Glossary of Terms

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Water Tender:
A ground vehicle capable of transporting water in the field, generally used to supply engines.

Weather Information and Management System (WIMS):
An interactive computer system designed to accommodate the weather information needs of all federal and state natural resource management agencies. Provides timely access to weather forecasts, current and historical weather data, the National Fire Danger Rating System (NFDRS), and the National Interagency Fire Management Integrated Database (NIFMID).

Wet Line:
A line of water, or water and retardant, sprayed along the ground, which serves as a temporary control line from which to ignite or stop a low-intensity fire.

Wildland Fire:
Any non-structure fire, other than prescribed fire, that occurs in a wildland area.

Wildland Fire Implementation Plan (WFIP):
A progressively developed assessment and operational management plan that documents the analysis and selection of strategies and describes the appropriate management response for a wildland fire that is managed for resource benefits.

Wildland Fire Situation Analysis (WFSA):
A decision-making process that evaluates alternative suppression strategies against selected environmental, social, political, and economic criteria. Provides a record of decisions. A WFSA is required when the documentation of suppression decisions needs to occur when (1) a wildland fire escapes initial actions or is expected to, or (2) a wildland fire managed for resource benefits exceeds prescription parameters in the fire management plan, or (3) a prescribed fire exceeds its prescription and is then declared a wildland fire.

Wildland Fire Use:
The management of naturally ignited (usually by lightning) wildland fires to accomplish specific pre-stated resource management objectives in predefined areas outlined in Fire Management Plans.

Wildland Fuel:
Combustible material that can be consumed by fire which includes naturally occurring live and dead vegetation, such as grass, leaves, ground litter, plants, shrubs and trees, and excessive buildups of these materials resulting from resource management and other land use activities, as well as from natural plant growth and succession.

Wildland/Urban Interface:
The line, area, or zone where structures and other human development meet or intermingle with undeveloped wildland or vegetative fuels. Often incorrectly referred to as the "interzone" or "urban/wildland interface."

Windthrow:
A natural phenomenon of gale or hurricane force winds that every year blow over hundreds of acres of trees in uncut stands and along cut block boundaries and road allowances. Windthrown timber that is not salvaged can also create a fire hazard and can produce habitat conditions that increase the risk of insect epidemics.

Wind Vectors:
Wind directions used to calculate fire behavior.