Hazard Reduction – Treatment of living or dead forest fuels to diminish the likelihood of a fire starting, and to lessen the potential rate of spread and resistance to control. Synonym - Fuel Treatment.

Heat Transfer – The process by which heat is imparted from one body or object to another. In forest fires, heat energy is transmitted from burning to unburned fuels by:

• Convection – Transfer of heat by the movement of masses of hot air; the natural direction is upwards in the absence of any appreciable wind speed and/or slope.
• Radiation – Transfer of heat in straight lines from warm surfaces to cooler surroundings.
• Conduction – Transfer of heat through solid matter.

  Note: In forest fires, the transmission of heat may also take place by solid mass or ember transport. This is the transfer of heat resulting from firebrands being transported ahead of a fire by the wind, by gravity (e.g. rolling downhill), or being carried aloft in the convection column or by a fire whirl (i.e. spotting).

Held Line – All control line that still contains the fire when it is declare under control.

Helibucket – A specially designed rigid or collapsible container slung by a helicopter and used for picking up and dropping suppressants or retardants on a fire. Size of bucket load is compatible with the size of helicopter.

Helicopter Sounding – Determination of the vertical temperature profile based on observations of a helicopter's free-air thermometer and corresponding altimeter readings.

Helipad – The prepared surface or structure at a heliport where a helicopter actually lands.

Heliport – A permanent landing area for helicopters, where fuel, service, and supply are generally available.

Helispot – A temporary area prepared to facilitate helicopter landings.

Helitack – Initial attack on wildfires involving the use of helicopters and trained crews, deployed as a complete unit.

Helitack Crew – An initial attack crew specially trained in the tactical and logistical use of helicopters for fire suppression.

Helitanker – A helicopter equipped with a helitank or a bucket. Note Airtanker

Helitorch – A specialized aerial drip torch, primarily using a gelled fuel, slung and activated from a helicopter.

Hose – Conveys water under positive and sometimes negative pressure from the fire pumping unit to the outlet normally affixed with standardized couplings or connectors.

Suction Hose – A hose, reinforced to prevent collapse due to pressure, used to draft water into a fire pump.

Hose-lay – The arrangement of connected lengths of fire hose and accessories on the ground beginning at the first pumping unit and ending at the point(s) of water delivery.

Hose Strangler – A crimping device for stopping the flow of water in a hose.

Hot Spot –

• (1) A particularly active part of a fire. Note Hot Spotting under Fire Suppression.
• (2) A small area of smouldering or glowing combustion, which may be exhibiting smoke, located on or within the fire perimeter; a term commonly used during the mop-up stage of a fire. Synonym - Smudge. Note Cold Trailing under Fire Suppression.