This glossary includes some of the more commonly used terminology as they relate to
wildland fire behavior and fire weather forecasting. The second section of this glossary
includes the abbreviations and descriptors for the values utilized in determining current
and predicted fire danger.
Adjective Rating (R) - A public information component
of the NFDRS specific to the rating of fire danger. Adjective ratings are: low(L),
moderate(M), high(H), very high(VH) and extreme(E).
Aerial Fuels - All live and dead vegetation located in the
forest canopy or above the surface fuels, including tree branches and crowns,
snags, moss and high brush.
Appropriate Management Response (AMR) - Specific actions taken in
response to a wildland fire to implement protection and fire use objectives. Formerly
known as the appropriate suppression response which consisted of the confine, contain, and
control tactical strategies. (NWCG terminology adopted 06/12/97)
Aspect - The direction a slope faces the sun. Expressed in cardinal
direction. Same as exposure.
Available Fuel - The portion of the total fuel that actually burns.
Backfire - A fire set along the fire side of a control line or barrier
to consume the fuel in the path of an advancing wildfire or to change the direction of
force of the fire's convection column. Note: Doing this on a small scale and with closer
control, in order to consume patches of unburned fuel and aid in control line construction
is distinguished as burning out.
Backing Fire - A slowly advancing fire which is burning into or
against the wind or downslope. See head fire.
Blowup - Sudden increase in fire intensity or rate of spread
sufficient to preclude direct suppression or to upset existing suppression strategies.
Often accompanied by violent convection and may have other characteristics of a fire
storm.
Breakout - See slopover.
Buildup - 1) Cumulative effects of drying (during a preceding period)
on the current fire danger. 2) Acceleration of a fire with time. 3) Increase in strength
of a fire suppression organization.
Burning Index (BI) - A measure of fire intensity. BI combines the
Spread Component and Energy Release Component to relate to the contribution of fire
behavior to the effort of containing a fire. BI has no units, but in general it is 10
times the flame length of a fire.
Burn Out - See backfire and backing fire.
Burning Period - That part of each 24-hour period when fires
will spread most rapidly. Most commonly 10:00 am to 4:00 pm.
Canopy - The stratum containing the crowns of the tallest vegetation
present, (living or dead) usually above 20 feet.
Chain - A non-metric measure of distance common to land surveying,
forestry and fire management. One chain equals 66 feet.
Class of Fire (as to kind of fire) - Class A fires are those that are
burning solid fuels such as wood and vegetation. Class B fires are those that include
flammable liquids. Class C fires involve electrical equipment and Class D fires involve
burning metals.
Class of Fire (as to size of wildland fires) - Class A = 0.25 acres or
less, Class B = 0.25-<10 acres, Class C = 10-<100 acres, Class D = 100-<300 acres
and Class E = 300+ acres.
Confine a Fire - To restrict the fire within determined boundaries
established either prior to the fire or during the fire. (Obsolete terminology)
Contain a Fire - To take suppression action, as needed, which can be
reasonably be expected to check the fire's spread under prevailing conditions. (Obsolete
terminology)
Control a Fire - To complete a control line around a fire, any spot
fires therefrom, and any interior islands of unburned fuel to be saved; burn out any
unburned area adjacent to the fire side of the control lines; and cool down any hotspots
that are immediate threats to the control line, until the lines can reasonably be expected
to hold under foreseeable conditions. See suppress a fire. (Obsolete terminology)
Controlled Burning - See prescribed burning.
Control Line (Fire Line) - An inclusive term for all constructed or
natural fire barriers and treated fire edge used to control a fire.
Convection Column - The thermally produced, ascending column of gases,
smoke, and debris produced by a fire.
Creeping Fire - Fire burning with a low flame and spreading slowly.
Crown Fire - A fire that advances from the top to top of trees or
shrubs more or less independently of the surface fire. Sometimes crown fires are classed
as either dependent or independent, to distinguish the degree of independence from the
surface fire's influence. See crown out.
Crown Out - With reference to wildland fire, to rise from ground level
and begin advancing through the vegetation crowns. To intermittently ignite the crowns as
the surface fire advances.
Danger Index - A relative number indicating the severity of wildfire
danger as determined from burning conditions and other variable factors of fire danger.
Drift Smoke - Smoke that has drifted from its point of origin and has
lost any original billow form.
Drought Index - A number representing net effect of evaporation,
transpiration and precipitation in producing cumulative moisture depletion in deep duff or
upper soil layers. See Keetch-Byram & Palmer Drought Indices.
