEXRAD Doppler radar is highly sensitive and can detect precipitation from very light rain and snow up to the strongest thunderstorms with accuracy and detail. Sometimes, however, the radar’s extreme sensitivity will cause ground clutter and other non-precipitation echoes to be displayed in the vicinity of the radar site.

NFA

National Fire Academy

NFIC

National Fire Information Council

NFIF

National Flood Insurance Fund

NFIP

National Flood Insurance Program

NFIRA

National Flood Insurance Reform Act

NFIRS

National Fire Incident Reporting System

NGB

National Guard Bureau

NHC

National Hurricane Center

NHPA

National Historic Preservation Act

NID

National Inventory of Dams

NIH

National Institute of Health

NIMA

National Imagery and Mapping Agency

NIPC

National Infrastructure Protection Center

NIRT

Nuclear Incident Response Team

NM

Nautical mile

NMFS

National Marine Fisheries Service

NMRT

National Medical Response Team

NNOB

National Network Operations Branch

NNOC

National Network Operations Center

NOAA

National Oceanic and Atmospheric Service

NOAA Weather Radio

A 24-hour continuous broadcast of existing and forecasted weather conditions, operated and broadcast by the local field offices of the National Weather Service

NOC

Negotiations Operations Center

NOI

Notice of Interest

NORAD

North America Aerospace Defense Command

North Atlantic Basin (sometimes called the Atlantic Basin)

The Atlantic Ocean north of the equator, the Caribbean Sea and the Gulf of Mexico

Notification

To inform appropriate individuals about an emergency condition so they can take appropriate action

NPDP

National Performance of Dams Program

NPS

National Park Service

NPSC

National Process Serving Center (FEMA)

NRC

Nuclear Regulatory Commission

NRCS

National Resources Conservation Service

NRO

National Reconnaissance Organization

NRP

National Response Plan

NS

FEMA’s Office of National Security Affairs

NSA

National Security Agency

NSC

National Security Council

NSTAC

National Security Telecommunications Advisory Committee

NTC

National Teleregistration Center (FEMA)

NTSP

National Plan for Telecommunications Support in Non-Wartime Emergencies

NVOAD

National Voluntary Organizations Active in Disaster

NWS

National Weather Service

NWSFO

National Weather Service Forecasting Office

Occluded Front

The front formed by a cold front overtaking a warm or stationary front and lifting the warm air above the earth’s surface

OEP

Office of Emergency Preparedness

OFA

Other federal agencies

OFM

FEMA’s Office of Financial Management

OMB

Office of Management and Budget

OP

FEMA’s Office of Policy and Regional Operations

OPA

Otherwise protected areas

OS

FEMA’s Operations Support Directorate

OSC

On-Scene Commander (FBI), On-Scene Coordinator (EPA)

OSHA

Occupational Safety and Health Administration

OSM

Office of Surface Mining

OSTP

Office of Science and Technology Policy

PA

Public Assistance

P Affairs O

Public Affairs Officer

P Assist O

Public Assistance Officer

PA

Public Affairs

PBX

Private Branch Exchange

PC-TARE

Personal Computer-Time and Attendance Report

PDA

Preliminary Damage Assessment

PDD-39

Presidential Decision Directive 39

Permanent Work

Work that must be performed through repairs or replacement to restore an eligible facility on the basis of its pre-disaster design, use and current applicable standards

PFOR

Principal Federal Official Representative

PFT

Permanent full time

PHSA

Public Health Service Act

PIO

Public Information Officer

PMR

Physical map revision

PO

Purchase Officer

Polar-Orbiting Satellite

A satellite whose orbit passes over both of the earth’s poles. Compare with a geostationary satellite.

Post-Storm Report

A report issued by a local National Weather Service office summarizing the impact of a tropical cyclone on its forecast area. These reports include information on observed winds, pressures, storm surges, rainfall, tornadoes, damage and casualties.

PPA

Plant Protection Act

PPC

Prevention Preparedness Council

Pre-Eye Landfall Time

The time before actual hurricane eye landfall within which evacuation cannot be carried out because of earlier effects, such as the inundation of evacuation routes from the storm surge or rainfall and the arrival of sustained gale force winds. It is composed of the time of arrival of sustained gale-force winds or the time roadway inundation from storm surge/rainfall begins, whichever comes first.

