Active crowning: Industry term referring to a crown fire (see below) involving an entire stand of trees.
Adjacent areas: Product-specific term for areas of high structure density in closest proximity to natural fuel beds.
Crown fire: Industry term referring to the movement of surface fire into the tree canopy via ladder fuels (see below).
Ember cast: Industry term for the production of firebrands from burning vegetation that are carried aloft for some distance, then deposited on the surface ahead of the fire front.
Fireline intensity: Industry term; "the product of the available heat of combustion per unit of ground and the rate of spread of the fire, interpreted as heat release per unit of time for each length of the fire edge [Glossary of Wildland Fire, National Wildfire Coordinating Group]."
Fire perimeter: Product-specific term for an area that has recently suffered a wildfire and, as a result of that fire, has reduced fuel or no fuel.
Fireshed: In general usage, a fireshed is a boundary between areas where a fire would behave in different ways or move in different directions. In Wildfire Risk, fireshed refers to areas that have the same fire behavior.
Fuel islands: Product-specific term used to denote areas of fuel that are surrounded by dense development.
Interface: Industry term for areas with high structure density, where structures and roads are the defining characteristics of the landscape.
Intermix: Product-specific term for areas characterized by a higher density of structures than wildland areas (see below), but less than the structure density of interface areas (see above). Roads and other infrastructure break up fuel continuity in intermix areas.
Ladder fuels: Industry term referring to the lowest branches of the dominant vegetation type in a given area.
Peripheral areas: Product-specific term for areas with a high structure density, but at a greater distance from natural fuel beds than adjacent areas (see above).
Pixel: Product-specific term for a 30-meter by 30-meter square portion of topography.
Probability of ignition: Product-specific term for how likely an ember is to catch in fine vegetation and start a fire, based on climate (temperature and humidity), vegetation cover, aspect, and elevation.
Torching: Industry term for crown fire (see above) involving a single tree.
Urban conflagration: Urban conflagration is defined as a "large, destructive fire that spreads beyond natural or artificial barriers; it can be expected to result in large monetary loss and may or may not include fatalities." An urban conflagration moves beyond a block and destroys whole sections of a city.
Wildland: Product-specific terms referring to areas with relatively continuous fuel and limited presence of structures, roads, and other human-caused disturbances.
Wind aligned roads: Product-specific term referring to roads that are aligned with the predominant wind direction in a given area.