Dry Lightning Storm - A lightning storm with negligible precipitation
reaching the ground.
Duff - The partially decomposed organic material of the forest floor
beneath the litter or freshly fallen twigs, needles and leaves. See litter.
Effective Wind Speed - The mid-flame wind speed adjusted for the
upslope effect on fire spread.
Equilibrium Moisture Content (EMC) - The level at which dead fuels
neither gain nor lose moisture with time, under specific constant temperature and
humidity. The vapor pressure in the air is equal to the vapor pressure in the fuel. A fuel
particle, at EMC, will have no net exchange of moisture with its' environment.
Energy Release Component (ERC) - Based upon the estimated potential
available energy released per unit area in the flaming zone of a fire. It is dependent
upon the same fuel characteristics as the spread component (SC). The day to day variations
of the ERC are caused by changes in the moisture contents of the various fuel classes,
including the 1000 hour time lag class. ERC is derived from predictions of the rate of
heat release per unit area during flaming combustion and the duration of the burning.
Expressed in BTU's per square foot.
Escaped Fire - A fire which has exceeded initial attack capabilities.
Extreme Fire Behavior - Implies a level of wildfire behavior
characteristics that ordinarily precludes methods of direct attack. One or more of the
following is usually involved: High rates of spread; prolific spotting and or crowning;
presence of fire whirls; a strong convection column. Predictability is difficult because
such fires often exercise some degree of influence on their environment, behaving
erratically and sometimes dangerously.
Fine Fuels - Fuels such as grass, needles, fern, tree moss, some slash
types & leaves which ignite readily and are consumed rapidly when dry. Also called
flash fuels.
Fine Fuel Moisture - The probable moisture content of fast-drying
fuels which have a time lag constant of one hour or less; such as, grass, leaves, ferns,
tree moss, draped needles, and small twigs.
Fingers of the Fire - The long narrow tongues of a fire projecting
from the main perimeter.
Fire Behavior - The manner in which a fire reacts to the variables of
fuel, weather and topography.
Fire Behavior Forecast - Fire behavior predictions prepared for each
operational period by a Fire Behavior Analyst (FBAN) to meet planning needs of fire
management personnel. The forecast interprets fire calculations made, describes expected
fire behavior by areas of the incident, with special emphasis on personnel safety, and
identifies hazards due to the fire for ground and aerial activities.
Fire Behavior Prediction System (FBPS) - A fire behavior prediction
system developed to make site specific fire behavior predictions utilizing fuels, weather
and topographic inputs. The FBPS operates on site and time specific data to evaluate fire
behavior as it changes with time and from point to point.
Firebrand - Any source of heat, natural or manmade, capable of
igniting wildland fuels. Flaming or glowing fuel particles that can be carried naturally
by wind, convection currents, or by gravity into unburned fuels.
Firebreak - A natural or constructed barrier utilized to stop or check
fire spread that may occur or to provide a control line (fire line) from which to work.
Sometimes referred to as a fire lane.
Fire Danger - Resultant of both constant and variable fire danger
factors, which affect the ignition, spread and difficulty of control of fires and the
damage they cause.
Fire Danger Rating - A fire management system that integrates the
effects of selected fire danger factors into one or more qualitative or numerical indices
of current protection needs. See fire danger.
Fire Edge - The boundary or perimeter of a fire at a given moment.
Fire Effects - The physical, biological and ecological impact of fire
on the environment.
Fire Environment - The surrounding conditions, influences, and
modifying forces that determine the behavior of fires.
Fire Intensity - The rate of heat release for an entire fire at a
specific point in time. See fireline intensity.
Fireline - The part of a control line that is scraped or dug to
mineral soil. Sometimes referred to as a fire trail. See control line.
Fireline Intensity - The rate of heat energy released during
combustion per unit length of fire front. It is usually expressed in BTUs/second/foot.
Fire Load Index (FLI) - A rating of the maximum effort required to
contain all probable fires occurring within a rating area during the rating period. It is
the cumulative index of the NFDRS. It is designed to combine the projections of fire
occurrence and behavior into a single number that can be related to the total fire
suppression job. The meaning of FLI has been left to the user. By itself, it does not tell
the user much about the nature of the fire management problem. One needs to examine the
individual components and indices that are the basis for the FLI. It ranges over a scale
of 1-100 and has no units.