Preliminary Damage Assessment (PDA)

A survey to determine the impact and magnitude of damage caused by the disaster and the resulting unmet needs of the public sector and community at large. The PDA is the basis for estimating total disaster-related damage and evaluating the need to request a Presidential declaration of disaster.

Preliminary Report

A report summarizing the life history and effects of an Atlantic or eastern Pacific tropical cyclone. It contains a summary of the cyclone life cycle and pertinent meteorological data, including the post-analysis best track (six-hourly positions and intensities) and other meteorological statistics. It also contains a description of damage and casualties the system produced, as well as information on forecasts and warnings associated with the cyclone. NHC writes a preliminary report on every tropical cyclone in its area of responsibility.

Present Movement

The best estimate of the movement of the center of a tropical cyclone at a given time and given position. This estimate does not reflect the short-period, small scale oscillations of the cyclone center.

Pressure

The force per unit area exerted by the weight of the atmosphere above a point on or above the earth’s surface. Also known as atmospheric pressure or barometric pressure.

Private Nonprofit Organization (PNP)

Any non-governmental agency or entity that currently has either an effective ruling letter from the U.S. Internal Revenue Service granting tax exemption, or satisfactory evidence from the state that the non-revenue producing organization or entity is a nonprofit one organized or operating under state law.

Pro A

Programmatic Agreement

Back to top

Probability of Tropical Cyclone Conditions

The probability, in percent, that the cyclone center will pass within 50 miles to the right or 75 miles to the left of the listed location within the indicated time period when looking at the coast in the direction of the cyclone’s movement.

Project

A logical method of performing work required as a result of the declared event

Project Formulation

A technique for determining small projects by consolidating like work items into one project, to expedite approval and funding and to facilitate project management

Project Officer (PO)

An emergency management employee with demonstrated experience and training in management of large and complex repair projects

Project Worksheet (PW)

A form used to document the damage and develop the scope of work for repair of a damage site

PRP

Preferred Risk Policy

PT

FEMA’s Preparedness, Training and Exercises Directorate

PTE

Preparedness, Training and Exercises

Public Assistance (PA)

Supplementary federal assistance provided under the Stafford Act to state and local governments or certain private, nonprofit organizations, other than assistance for the direct benefit of individuals and families

Public Assistance Coordinator (PAC)

An emergency management employee who is responsible for providing continuity of service to an applicant in the Public Assistance program

Public Information Officer

A person appointed by a County Emergency Operations Center to be responsible for the formulating and coordinating of the dissemination of emergency public information with both the electronic and written media, ensuring that accurate information is being released to the general public

PUP

Principle User Processor

R&R

Resource and Recovery

RACES

Radio Amateur Civil Emergency Service

RADAR (Radio Detection and Ranging)

An electronic instrument using ultra high-frequency radio waves to detect distant objects and measure their range by how they scatter or reflect radio energy. Precipitation and clouds are detected by measuring the strength of the electromagnetic signal reflected back. Doppler radar and NEXRAD are examples.

RADCON

Radiological Control Team

Rain

Precipitation in the form of liquid water droplets greater than 0.5 mm. If widely scattered, the drop size may be smaller. It is reported as r in an observation. The intensity of rain is based on rate of fall: very light (r–) means that the scattered drops do not completely wet a surface; light (r-) means it is greater than a trace and up to 0.10 inch an hour; moderate (r) means the rate of fall is between 0.11 to 0.30 inch per hour; heavy (r+) means over 0.30 inch per hour.

