Hummocked IceIce piled haphazardly one piece over another to form an uneven surface.
Hurricane(abbrev. HURCN) A tropical cyclone in the Atlantic, Caribbean Sea, Gulf of Mexico, or eastern Pacific, which the maximum 1-minute sustained surface wind…
Hurricane / TyphoonA tropical cyclone in which the maximum sustained surface wind (using the U.S. 1-minute average) is 64 kt (74 mph or 119 km/hr) or more.
Hurricane Force Wind WarningA warning for sustained winds, or frequent gusts, of 64 knots (74 mph) or greater, either predicted or occurring, and not directly associated with a…
Hurricane Local StatementA public release prepared by local National Weather Service offices in or near a threatened area giving specific details for its county/parish warning…
Hurricane SeasonThe part of the year having a relatively high incidence of tropical cyclones. In the Atlantic, Caribbean, and Gulf of Mexico, and central North Pacific…
Hurricane WarningA warning that sustained winds 64 kt (74 mph or 119 kph) or higher associated with a hurricane are expected in a specified coastal area in 24 hours or…
Hurricane WatchAn announcement of specific coastal areas that a hurricane or an incipient hurricane condition poses a possible threat, generally within 36 hours
Hyder FlareIn solar-terrestrial terms, a filiment-associated two-ribbon flare, often occurring in spotless regions.
Hydraulic Fill DamAn embankment dam constructed of materials, often dredged, which are conveyed and/or placed by suspension in flowing water.
Hydraulic FlowAtmospheric flow that is similar in character to the flow of water over an obstacle.
Hydraulic Grade LineA line whose plotted ordinate position represents the sum of pressure head plus elevation head for the various positions along a given fluid flow path…
Hydraulic Head(1) The height of the free surface of a body of water above a given point beneath the surface.
Hydraulic JumpA steady disturbance in the lee of a mountain, where the airflow passing over the mountain suddenly changes from a region of low depth and high velocity…
Hydraulic PermeabilityThe flow of water through a unit cross-sectional area of soil normal to the direction of flow when the hydraulic gradient is unity.
HydrocarbonsSubstances containing only hydrogen and carbon. Fossil fuels are made up of hydrocarbons.
Hydrochlorofluorocarbons (HCFCs)Compounds containing hydrogen, fluorine, chlorine, and carbon atoms. Although ozone depleting substances, they are less potent at destroying stratospheric…
Hydroelectric Power PlantA power plant that produces electricity by the force of water falling through a hydro turbine that spins a generator.
Hydrofluorocarbons (HFCs)Compounds containing only hydrogen, fluorine, and carbon atoms. They were introduced as alternatives to ozone depleting substances in serving many…
HydrographA graphical representation of the stage or discharge as a function of time at a particular point on a watercourse; a time-discharge curve of the unsteady…
Hydrograph SeparationThe process where the storm hydrograph is separated into baseflow components and surface runoff components.
Hydrographic SurveyAn instrumental survey to measure and determine characteristics of streams and other bodies of water within an area, including such things as location…
Hydrologic BudgetAn accounting of the inflow to, outflow from, and storage in, a hydrologic unit, such as a drainage basin, aquifer, soil zone, lake, reservoir, or…
Hydrologic CycleCycle of water movement from atmosphere to Earth by precipitation and its return to the atmosphere by interception, evaporation, runoff, infiltration…
Hydrologic EquationThe water inventory equation (Inflow = Outflow + Change in Storage) which expresses the basic principle that during a given time interval the total inflow…
Hydrologic ModelA conceptual or physically-based procedure for numerically simulating a process or processes which occur in a watershed.
Hydrologic Service AreaHSA. A geographical area assigned to Weather Service Forecast Office's/Weather Forecast Office's that embraces one or more rivers.
HydrologyThe science dealing with the distribution, properties and circulation of water on land, in the soil, and in the atmosphere.
HydrometeorA particle of condensed water (liquid, snow, ice, graupel, hail) in the atmosphere.
hydrometeor typesInformation that delineates hydrometeors into such microphysical classes as rain, snow, graupel, and hail.
HydrometeorologistsIn hydrologic terms, individuals who have the combined knowledge in the fields of both meteorology and hydrology which enables them to study and solve…
HydrometeorologyAn interÂdisciÂplinary science involving the study and analysis of the interÂrelationÂships between the atmoÂspheric and land phases of…
HydropowerThe force of flowing water moving downstream creates energy that can be harnessed and turned into electricity.
HydrosphereThe region that includes all the earth's liquid water, frozen water, floating ice, frozen upper layer of soil, and the small amounts of water vapor in the…
Hydrostatic HeadA measure of pressure at a given point in a liquid in terms of the vertical height of a column of the same liquid which would produce the same pressure.
HydroÂmeteorologyAn interÂdisciÂplinary science involving the study and analysis of the interÂrelationÂships between the atmoÂspheric and land phases of…
HyetographA graphical representation of rainfall intensity with respect to time.
HygrometerAn instrument which measures the humidity of the air.
HygroscopicAbsorbing or attracting moisture from the air.
hygroscopic growthThe rate that aerosol particles grow at relative humidity values less than 100 percent.
Hypothermiathis situation occurs when the core temperature of one's body falls below normal.
HypothesisA tentative proposal made to explain certain observations or facts that requires further investigation to be verified.