Technical glossary

Salvo – To drop all of an airtanker's load of suppressant or retardant at once.

Sector – A designated segment of the fire perimeter handled as a unit for suppression purposes. Note Sector Boss under Fire Overhead.

Short-term Retardant – A water-based substance wherein water is the fire suppressing agent.

Siamese –

• without valves - a three-way hose line accessory to combine the flow from two lines of hose into a single discharge line, with no provisions to regulate stream flow. Note Wye without valves.
• with valves - A three-way hose line accessory to combine the flow from two lines of hose into a single discharge line. Valves located in the intake ports permit control of stream flow or shutting off one or both supply lines. Note Wye with valves.
• Note: If fitted with instantaneous twist-lock (unisex) couplings, a single accessory will perform the functions of both siamese and a wye.

Situation Report (SITREP) – An itemized list and/or written account, usually issued on a daily basis, detailing the status of various fire-related activities. A SITREP generally contains information on fire occurrence and area burned to date, fire suppression resources committed to going fires and resources on standby, number of fires in the various stages of control, fire danger class, fire weather forecast, and forest closures (if any).

Slash – Debris left as a result of forest and other vegetation being altered by forestry practices and other land use activities (e.g. timber harvesting, thinning and pruning, road construction, seismic line clearing). Slash includes material such as logs, splinters or chips, tree branches and tops, uprooted stumps, and broken or uprooted trees and shrubs.

Sling – A looped line of strap or rope attachable to a lanyard to lift, lower, or carry cargo beneath a helicopter. Note Cargo Net.

Slip-on Tank – A self-contained unit consisting of a water tank, fire pump, and hose designed for quick loading on conventional trucks.

Smoke –

• (1) The visible products of combustion rising above a fire.
• (2) A term often used when reporting a fire or probable fire in its initial stages. In fire management the following types of smoke are recognized:
  • Drift Smoke – Smoke that has drifted from its origin and has lost any original billow form.
  • Intermittent Smoke – Smoke that becomes visible occasionally.
  • Smoke Column – Smoke and other gases that form a column-shaped mass above a fire, characterized by sharply defined, billowed edges. Note Convection Column.

Smoke Column – Note Smoke (2).

Smokejumpers – Fire fighters trained and equipped to parachute to fires (usually in remote areas) for initial attack.

Smoke Management – Scheduling and conducting a prescribed burning program under predetermined burning prescriptions and firing techniques that will minimize the adverse impacts of the resulting smoke production in smoke sensitive areas.

Smoke Sensitive Area – An area in which smoke from outside sources is intolerable, owing to heavy population, transportation services, existing air pollution, and/or intensive recreation/tourist use.

Snag – A standing dead tree or part of a dead tree from which at least the smaller branches have fallen. Synonym - Chicot.

Spot Fire –

• (1) A fire ignited by firebrands that are carried outside the main fire perimeter by air currents, gravity, and/or fire whirls. Synonym - Jump Fire. Note Fire Behaviour.
• (2) A very small fire that requires little time or effort to extinguish.

Spotting – Note Spot Fire and Fire Behaviour.

Sprinkler Kit – A collection of water thieves, supply hose and water sprinkler heads used to wet the fuels along the fire perimeter or along a fireguard or in value protection.

Stages of Control – Note Control a Fire.

Standby – A state of readiness to take immediate action on detection of a fire. Note Period of Alert.

Strategy, Fire Suppression –

• (1) Preparedness - In a broad organizational sense the determination of when, where, and what level of resource deployment is required to meet anticipated fire incidence.
• (2) Active Fires - Determination of potential control problems based on a calculation of fire probabilities and development of an appropriate action plan that will best utilize the assigned resources in the control effort. Generally a command and planning decision as opposed to a line function.

  Note: Tactics, Fire Suppression.

String drop – A technique whereby a specified number of doors are opened in succession to give an extended pattern or string on the ground.

Subsidence – A meteorological term referring to the descending motion of air in the atmosphere, usually extending over a rather broad area, accompanied by warming and drying.

Suppression Crew – A unit of fire fighters assembled and organized for conducting fire suppression, either for initial attack and/or continuing work on fires. Crew size, specialization, and configuration determined by agency procedure. Synonyms - Fire Crew and Fire Squad.

Surfactant – A surface active agent or wetting agent. A formulation which when added to water in proper amounts will materially reduce the surface tension of the water and increase penetration and spreading abilities of the water.

Sustained Action Crew – Personnel trained, equipped and deployed to conduct suppression action on a wildfire for an extended period of time.