Rapid Deepening

A decrease in the minimum sea-level pressure of a tropical cyclone of 1.75 mb/hr or 42 mb for 24 hours

RCBAP

Residential Condominium Building Association Policy

RCRA

Resource Conservation and Recovery Act

RD

Regional Director

REACT

Radio Emergency Associated Communication Team

REC

Regional Emergency Coordinator

Reconnaissance (RECCO) Code

An aircraft weather reconnaissance code that has come to refer primarily to in-flight tropical weather observations, but actually signifies any detailed weather observation or investigation from an aircraft in flight

Relocated

A term used in an advisory to indicate that a vector drawn from the preceding advisory position to the latest know position is not necessarily a reasonable representation of the cyclone’s movement

REO

Regional Environmental Officer

REOC

Regional Emergency Operations Center

REP

Radiological Emergency Preparedness

Results Act

Government Performance and Results Act

Request for Public Assistance (Request)

The official notification of intent to apply for public assistance monies following declaration of a disaster. It is a short form that asks for general identifying information about an applicant.

ROC

Regional Operations Center

RR

Response and Recovery; also FEMA’s Response and Recovery Directorate

RRIS

Rapid Response Information System

RRT

Regional Response Team

RTF

Response Task Forces

RWA

Reimbursable Work Authorization

S&E

Salaries and Expenses

SAC

Special Agent-in-Charge

Saffir-Simpson Damage-Potential Scale

A scale from 1 to 5, developed in the early 1970s by Herbert Saffir, a consulting engineer, and Robert Simpson, then Director of the National Hurricane Center, to measure the intensity of a hurricane. The scale categorizes potential damage based on barometric pressure, wind speeds and storm surge. Scale numbers are available to public safety officials when a hurricane is within 72 hours of landfall. Scale assessments are revised regularly as new observations are made. Public safety organizations are kept informed of new estimates of the hurricane’s disaster potential.

SARA

Superfund Amendments & Reauthorization Act

SARS

Severe Acute Respiratory Syndrome

Satellite

Used in reference to the manufactured objects that orbit the earth, either in a geostationary or a polar manner. Some of the information that is gathered by weather satellites, such as GOES9, includes upper air temperatures and humidity, recording the temperatures of cloud tops, land and ocean, monitoring the movement of clouds to determine upper level wind speeds, tracing the movement of water vapor, monitoring the sun and solar activity, and relaying data from weather instruments around the world.

Satellite Pictures

Pictures taken by a weather satellite, such as GOES-9, that reveal information, such as the flow of water vapor, the movement of frontal systems and the development of a tropical system. Looping individual pictures aids meteorologists in forecasting. Pictures can be taken is as a visible shot, which is best during times of visible light (daylight) or as an IR (infrared) shot, which reveals cloud temperatures and can be taken day or night.

SBA

Small Business Administration

SBCCOM

Soldier & Biological Chemical Command (U.S. Army)

SCO

State Coordinating Officer

SDF

Special Direct Facility

SEED

Safety Evaluation of Existing Dams

SEOC

State Emergency Operations Center

Severe Thunderstorm Warning

Issued to indicate that severe thunderstorms have been sighted or indicated on radar

Severe Thunderstorm Watch

Issued to indicate that conditions are favorable for lightning, damaging winds greater than 58 miles an hour, and hail and/or heavy rainfall.

SFHA

Special Flood Hazard Area

SFHDF

Standard Flood Hazard Determination Form

SFIP

Standard Flood Insurance Policy

SFO

Senior FEMA Official

Shelter Period

The period in which people are forced to evacuate their homes. This time may vary from several hours to a couple of days, depending upon the severity of the hurricane.

SHPO

State Historic Preservation Office

Shutters

A physical wind barrier that is affixed over the outside of windows and/or doors to protect these vulnerable areas during a tropical storm. These products are classified by the styles of panel (accordion or rolling) and are manufactured from steel, aluminum, plastic or plywood.

SIES

Strategic Industries and Economic Security

SIOC

Strategic Information and Operations Center

SITREP

Situation Report

SLOSH

Sea, Lake and Overland Surges for Hurricanes. A computerized model that is able to estimate the overland tidal surge heights and winds that result from hypothetical hurricanes with selected characteristics in pressure, size, forward speed, track and winds. The resultant tidal surge is then applied to a specific locale’s shoreline, incorporating the unique bay and river configurations, water depths, bridges, roads and other physical features. The model estimates open coastline heights as well as surge heights over land, thus predicting the degree of propagation or run-up of the surge into inland areas.

Small Craft Advisory

An advisory issued for marine interests, especially for operators of small boats or other vessels. Conditions include wind speeds between 20 knots (23 mph) and 34 knots (39 mph). Issued up to 12 hours ahead of conditions.

