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NWCG Glossary of Wildland Fire (PMS 205)

Term Steward Status Definition
Situation Unit QMC Qualifications Management Committee, NISC NIMS Integration Subcommittee Approved Situation Unit staff collect, process, and organize situation information, prepare situation summaries, produce maps, and develop projections and forecasts related to the incident. They gather and disseminate information for incident and agency decision processe.
Situational Awareness (SA) QMC Qualifications Management Committee, LTSC Leadership Training Subcommittee, LDSC Leadership Development Subcommitte Approved An on-going process of gathering information by observation and by communication with others. This information is integrated to create an individual's perception of a given situation.
Six Minutes for Safety (6MFS) SRC Safety/Risk Management Committee Approved A daily safety briefing for wildland fire that focuses on high risk events found within a firefighter's scope of work that are performed on an infrequent basis.
size class IOSC Incident Operations Subcommittee Approved Identifies the fire size based on number of acres within the final fire perimeter
size class of fire IOSC Incident Operations Subcommittee Approved As to size of wildfire: Class A - one-fourth acre or less; Class B - more than one-fourth acre, but less than 10 acres; Class C - 10 acres or more, but less than 100 acres; Class D - 100 acres or more, but less than 300 acres; Class E - 300 acres or more, but less than 1,000 acres; Class F - 1,000 acres or more, but less than 5,000 acres; Class G - 5,000 acres or more.
sizeup IOSC Incident Operations Subcommittee Approved The evaluation of the fire to determine a course of action for suppression.
skid hose load ETSC Equipment/Technology Subcommittee Approved Load of hose specially arranged on top of a standard hose load to permit dropping the working line at the fire.
skid trail IOSC Incident Operations Subcommittee Approved Any road or trail formed by the process of skidding logs from stump to landing.
skidder unit ETSC Equipment/Technology Subcommittee Approved A self-contained unit consisting of a water tank, fire pump, and hose specially designed to be carried on a logging skidder for use in forest fire suppression.
skimmer AMC Aviation Management Committee Approved Any aircraft equipped to pick up water while moving on or over water.
sky cover IWSC Incident Weather Subcommittee Approved Amount of clouds and/or other obscuring phenomena that are detectable from the point of observation.
slash FMSC Fuels Management Subcommittee Approved Debris resulting from such natural events as wind, fire, or snow breakage; or such human activities as road construction, logging, pruning, thinning, or brush cutting. It includes logs, chunks, bark, branches, stumps, and broken understory trees or brush.
slash disposal FMSC Fuels Management Subcommittee Approved Treatment of slash to reduce fire hazard or for other purposes. Preferred to 'brush disposal.'
sling AMC Aviation Management Committee Approved A net attached by a lanyard to a helicopter cargo hook and used to haul supplies.
sling load AMC Aviation Management Committee, ETSC Equipment/Technology Subcommittee Approved Any cargo carried beneath a helicopter and attached by a lead line and swivel.
sling psychrometer AMC Aviation Management Committee, ETSC Equipment/Technology Subcommittee Approved A hand operated instrument for obtaining wet and dry bulb temperature readings and, subsequently, relative humidity.
slip-on tanker ETSC Equipment/Technology Subcommittee Approved A tank, a live hose reel or tray, an auxiliary pump, and an engine combined into a single one-piece assembly which can be slipped onto a truck bed or trailer.
slip-on unit MFES Mobile Fire Equipment Subcommittee Approved A self-contained unit including an auxiliary engine driven pump, piping, a tank, and hose storage that is designed to be placed on a truck chassis, utility bed, flat bed, or trailer. Such units can typically be attached and removed from the vehicle with a minimum amount of time and effort.
slope Approved The rise or fall in terrain measured in feet per 100 feet of horizontal distance measurement, expressed as a percentage.
slope class FDSC Fire Danger Subcommittee Approved One of five categories used to describe the topography of a fire danger rating area.
slope percent FDSC Fire Danger Subcommittee Approved The ratio between the amount of vertical rise of a slope and horizontal distance as expressed in a percent. One hundred feet of rise to 100 feet of horizontal distance equals 100 percent.
slope percentage (Point of Origin) (POO) GISC Geospatial Information Subcommittee Approved The ratio between the amount of vertical rise and horizontal distance of the terrain as expressed in a percent that represents the typical slope in the immediate vicinity of the point of origin of a fire. Point of origin is the location where a competent ignition source came into contact with the material first ignited and sustained combustion occurred.
slope winds IWSC Incident Weather Subcommittee Approved Small scale convective winds that occur due to local heating and cooling of a natural incline of the ground.
slopover IOSC Incident Operations Subcommittee Approved A fire edge that crosses a control line or natural barrier intended to confine the fire.
slug flow ETSC Equipment/Technology Subcommittee Approved The discharge of distinct pockets of water and air due to the insufficient mixing of foam concentrate, water, and air in a compressed air foam system.
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