Fire Management Plan - A strategic plan that defines a program to
manage wildland and prescribed fires and documents the Fire Management Program in the
approved land use plan. The plan is supplemented by operational procedures such as
preparedness plans, preplanned dispatch plans, prescribed fire plans and prevention plans.
(NWCG terminology adopted 06/12/97)
Fire Retardant - Any substance except plain water that by chemical or
physical action reduces the flammability of fuels or slows their rate of combustion.
Fire Season - The period or periods of the year during which wildland
fires are likely to occur, spread and do sufficient damage to warrant organized fire
suppression activities.
Fire Storm - Violent convection caused by a large continuous area of
intense heat energy. Often characterized by destructively violent surface indrafts near
and beyond the fire perimeter, and sometimes by tornado-like whirls.
Fire Weather Forecast - A weather prediction specially prepared for
use in fire management activities.
Fire Weather Station - A meteorological sampling station specifically
equipped to measure weather and fuel elements which have an important effect on fire
management activities.
Firewhirl - A spinning, moving column of ascending air rising from a
vortex and carrying aloft smoke, debris and flames. These range in size from a foot or two
in diameter to small tornadoes in size and intensity.
Flame Height - The average height of flames as measured on a vertical
axis. It may be less than flame length if the flames are angled.
Flame Length - The distance measured from the tip of the flame to the
middle of the flaming zone at the base of the fire. It is measured on a slant when the
flames are tilted due to the effects of wind and/or slope.
Flaming Front - The zone of a moving fire within which the combustion
is primarily flaming. Behind this flaming zone, combustion is primarily glowing. Light
fuels typically have a shallow, flaming front, whereas heavy fuels have a deeper front.
Flammability - The relative ease with which fuels ignite and burn
regardless of the quantity of the fuels.
Flanks of the Fire - The parts of a fire's perimeter that are roughly
parallel to the main direction of spread.
Flareup - Any sudden acceleration of fire spread or intensification of
the fire. Unlike blowup, a flareup is relatively short duration and does not radically
change strategic or tactical management actions.
Flash Fuels - See fine fuels.
Flashover - Rapid combustion and/or explosion of unburned gasses
trapped at some distance from the fire front. Usually occurs only in poorly ventilated
topography. More commonly associated with structural fire behavior.
Free Burning - The condition of a fire or portion of a fire that has
not been checked by barriers or suppression activities.
Fuelbreak - A wide strip or block of land on which the native
vegetation has been permanently modified so that fires burning into it may be more readily
suppressed. May or may not have firelines constructed in it prior to a fire occurrence.
Fuelbreak System - A series of fuelbreaks creating a strategically
located system.
Fuel Loading - The weight of fuels in a given area, usually expressed
in tons per acre. Fuel loading may be referenced to fuel size or timelag categories; and
may include surface fuels or total fuels.
Fuel Model - See fuel type.
Fuel Moisture Content (FMC) - The quantity of moisture in fuel
expressed as a percentage of the weight when thoroughly dried at 212F.
Fuel Moisture Sticks - A specifically prepared set of sticks of known
dry weight continuously exposed to the weather and periodically weighed to determine the
changes in moisture content as an indication of moisture changes in wildland fuels.
Typically representative of the 10 hour timelag fuel size.
Fuel Type - An identifiable association of fuel elements of
distinctive species, form, size, arrangement or other characteristics that will cause a
predictable rate of fire spread and intensity under specific weather and topographic
conditions. Also referred to as fuel model.
Ground Fire - Fire that consumes the organic material beneath the
surface litter.
Ground Fuels - All combustible fuels lying beneath the ground surface
including deep duff, roots, rotten buried logs, peat and other woody debris.
Haines Index - A national fire-weather index based on the stability
and moisture content of the lower atmosphere and their direct relationship to the growth
of large fires. The index is from 1-6 with 1 being the lowest potential for large fire
growth while 6 is the highest large fire growth potential.
Hazard - A fuel complex defined by kind, arrangement, volume,
condition, and location that forms a special threat of ignition or suppression difficulty.
Hazard Reduction - Any treatment of a hazard that reduces the threat
of ignition and spread of fire.
Head Fire - A fire spreading or set to spread with the wind or up
slope.
Head of Fire - The most rapidly spreading portion of a fire's
perimeter, usually to the leeward or up slope.
Heat Per Unit Area - The heat released by a square foot of fuel while
the flaming zone of the fire is in that area. Expressed as BTUs/sq.ft.