Small Project

An eligible project, either emergency or permanent work, with a damage dollar value of less than $52,000

SMMA

Standard Mitigation Measures Agreement

SMSD

State Management of Small Disasters

SOP

Standard Operating Procedures

Special Considerations

Factors that must be addressed before federal grant money can be obligated to repair or restore damaged facilities. These factors include, but are not limited to, general and flood insurance, historic preservation, environmental protection and hazard mitigation.

Special Marine Warning

A warning for hazardous weather conditions, usually short and not adequately covered by existing marine warnings. Such conditions include sustained winds or gusts of 35 knots or more for 2 hours or less.

Specialist

An emergency management employee with demonstrated technical expertise in a defined specialty

Spiral Rainbands

Bands of thunderstorms that spiral inward towards the center, where they wrap themselves around the eye

Squall

A sudden increase of wind speed by at least 18 miles per hour (16 knots) and rising to 25 miles per hour (22 knots) or more and lasting for at least one minute

Stafford Act

Robert T. Stafford Disaster Relief and Emergency Assistance Act, Public Law 93-288, as amended

Standard Surface Pressure

The measurement of one atmosphere of pressure under standard conditions. It is equivalent to 1,013.25 millibars, 29.92 inches of mercury, 760 millimeters of mercury, 14.7 pounds per square inch, or 1.033 grams per square centimeter.

State of Emergency

A declaration made by the Chief Elected Official of a state, county or city government which entails a heightened level of activation and mobilization of staff to protect property and lives

STATEX

Statutory Exclusion

Stationary Front

The boundary between two air masses, neither of which is replacing the other

Statute Mile

Commonly known as a ground mile

STOC

Sniper Tactical Operations Center

Storm

An individual low-pressure disturbance, complete with winds, clouds and precipitation. Examples include thunderstorms, tornadoes or even tropical cyclones. The name is associated with destructive or unpleasant weather.

Storm Surge

An abnormal rise in sea level accompanying a hurricane or other intense storm, and whose height is the difference between the observed level of the sea surface and the level that would have occurred in the absence of the cyclone. Storm surge is usually estimated by subtracting the normal or astronomic high tide from the observed storm tide. Note that waves on top of the storm surge will create an even greater high-water mark.

Storm Tide

The actual level of seawater resulting from the astronomic tide combined with the storm surge. If the storm comes ashore during astronomical low tide, the surge will be decreased by the amount of the low tide. If the storm makes landfall during astronomical high tide, the surge will be that much higher.

Storm Tracks

The path or tracks generally followed by a cyclonic disturbance

Subtropical

The region between the tropical and temperate regions, an area between 35 and 40 degrees North and South latitude. This is generally an area of semi-permanent high pressure, and is where the Azores and North Pacific Highs may be found.

Subtropical Cyclone

A low pressure system that develops over subtropical waters that initially has a non-tropical circulation but in which some elements of tropical cyclone cloud structure are present. Subtropical cyclones can evolve into tropical cyclones.

Subtropical Depression

A subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 38 mph (33 knots) or less

Subtropical High

A semi-permanent high-pressure region near 30 degrees latitude

Subtropical Storm

A subtropical cyclone in which the maximum sustained surface wind speed (using the U.S. 1-minute average) is 39 mph (34 knots) or more

Swath

The width of the path of the hurricane. Usually this path area is about 125 miles wide with 75 miles to the right of the eye and 50 miles to the left of the eye.

SWM

Department of Solid Waste Management

Synoptic Scale

The size of migratory high and low pressure systems, such as hurricanes, in the lower troposphere that cover a horizontal area of several hundred miles or more. Contrasts with macroscale, mesoscale and storms.

Synoptic Surveillance Track

Weather reconnaissance mission flown to provide vital meteorological information in data-sparse ocean areas as a supplement to existing surface, radar and satellite data. Synoptic flights better define the upper atmosphere and aid in the prediction of tropical cyclone development and movement.

