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NWCG Glossary of Wildland Fire (PMS 205)

Term Steward Status Definition
humidity IWSC Incident Weather Subcommittee Approved General term referring to the moisture content of the atmosphere.
humus FMSC Fuels Management Subcommittee Approved Layer of decomposed organic matter on the forest floor beneath the fermentation layer and directly above the soil. It is that part of the duff in which decomposition has rendered vegetation unrecognizable and mixing of soil and organic matter is underway.
hydrophobicity IWSC Incident Weather Subcommittee Approved Resistance to wetting exhibited by some soils, also called water repellency. The phenomenon may occur naturally or may be fire-induced. It may be determined by water drop penetration time, equilibrium liquid-contact angles, solid-air surface tension indices, or the characterization of dynamic wetting angles during infiltration. 
hygrothermograph IWSC Incident Weather Subcommittee Approved Recording instrument combining, on one paper record, the variation of dry-bulb temperature and relative humidity as a function of time.
hypalon MFES Mobile Fire Equipment Subcommittee Approved A synthetic rubber with excellent ozone, weathering, and acid resistance. Widely used in fire hose to retard abrasion.
hysteresis MFES Mobile Fire Equipment Subcommittee Approved The under reading of an instrument (such as a pressure gauge) with increasing values (pressure is going up) and the over reading with decreasing values (pressure is going down).
I-Zone WMSC WUI Mitigation Subcommittee Archived An area that, in relation to wildland/urban fire, has a set of conditions that provides the opportunity for fire to burn from wildland vegetation to the home/structure ignition zone.
ICS 209 remarks wfnwcgorg:NISC Approved Additional information pertinent to the management of the incident.
ICS 209 report date time wfnwcgorg:NISC Approved Automated date and time stamp applied when the ICS 209 report is submitted.
ICS 209 report for time period from wfnwcgorg:NISC Approved The beginning date and time of the reporting period of an ICS 209.
ICS 209 report for time period to IMC Integration Management Committee, DCSC Dispatch Coordination Subcommittee Approved The ending date and time of the reporting period of an ICS 209.
ICS 209 report status IMC Integration Management Committee Approved The version of the ICS 209 report (Initial, Update, or Final).
identification run AMC Aviation Management Committee Approved Dry run over the target area by the leadplane to indicate an airtanker's flight path and target, while the airtanker pilot is observing.
igniter FISC Fire Investigation Subcommittee Approved A pyrotechnic device specifically designed to initiate burning of a fuel mixture or propellant.
Ignition Area (IA) FISC Fire Investigation Subcommittee Approved The smallest area that a wildland fire investigator can define based on the physical evidence of the fire pattern indicators, within the specific origin area, in which a competent ignition source came into contact with the first fuel ignited and combustion was sustained.
ignition component FDSC Fire Danger Subcommittee Approved A rating of the probability that a firebrand will cause an actionable fire.
ignition energy IWSC Incident Weather Subcommittee Approved Quantity of heat or electrical energy that must be absorbed by a substance to ignite and burn.
ignition factor FISC Fire Investigation Subcommittee Approved The individual factors which make up the ignition sequence; competent ignition source; the type and form of first fuel ignited; oxidant, plus the circumstances, actions, or natural events that allowed the factors to come together.
ignition method FMSC Fuels Management Subcommittee Approved The means by which a fire is ignited, such as hand-held drip torch, helitorch, and backpack propane tanks.
ignition pattern FMSC Fuels Management Subcommittee Approved Manner in which a prescribed fire is ignited. The distance between ignition lines or points and the sequence of igniting them is determined by weather, fuel, topography, firing technique, and other factors which influence fire behavior and fire effects.
ignition probability FASC Fire Analysis Subcommittee Approved Chance that a firebrand will cause an ignition when it lands on receptive fuels.
ignition sequence FISC Fire Investigation Subcommittee Approved The sequence or order of events that bring a competent ignition source, fuel first ignited and oxidant together allowing them to react with each other.
ignition source PIC Public Information Management Committee, EPSC Education & Prevention Subcommittee Approved Any process or event capable of causing a fire.
ignition time FASC Fire Analysis Subcommittee Approved Time between application of an ignition source and self-sustained combustion of a fuel.
ignition trigger IWSC Incident Weather Subcommittee Approved A causative agent for wildland fire. For example, human or lightning.
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