Heat Transfer - The transfer or exchange of heat energy by radiation,
conduction or convection.
Heavy Fuels - Fuels of large diameter such as snags, logs and large
limb wood which ignite and are consumed more slowly than fine or flash fuels. Also called
coarse fuels. See fine & flash fuels.
Horizontal Continuity - The extent or horizontal distribution of fuels
at various levels or planes.
Hotspot - A particularly active part of a fire.
Human Caused Risk (HCR) - The number relating to the expected number
of person caused fires that a rating area will be exposed to during the rating period. It
is based on the historical fire occurrences in relation to weekday vs. weekend person
caused fires.
Ignition - The initiation of combustion.
Ignition Component (IC) - Related to the probability of a firebrand
producing a fire that will require suppression action. It is mainly a function of the 1
hour time lag (fine fuels) fuel moisture content and the temperature of the receptive fine
fuels. IC has no units. A percentage of probability from 1-100.
Ignition Temperature - The lowest temperature of a substance at which
sustained combustion can be initiated. Also called kindling point.
Initial Attack - An aggressive suppression action consistent with
firefighter and public safety and values to be protected.
Islands - Patches of unburned fuel inside the fire's perimeter.
Keetch-Byram Drought Index (KBDI) - A number between 0-800
representing the amount of moisture in the top 8 inches of soil. Zero is saturated, 800 is
maximum drought stress. It is calculated from recent precipitation measurements in
relation to the average annual precipitation. It is important to note that the KBDI is
customized for each geographic area and that often the scale shows less of a range in
variation.
Ladder Fuels - Fuels which provide vertical continuity between strata.
Fire is able to carry from surface fuels by convection into the crowns with relative ease.
Lightning Activity Level (LAL) - A numerical rating from the lowest of
1 to the highest of 6, keyed to the start of thunderstorms and the frequency and character
of cloud-to-ground lighting forecasted or observed on a rating area during a rating
period.
Lightning Fire - A fire caused directly or indirectly by lightning.
Lightning Risk (LR) - Number relating to the expected number of cloud
to ground lightning strikes capable of igniting fires that a rating area will be exposed
to during the rating period.
Litter - The uppermost layer of loose debris composed of freshly
fallen or slightly decomposed organic materials such as dead sticks, branches, twigs, and
leaves or needles.
Long-range Spotting - Firebrands which are carried high into the
convection column and then fall out downwind beyond the main fire, starting new fires.
Such spotting can easily occur 1/4 mile or more from the firebrands' source.
Management Ignited Fire - See prescribed burning. (Obsolete
terminology)
Maximum Manageable Area (MMA) - The area of a prescribed fire where
the fire is managed as part of the burn plan prescription parameters and constraints. A
prescribed fire is managed within the MMA and all prudent and practical actions are taken
by the prescribed fire team to maintain the fire within this predetermined area. If the
prescribed fire breaches this perimeter line, the fire is declared a wildfire and the
appropriate management response is initiated. This action usually consists of rapid and
aggressive suppression tactics. (NWCG terminology adopted 06/12/97) Replaces the obsolete
terminology of Maximum Allowable Perimeter (MAP).
Midflame Winds - The wind speed that affects a surface fire and is
used in the mathematical fire behavior prediction models. It is usually less than the
standard 20 foot wind speed.
Moisture of Extinction - The fuel moisture content at which the fire
will not spread or spreads only sporadically and in an unpredictable manner.
NFDRS (National Fire Danger Rating System) - A multiple index system
developed to provide information about current and predicted fire danger conditions.
Normal Fire Season - 1) A season when weather, fire danger, and number
and distribution of fires are about average. 2) Period of the year that normally comprises
the fire season.
Origin - Location where the fire started.
Palmer Drought Index - A drought index commonly used in agriculture
which defines seven different levels of drought classification. Less commonly used in fire
management because it cannot be readily customized to specific locales.
Perimeter - The total length of the outside edge of the burning or
burned area.
Plume Dominated Fire - A fire where the energy produced by the fire in
conjunction with forces such as atmospheric instability has created convective forces
which dominate the surrounding environment. Such fires are extremely unpredictable, spread
in various directions simultaneously, and exhibit extreme fire behavior. These fires are
extremely dangerous and are often large in size . The formation of plume dominated fires
is often directly related to high Haines indices.
Pockets - Deep indentations of unburned fuel along the fire's
perimeter. Normally, fireline will be constructed across pockets and they are then burned
out.
