Glossary of Wildfire Terms

Watch out situations: A list of 18 situations for firefighters to be aware of, which signal potential hazards on the fire line; originated from analysis of generations of similar incidents.
Water tender: Any ground vehicle capable of transporting specified quantities of water.
Wet line: Temporary control line using water or other fire retardant liquid to prevent a low-intensity fire from spreading in surface fuels or to knock down a more intense fire.
Widowmaker: Any branch or treetop that is poorly or no longer attached to a tree, but still tangled overhead; does not discriminate among potential victims by gender or marital status.
Wildfire: An unplanned, unwanted wildland fire, including unauthorized human-caused fires, escaped wildland fire use events, escaped prescribed fire projects, lightning strikes, downed power lines, and all other wildland fires where the objective is to put the fire out.
Wildland: An area in which development is essentially nonexistent, except for roads, railroads, power lines, and similar transportation facilities. Structures, if any, are widely scattered.
Wildland fire engine: Fire apparatus specialized for accessing wildland fires with water, equipment and small crew. Size and agility of these units may also be useful for other urban missions.
Wildland Fire Use fires (WFU fires): naturally-ignited wildland controlled burns that are managed for purposes of achieving specific previously-defined resource management objectives.
Windfall: Tree knocked over or broken off by wind, increasing fuel loading and hampers building fireline. Also sometimes called blowdown. Large, unmanaged ares of dense blowdown can create serious fire hazards once the larger fuels become dry.