T&E

Threatened and Endangered

TAC

Technical Assistance Contractor

TADS

Training Aids for Dam Safety

TAFB

Tropical Analysis and Forecast Branch (TPC)

Tailwater

The water immediately downstream from a dam. The water surface elevation varies due to fluctuations in the outflow from the structures of a dam. Tailwater monitoring is an important consideration because a failure of a dam will cause a rapid rise in the level of the tailwater.

TCIM

Threat Countermeasures and Incident Management Directorate

TD

Tropical Depression

TDY

Temporary duty

TEC

Technical Evaluation Contractor

TEU

Technical Escort Unit

TH

Temporary housing

THO

Temporary Housing Officer

THPO

Tribal Historic Preservation Officer (refers to activities on native American tribal lands)

Thunder

The sound that follows a flash of lightning and is caused by sudden expansion of the air in the path of the electrical discharge

Thunderstorm

A local storm produced by a cumulonimbus cloud, always with lightning and thunder, and usually accompanied by strong gusts of wind, heavy rain and sometimes hail

TLC

Territorial Logistics Center

TOC

Tactical Operations Center

Tornado

A violently rotating column of air in contact with and extending between a convective cloud and the surface of the earth. It is the most destructive of all storm-scale atmospheric phenomena. They can occur anywhere in the world given the right conditions, especially after the landfall of hurricanes.

TPC

Tropical Prediction Center

Trade Winds

The wind system, occupying most of the tropics, which are northeasterly in the Northern Hemisphere and southeasterly in the Southern Hemisphere.

TRIPS

Travel, Reporting and Information Processing System

Tropical Cyclone

A general term for all cyclone circulations originating over tropical waters. Its characteristics include a warm-core, non-frontal pressure system of synoptic scale that originates over the tropical or subtropical waters and has a definite organized surface. Used to define wind circulations rotating around an atmosphere which includes tropical depressions, tropical storms and hurricanes. The strongest winds of this cyclone are typically near the Earth’s surface.

Tropical Cyclone Plan of the Day

A coordinated mission plan that tasks operational weather reconnaissance requirements as required. Describes reconnaissance flights committed to satisfy both operational and research requirements, and identifies possible reconnaissance requirements for the succeeding 24-hour period.

Tropical Depression (TD)

A tropical cyclone in which the maximum sustained surface winds (1 minute average) are 38 miles per hour (33 knots) or less. Characteristically having one or more closed isobars, it may form slowly from a tropical disturbance or an easterly wave which has continued to organize. At this point, it gets a cyclone number, starting with TD01 at the beginning of each storm season.

Tropical Disturbance

A discrete system of clouds, showers and thunderstorms (organized convection) that originate in the tropics. Generally 100 to 300 miles in diameter and originating in the tropics or subtropics, disturbances have a non-frontal migratory character, and maintain their identity for 24 hours or more. It may or may not be associated with a detectable perturbation of the wind field. An upper level of low pressure causes this to occur. Approximately 100 of these types of events occur annually during hurricane season.

Tropical Prediction Center

A division of the National Centers for Environmental Prediction, the Center issues watches, warnings, forecasts and analyses of hazardous weather conditions in the tropics for both domestic and international communities which include the Atlantic, Caribbean, Gulf of Mexico and Eastern Pacific. The National Hurricane Center is one of its branches.

Tropical Storm (TS)

A tropical cyclone in which the maximum sustained surface wind speed (1 minute average) is within the range of 39 to 73 mph (34 to 63 knots). At this point, the system is given a name to identify and track it. In the Atlantic/Caribbean/Gulf of Mexico basin, the names start with A each season.

Tropical Storm Warning

A warning issued by the National Hurricane Center for tropical storm conditions including possible sustained winds within the range 39 to 73 mph (34 to 63 knots) which are expected in a specified coastal area within 24 hours or less.

Tropical Storm Watch

An announcement issued by the National Hurricane Center for specific areas that a tropical storm or a forecast of tropical storm conditions poses a possible threat to coastal areas generally within 36 hours. A tropical storm watch normally should not be issued if the system is forecast to attain hurricane strength.

Tropical Wave

Another name for an easterly wave, it is an area of relatively low pressure (trough) moving westward through the trade wind easterlies. Generally, it is associated with extensive cloudiness and showers, and may be associated with possible tropical cyclone development.