Preparedness - Activities that lead to a safe, efficient and cost
effective fire management program in support of land and resource management objectives
through appropriate planning and coordination. (NWCG terminology adopted 06/12/97)
Prescription - Measurable criteria which guide selection of
appropriate management response and actions. Prescription criteria may include safety,
economic, public health, environmental, geographic, administrative, social or legal
considerations. (NWCG terminology adopted 06/12/97)
Prescribed Burning or Prescribed Fire - Controlled application of fire to wildland fuels in either their natural or modified state, under specified environmental conditions which allow the fire to be confined to a predetermined area and at the same time to produce the intensity of heat and spread required to attain planned and approved resource management objectives.
Also called controlled burning or formerly referred to as management ignited prescribed
fire. A written, approved prescribed fire plan must exist and, requirements of the
National Environmental Policy Act must be met, prior to ignition. (NWCG terminology
adopted 06/12/97)
Prescribed Natural Fire (PNF) - A naturally occurring fire which is
managed under prescribed conditions and allowed to "run its' course" without
endangering public safety or significant resource losses. (Obsolete terminology)
Probability of Ignition (PI) - The rating of the probability that a
firebrand (glowing or flaming) will cause a fire, providing it lands on receptive fuels.
It is calculated from air temperature, fuel shading, and fuel moisture. Portrayed on a
1-100% scale. See Ignition Component.
Rate of Spread (ROS) - The relative activity of a fire in extending
its horizontal dimensions over time. Expressed as a rate of increase of the total
perimeter of the fire, as a rate of forward spread of the fire front, or as a rate of
increase in area, depending upon the intended use of the information. Usually it
represents the forward spread and is expressed in chains per hour or meters per hour for a
specific period in the fire's history.
Rear of the Fire - Portion of the edge of the fire that spreads the
slowest.
Reburn - 1. Subsequent burning of an area in which fire has previously
burned but has left flammable fuel that ignites when burning conditions are more
favorable. 2. An area that has reburned.
Red Flag Warning - A term used by fire-weather forecasters to call
attention to weather of particular importance to fire behavior. The purpose is to call
attention of forecast users to special conditions of limited duration that may result in
extreme burning conditions. May also bring attention to rapid changes in weather
conditions which may increase the fire danger more rapidly than standard fire danger
rating indices.
Relative Humidity (RH) - The ratio of the amount of moisture in a
given volume of atmosphere to the amount that volume would contain if it were saturated.
The ratio of the actual vapor pressure to the saturated vapor pressure.
Remote Automated Weather Station (RAWS) - A special remote fire
weather observation station which takes timed measurements of the various weather factors
used to calculate fire danger and behavior. These stations usually transmit data via
satellite telemetry to the National Interagency Fire Center for distribution to fire
managers nation-wide.
Resistance to Control - The relative difficulty of constructing and
holding a fireline as affected by resistance to line construction and by fire behavior.
Also called difficulty of control.
Risk - 1) The chance of fire starting as determined by the presence
and activity of causative agents. 2) A causative agent. 3) A number related to the
potential number of firebrands to which a given area will be exposed during the rating
day.
Running Fire - Behavior of a fire spreading rapidly with a
well-defined head.
Scorch Height - Average heights of foliage browning caused by a fire.
Also referred to as scorch line.
Short-range Spotting - Firebrands, flaming sparks, or embers are
carried by surface winds, starting new fires beyond the zone of direct ignition by the
main fire. The range of such spotting is usually less than 1/4 mile. See Long-range
Spotting.
Slash - Debris left after logging, pruning, thinning or brush cutting.
Includes logs, chunks, bark, branches, stumps, and broken understory trees or brush.
Slopover - A fire edge that crosses over a barrier or control line
intended to confine or stop a fire's spread. Also called a breakout.
Smoke Management Forecast - A forecast issued daily during specific
periods advising fire managers of atmospheric conditions with special emphasis on elements
which will affect the dispersal of pollutants from a fire.
Smoldering fire - Behavior of a fire burning without flame and
spreading very slowly.
Snag - A dead standing tree.
Spot Fire - Fire ignited outside the perimeter of the main fire by
flying sparks or embers.
Spotting - Behavior of a fire producing sparks or embers that are
carried by the wind or convection column and ignite new fires beyond the zone of direct
ignition by the main fire.
Spot Weather Forecast - A special weather forecast issued to fit the
time, topography and weather of a specific fire. Requires specific on-site weather
observations and measurements.
Spread Component (SC) - A rating of the forward rate of spread of a
head fire.
Staffing Level (SL) - A public information component of the NFDRS
relating to the level of fire management staffing. Staffing levels are from 1-5 with 1
being the lowest and 5 the highest.
State of the Weather (W) - A brief description of current weather that
expresses the amount of cloud cover, kind of precipitation, and/or restrictions to
visibility being observed at a weather observation site.
Surface Fire - Fire that burns surface litter, other loose debris and
small vegetation.
Surface Fuels - All materials lying on, or immediately above, the
ground, including needles or leaves, duff, grass, small dead wood, downed logs, stumps,
large limbs, low brush and reproduction.
Surface Wind - The wind measured 20 feet above the average top of the
vegetation. Often a combination of local and general winds. Referred to as "20 Foot
winds".
Thermal Belt - An area of a mountainous slope that typically
experiences the least variation in diurnal temperatures, has the highest average
temperature, and thus, the lowest average relative humidity.
Timelag - An indication of the rate a dead fuel gains or loses
moisture due to changes in its environment. The time necessary for a fuel particle to gain
or lose approximately 63% of the difference between its initial moisture content and its
equilibrium moisture content. Fuels are usually grouped into 1-hr; 10-hr; 100-hr; and
1000hr timelag categories.
Torching - Fire burning principally as a surface fire that
intermittently ignites the crowns of trees or shrubs as it advances.
Wildfire - Any unwanted wildland fire. (NWCG terminology adopted
06/12/97)
Wildland - An area in which human development is essentially
non-existent except for roads, railways, powerlines and similar transportation facilities.
Wildland Fire - Any non-structural Fire, other than prescribed fire,
that occurs in the wildland. (NWCG terminology adopted 06/12/97)
Wildland Fire Situation Analysis - A decision-making process that
evaluates alternative management strategies against selected safety, environmental,
social, economical, political and resource management objectives as selection criteria.
Formerly called the escaped fire situation analysis (EFSA). (NWCG terminology adopted
06/12/97)
WIMS (Weather Information Management System) - A computerized system
for the collection and evaluation of weather data from fire weather stations for use in
the calculation of NFDRS indices.
Wind Driven Fire - A fire in which the local and/or topographic winds
have the overriding control on the rate of spread and growth of a fire. The power of the
wind is greater than the power of the fire.
Zone Weather Forecast - A portion of the general weather forecast
issued on a regular basis during the normal fire season specifically to fit the
requirements of fire management needs. These zones and or areas are a combination of
administrative and climatological areas.
Interpreting Fire Weather Station Observations & Forecasts
Interpreting Display Observations W = State of The
Weather
0 = Clear
1 = Scattered Clouds (1/10 - 5/10)
2 = Broken Clouds (6/10 - 9/10)
3 = Overcast )More than 9/10)
4 = Foggy
5 = Drizzling
6 = Raining
7 = Snowing or Sleeting
8 = Showering
9 = Thunderstorm
DRY TMP = Dry Bulb Temperature (F)
RH = Relative Humidity (%)
ML = Morning Lightning Activity Level (From midnight to observation time)(1-6 Scale)
HC = Human Caused Risk (1-6 Scale)
WIND DIRECTION = Cardinal Direction
WIND SPEED = Miles Per Hour (MPH)
10 HR = 10 Hour Time Lag Fuel Moisture (%)
MAX TEMP = Maximum Temperature (F)
MIN TEMP = Minimum Temperature (F)
MAX RH = Maximum Relative Humidity (%)
MIN RH = Minimum Relative Humidity (%)
DUR = Duration of Rain (Hours)
AMT = Amount of Rain (Inches)
YL = Yesterday's Lightning Activity Level (1-6 Scale)
FHC = Forecasted Human Caused Risk (1-6 Scale)
Interpreting Fire Danger Indices
7MSGC = 78 or 88 System, Fuel Model, Slope Class, Grass Type, Climate Class
WS = Predicted Wind Speed
WDY = Woody Fuel Moisture
HRB = Herbaceous Fuel Moisture
1H = I Hour Fuel Moisture
10 = 10 Hour Fuel Moisture
HU = 100 Hour Fuel Moisture
TH = 1000 Hour Fuel Moisture
IC = Ignition Component
SC = Spread Component
EC = Energy Release Component
BI = Burning Index
FL = Fire Load Index
SL = Staffing Level
R = Adjective Fire Danger Rating
KBDI = Keetch-Byram Drought Index