Tropics/Tropical

The region of the earth located between the Tropic of Cancer, at 23.5 degrees North latitude, and the Tropic of Capricorn, at 23.5 degrees South latitude. It encompasses the equatorial region, an area of high temperatures and considerable precipitation during part of the year.

TS

Tropical storm

TSB

Technical Support Branch (TPC).

TVA

Tennessee Valley Authority

Typhoon

A hurricane that occurs in the Pacific Region of the Philippines or the China Sea

UASI

Urban Areas Security Initiative, provides direct funding for high threat areas

UC

Unified Command

Universal Time Coordinate (UTC)

One of several names for the twenty-four hour time that is used throughout the scientific and military communities. Other names for this time measurement are Greenwich Mean Time (GMT) or Zulu Time (Z). See Greenwich Mean Time for more information.

Upwelling

The process by which water rises from a lower to a higher depth, usually as a result of divergence and offshore currents. It influences climate by bringing colder, more nutrient-rich water to the surface. This is a vital factor of the El Nino event.

US&R

Urban Search & Rescue

USACE

U.S. Army Corps of Engineers

USAF

U.S. Air Force

USBR

U.S. Bureau of Reclamation

USCA

United States Code Annotated

USCG

U.S. Coast Guard

Back to top

USDA

U.S. Food and Drug Administration

USFA

United States Fire Administration

USFS

United States Forest Service

USFWS

U.S. Fish and Wildlife Service

USG CONPLAN

United States Government Interagency Domestic Terrorism Concept of Operations Plan

USGS

U.S. Geological Survey

USN

U.S. Navy

USSD

United States Society on Dams

UTC

Universal Time Coordinate

Validation

The pre-funding verification that proposed or completed work projects meet statutory and regulatory compliance

VOLAG

Voluntary Agent

Vortex

Any circular or rotary flow in the atmosphere that possesses vorticity

Vortex Fix

The location of the surface and/or flight level center of a tropical or subtropical cyclone obtained by reconnaissance aircraft penetration

Vorticity

The measurement of the rotation of a small air parcel. It has vorticity when the parcel spins as it moves along its path. Although the axis of the rotation can extend in any direction, meteorologists are primarily concerned with the rotational motion about an axis that is perpendicular to the earth’s surface. If it does not spin, it is said to have zero vorticity. In the Northern Hemisphere, the vorticity is positive when the parcel has a counterclockwise, or cyclonic, rotation. It is negative when the parcel has clockwise, or anticyclonic, rotation.

Warm Front

The leading edge of an advancing warm air mass that is replacing a retreating relatively colder air mass. Generally, with the passage of a warm front, the temperature and humidity increase, the pressure rises, and although the wind shifts (usually from the southwest to the northwest in the Northern Hemisphere), it is not as pronounced as with a cold frontal passage. Precipitation, in the form of rain, snow or drizzle, is generally found ahead of the surface front, as well as convective showers and thunderstorms. Fog is common in the cold air ahead of the front. Although clearing usually occurs after passage, some conditions may produced fog in the warm air. See occluded front and cold front.

Warning

An announcement that is issued when severe weather: 1) has developed; 2) is already occurring and reported; or 3) is detected on radar. Warnings state a particular hazard or imminent danger, such as tornadoes, severe thunderstorms, flash and river floods, hurricanes, etc.

Weather Surveillance Radar (WSR-88D)

The newest generation of Doppler radars. These radar units, with help from a set of computers, show very detailed images of precipitation and other phenomena, including air motions within a storm.

WFO

Weather Forecast Office

Windward

The direction from which the wind is blowing. Also known as the upwind side of an object. It is the opposite of the downwind or leeward side.

WMD

Weapon of Mass Destruction

WMD-CST

Weapons of Mass Destruction Civil Support Team

WWW

World Wide Web

WYO

Write Your Own

Z

Zulu Time

Zulu Time (Z)

One of several names for the twenty-four hour time that is used throughout the scientific and military communities. Other names for this time measurement are Universal Time Coordinate (UTC) or Greenwich Mean Time (GMT). See Greenwich Mean Time for more information.